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DIFFERENTIALPRESSURE TYPEFLOWMETER

TableofContents

SICNewGeneration DF-type StandardDifferential Pressure Flowmeter
ChapterIModel SelectionofFlowThrottlingDevice· 2
Chapter I Qualification Certificate for Differential Pressure Flowmeter·
ChapterIII Differential Pressure Design Standard and Production Standard 12
Chapter IV Throttling Device 13
ChapterVStandard OrificeDifferentialPressureFlowmeter 16
Chapter VINozzle Differential Pressure Flowmeter 28
Chapter VII Standard Venturi Differential Pressure Flowmeter : 32
Chapter VII Non-standard Throttling Element· 36
SICNewGenerationDFYT-typeIntegrated OrificeFlowmeter 38
SIC New Generation DFPH-type Multi-hole Orifice (Balanced Orifice Flowmeter.. 47
SIC New Generation DFX-type Wedge Flowmeter 54
SIC New Generation DFJ-type Rectangular Flowmeter 66
SICNewGeneration DFV-typeV-cone Flowmeter 72
SIC New Generation DFB-type SDB Averaging Pilot-tube Flowmeter 77
DFFAir Volume MeasuringDevice 90
Annular Orifice Plate 94
Accessories of Throttling Device 98
ScheduleIDataCorrectionafterRealFlowCalibration 101
Schedule IPrecautions for Ordering .102

SICNewGenerationDF-type Standard DifferentialPressureFlowmeter

Standard differential pressure flowmeters are divided into three types:orifice, nozzle and venturi tube

ChapterI Model Selection ofFlow ThrottlingDevice

Throttling Device Types

Processconnection mode

Note: The flange types in this process connection diagram are for reference only, and shall be subject to the product contract.
S Others
\* Installation precautions:In order to ensure the concentricity for meter installation,the body must be assembled before connection with the user's pipe

Note:In case of external flange,refer to the remarks in the Quotation List for the flange material.

Recommendation:The valve diameterof high-temperature and high-pressure products shallbe at least DN10;
Note:For conventional valves,the size of DN6 interface is 143,and that of DN15 interface is 22 4.

ChapterII Qualification Certificate forDifferential Pressure Flowmeter

1.CNASLaboratory Accreditation Certificate

2.Certificate for Qualified SuppliersIssued by China National Nuclear Corporation (CNNC)

N

8

中核集团

合格供应商证书

证书编号：CNNC-210091402

重庆川仪自动化股份有限公司

受中核集团委托，依据其合格供应商评价的有关规定，经评审，贵单位具有向中核集团总部及下属单位提供产品（或服务）的资格。

此证书适用于以下产品（或服务）：

1E级仪控系统机柜的设计、制造和服务；1E级阀门驱动装置的设计、制造和服务；工业自动化仪表盘、柜、台、箱系列产品的设计、制造；低压成套开关设备、配电箱、低压无功功率补偿装置的设计、制造；电磁流量计、涡街流量计、差压流量计（文丘里管、楔形、孔板、V锥）的设计、制造和服务；电动执行机构（含智能型）、电液执行机构的设计开发、生产和服务；宝石轴承（球形刚玉轴承、大通孔宝石轴承、刚玉通孔嵌件轴承）的制造；（未完见续）

注册地址：重庆市北碚区人民村1号限认证中心有限公司原认证有限公司证书专用章（1）

颁证日期：2021年12月03日有效期至：2024年08月14日

注：在有效期内，供应商每年至少应接受一次监督评审，若监督评审结论合格，资格可顺延一年；若监督评审结论不合格，证书作废。合格供应商证书状态可在www.cnnc.com.cn实时查询。

3.ProductionLicense ofTS Special Equipment

4.EU CE Certificate of Compliance

Certificate of Compliance

No.3J200312.CCA0N98 Technical Construction File no. SHH/WL/TCF1.0/MD

Certificate's Holder:

Chongqing Chuanyi Automation Co., Ltd. Flowmeter Branch
No. 61 Huangshan Ave, Yubei Distiiet Chongqing. China

Manufacturer:

Chongqing Chuanyi Automation Co.,Ltd. Flowmeter Branch
No.61,MiddleSectionof HuangshanAvenue,New NorthZone,Chongqing,hina

Certification ECM Mark:

Product: Model(s): Verification to:

ThrottleDevice DFKBZ,DFBPH,DFKBF,DFZT

Standard: EN61000-3-2:2014,EN61000-3-3:2013 related toCEDirective(s): 2014/30/EU (ElectromagneticCompatibility)

Remark:Theproduct(s)hasbeen verified onavoluntarybasis.Theproduct(s)satisfies therequirementsof theCertificationMarkof ECM,inreferencetotheabovelisted Standard(s).TheaboveCompliance Mark Canbeafixedontheproduct(s)accordinglytotheECMregulationaboutitsreleaseanditsuse.The regulationcanbefoundatwww.entecerma.it.ThisCertificateofCompliancecanbecheckedforvalidity at www.entecerma.it

Thisverification doesn't imply assessment of the production of the product(s).

CE

Weattest that a TCF for theCE MarkingprocessisinplaceWhereas the Manufacturer isResponsibleto start theCEMarking Certification Procedure andto perform all the necessary activities, as required by the Directive before placing the EMark on the product(s).

Date of issue 12 March 2020

Deputy Manager Amanda Payne 52 如

Ente Certificazione Macchine Srl

Via Ca'Bella,243-Loc.Castello di Serravalle -40053Valsamoggia (BO)- ITALY +390516705141+390516705156 区info@entecerma.itwww.entecerma.it

5.Type Approval Certificate forMeasuring Devices

6.Production License for Measuring Devices

7.Metering Certificate for Real Flow Calibration Device

8.WeldingQualification Certificate

Civil nuclear welding qualification

Civil nuclear welding qualification

Civil nuclear welding qualification

FeIV-class welding qualification

FeIII-class welding qualification

FeII-class welding qualification

9.Compulsory Inspection Report

10.Sulfur and Hydrogen Resistance Report

11.WeldingProcedureQualificationCertificate

Chapter III Differential Pressure Design StandardandProductionStandard

1.The standard differential pressure flowmeteris designed and manufactured in strict accordance with the national standard GB/T2624-2006 or the international standard ISO5167,and checked according to the JJG 64O-2016Verification Regulation of Differential Pressure Type Flowmeter.

2.The Company has obtained the certificate for qualified suppliers issued by China National Nuclear Corporation，Production License of TS Special Equipment,EUCE Certificate of Compliance and the Production License for Measuring Devices.

3.Welding personnel of the manufacturer are qualified for pressure vessel and nuclear power grade welding，aswell asFeII-class,FeII-classand FeIVclass welding.

4.522.6 in national standard GB/T 2624.3-2006 indicates that:

The inner surface roughness of long-radius nozzle:Ra 10-4d;

5.2.6.1 indicates that:

The roughness of long-radius nozzle measuring pipe and upstream pipe:Ra 3.2 10-4D.

5.HG/T 20592\~20635-2009 Steel Pipe Flanges, Gaskets and Bolting,and GB/T 9124-2019 Steel Pipe Flanges specify that:

For pipe flanges with nominal pressure greater than or equal to PN1oO and greater than or equal to Class 6Oo,the forgings shall be Class I or above; for other pipe flanges,and forgings shall be Class I or above.

6.NB/T47008-2017 Carbon and Alloy Steel Forgings for Pressure Equipment specifies that:

Carbon steel and alloy steel forgings for pressure equipment shall meet the requirements of forgings in the standard.Welded shells shall use forgings of Class III.

7.The national standard - GB/T 5310-2017 Seamless Steel Tubes for High Pressure Boilers specifies that:

Carbon steel and alloy steel pipe materials shall meet requirements of the standard.

8．2.2(1) in the TSG 11-2020 Regulation on Safety Technology forBoilerindicatesthat:

The boiler pressure element and the bearing element welded with the pressure element shall be made of killed steel.

9.NB/T 47013-2015 Nondestructive Testing Requirements for Pressure Equipment specifies that:

For TSG products,the fillet weld shall be subject to a penetration inspection,and qualified at Grade I, and the butt weld shall be subject to a radiographic inspection,with an inspection proportion of 20 % ，and qualified at Grade II.

10.TS products are designed according to the TSG11-2O20 Regulation on Safety Technology for Boiler and GB/T 165O7 Water-tube Boilers,and manufactured according to the GB/T 2624.3-2006 and SJTH[2018]No.515.

11.The TSG 11-2020 Regulation on Safety Technology for Boiler specifies that:

TS products shall be subject to a penetration inspection,with a proportion of 100 % ,and be qualified at Grade I;

The NB/T47013-2015 Nondestructive Testing of Pressure Equipment specifies that:

TS products shall be subject to a non-destructive testing according to the requirements in the standard.

12.The manufacturer is provided with a thickness gauge to make sure that the measured pipe thickness meets the requirements of strength calculation and ensure the safety requirements of TS products.

13.Low-temperature alloy steel products shall be preheated before welding,and receive annealing heat treatment after welding，so as to reduce or eliminate the residual stress of welded joints,prevent cracks,and improve the structure and performance of metal in welds and heat affected zones.

14.The manufacturer is equipped with an alloy analyzer,which can be used for the qualitative analysis onalloy steel materialsin the factory,and to recheck the measuring tube,pressure tapping pipe and all welding spots.

15.The Company is equipped with a complete real flow calibration system,which can be used for Water and gas calibration in the factory to ensure product accuracy.

ChapterIV Throttling Device

1.MeasurementPrincipleof ThrottlingDevice

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When the fluid filled in the pipeline flows through the throttling devices (orifice,nozzle,etc.）in the pipeline,it willlocally contract at the throttling part of the throttling device,thus increasing the flow rate and reducing the static pressure.Therefore,a pressure drop or differential pressure is generated ahead of and behind the throttling devices.The greater the flow rate of the medium,the greater the differential pressure generated ahead of and behind the throttling devices. That is,the fluid flow can be judged by measuring the differential pressure.

Pressure measuring points 1 and 2 are set at appropriate positions ahead of and behind the throttling device.Given the throat diameter of the throttling element is d (mm),the inner diameter of the pipe D (mm),the area of the flow-passing section A, the velocity of the fluid on the flow-passing section V, the position height of the fluid h,the mass flow of the fluid Qm,and the density of the fluid under working conditions { ~ \rho ~ } ( {kg } / { m } ^ { 3 } ) ，the velocity and pressure parameters of the fluid on the two pressure measuring sections conform to:

Bernoulli's equation { ; ~ h _ { 1 } g + / { ~ P _ { 1 } ~ } { ~ \bf ~ \underline { { { p } } } ~ } _ { 1 } + / { ~ { \bf { v } } ~ _ { 1 } ^ { 2 } ~ } { ~ \bf ~ \underline { { { 2 } } } ~ } = h _ { 2 } g + ~ / { ~ P _ { 2 } ~ } { ~ \bf ~ \underline { { { p } } } ~ } _ { 2 } + / { ~ { \bf { v } } ~ _ { 2 } ^ { 2 } ~ } { ~ \bf ~ \underline { { { 2 } } } ~ } ~ }

Flow continuity equation: p { \bf \nabla } _ { 1 } \mathbf { V } _ { 1 } \mathbf { A } _ { 1 } = { \boldsymbol { ~ p ~ } } _ { 2 } \mathbf { V } _ { 2 } \mathbf { A } _ { 2 }

Where:C-discharge coefficient; β - diameter ratio of throttling device; ε-expandability coefficient

It can be seen from the equation that,when the orifice diameter of the throttling element is d and the fluid density \rho is constant,the flow and the static differential pressure \Delta { \mathfrak { p } } are in a square root relationship.The flow can be obtained according to the static differential pressure measured by the differential pressure meter. The flow coefficient in the equation is not derived from the theoretical equation,but is determined by considering the velocity distribution of the fluid in the flow-passing section and the energy loss of the fluid flowing through the throttling device, which depends on structure of the throttling device. For this reason,there are domestic and international manufacturing standards for the structure of throttling devices,and the throttling device is divided into two structural forms,i.e.standardand non-standard.

For the standard throttling device,it is assumed that the non-calibrated throttling device is similar to the fully calibrated throttling device in terms of geometry and dynamics.That is,the flowmeter meets all requirements of the standard document (GB/T2624 or IS05167),and its measurement accuracy is within the measurement error specified in the standard.The relationship between mass flow and differential pressure can be determined based on the above flow equation.The conditions for achieving geometric similarity mainly mean that the structural form of throttling device,the pressure tapping device,and the manufacturing and installation of the upstream and downstream straight pipe sections of the throttling element,etc.fully comply with the standard.The condition for dynamical similarity is equal Reynolds number.

Temperature and pressure compensation

Pressure and temperature are important parameters that affect the accuracy of flow measurement.Temperature and pressure compensation measurement is a method with which the fluid temperature and pressure are measured while the fluid flow is measured by the throttling device,and then the fluid density \rho at temperature T and pressure { ~ \bf ~ P ~ } is obtained based on the relationship between them,so that the fluid flow can be corrected.

General temperature and pressure compensation formula for throttling device

1.Liquid: In general, temperature and pressure have very small impact on the liquid density,so temperature and pressure compensation is generally not adopted for liquid.

2.Gas: Temperature and pressure changes generally have great impact on the gas density. Therefore,the gas generally needs temperature and pressure compensation.

Temperature and pressure compensation formula forgeneral gas:

Qcompensation: the flow after temperature and pressure compensation,in the unit as described in the calculation sheet

Qmeasurement: the flow measured according to the flow calculation formula in the calculation sheet, in theunitasdescribed in the calculation sheet

Pmeasurement: the actual pressure value measured on site,in Mpa

Ppressure:the atmospheric pressure of the applicationarea,inMpa

Pdesign: the design pressure value in the calculation sheet,in Mpa

Tmeasurement: the actual temperature measured on site,in ^ { \circ } { C }

Tdesign: the design temperature value in the calculation sheet,in ^ { \circ } { C } （204号

3.Steam: temperature and pressure compensation is necessary for superheated steam.Only temperature

compensation formula or pressure compensation formula is applicable to saturated steam,and pressure compensation is generally adopted.

Mcompensation: the flow after temperature and pressure compensation,in Kg/h

Mmeasurement:the flow measured according to theflowcalculation formulain the calculation sheet,in Kg/h

pactual: the density value of steam under on-site Working conditions,which is generally found in the data according to the working pressure and working temperature,and can also be estimated by referring to the empirical formula in case oflow requirements:

P1:working pressure (absolute pressure) in Mpa t:working temperature in ^ { \circ } { C } （204号 Remarks:The formula is applicable to a working temperature (t） range of 1 3 0 { ~ } 6 0 0 ^ { \circ } { C } ，and absolute pressure (P1) range of 0 . 3 { ~ } 5 { M P a } （204 pdesign:steam density in the calculation sheet, in { K g / m } ^ { 3 } （20

2.Characteristicsand Technical IndicatorsofThrottling Device

2.1 Features

1) Many media applicable to measurement and a wide range of working conditions 2)Mature technologyand good reliability 3) Standard manufacturing and good repeatability 4)Long service life and easy maintenance

2.2 Main technical indicators of throttling device

Throttling devices with the structural form and technical requirements specified in GB/T2624 (or ISO5167）are standard throttling devices,and others are non-standard throttling devices.The accuracy of standard throttling device is still within the measurement error specified in the standard without receiving the real flow calibration.

1)The uncertainty δ { { c / C } } in discharge coefficient of the standard orifice is as follows:

The uncertainty is ( 0 . 7 { - } β ) % when 0 . 1 { \le } β { < } 0 . 2

The uncertainty is 0 . 5 % when 0 . 2 { \le } { β } { \le } 0 . 6

The uncertainty is ( 1 . 6 6 7 β - 0 . 5 ) % when 0 . 6 { < } β { \le } 0 . 7 5

The above values shall be added arithmetically to the following relative uncertainty when { D } { < } 7 1 . 1 2 \ {mm } (2.8 in):

The above values shall be added arithmetically to the following relative uncertainty when β { > } 0 . 5 and { R e D } { < } 1 0 0 0 0 ：

（ { \Delta \ B } refers to the diameter ratio of throttling element)

2)The uncertainty δc/C in discharge coefficient of the standard nozzle is as follows;

The uncertainty is ± 0 . 8 % when β { <= } 0 . 6

The uncertainty is ( 2 β - 0 4 ) % when β { > } 0 . 6

中 { ^ { \small { ~ \mathscr { ~ } β ~ } } } refers to the diameter ratio of throttling element)

3)The uncertainty δc/C in discharge coefficient of the standard venturiisas follows:

Within the specified service limits,the relative uncertainty in discharge coefficient of the classical venturi tube is equal to:

- 0 . 7 % (for the classic venturi tube with cast
contraction section) 1 1 . 0 % (for the classic venturi tube with machined
contraction section) ， 1 . 5 % (for the classic venturi tube with rough

Chapter V Standard Orifice Differential Pressure Flowmeter

1.MeasurementPrincipleof Standard Throttling Element

The standard throttling element is designed, manufactured and used according to technical specifications such as the international standard ISO5167 and Chinese standard GB/T2624.Standard throttling elements include standard orifice,standard nozzle and standard venturi tube types.The standard orifice type is divided into angle joint pressure tapping type,flange pressure tapping type and radius pressure tapping type.The standard nozzle type is divided into ISA1932 nozzle type and long-radius nozzle type.

When the fluid filled in the pipeline flows through the throttling element (orifice type here),it will contract locally at the orifice,thus increasing the flow rate and reducing the static pressure.Therefore,a pressure drop will occur ahead of and behind the throttling element,i.e.a differential pressure.The greater the flow rate of the medium,the greater the differential pressure generated ahead ofand behind the throttling element.Therefore,the fluid flow can be determined by measuring the differential pressure. This measurement method is based on the principles of the flow continuity equation (law of conservation of mass) and the Bernoulli equation (law of conservation of energy).

The flow calculation formula of the orifice is derived from Bernoulli equation and continuity equation,which isas follows:

The calculation formula is as follows:

Where:
qm- mass flow ( {kg / s } ) 1
qv- volume flow ( { m } ^ { 3 } / { s } ) （204号
f-expandability coefficient
△P-differential pressure (Pa)
C-discharge coefficient
d-opening diameter of throttling element (m)
β -diameter ratio, { β } = { { d } } / { { D } } （204号
D-pipe inner diameter(m)
p1-measured fluid density ( {kg / m } ^ { 3 } )

The discharge coeficient refers to the actual flow through the device versus the theoretical flow determined for an incompressible fluid.It is represented by the following formula:

Notes:1.Calibration of a standard primary device with an incompressible fluid (liquid) shows that the discharge coefficient is only related to Reynolds number for a given primary device under a given installation condition.

For different primary devices,the C values are the same aslong as the devices are similarin geometry and the Reynolds numberof the fluid is the same.

GB/T2624 (all parts）gives equations for calculating C values based on experimentally determined data.

Calibrating flow under suitable laboratory conditions can reduce theuncertainty ofCvalue.

2.The quantity 1 / sqrt { 1 - β ^ { 4 } } is called the "asymptotic velocity coefficient"and the product / { 1 } { sqrt { 1 - β ^ { 4 } } } is called the "flow coefficient".

ε:Expandability coefficient Considering compressibility coefficient of the fluid:

Note:Calibration ofa given primary device with compressible fluid(gas) indicates that the value below

dependson the Reynolds numberaswell as the pressure ratio and isentropic index of the gas.

These variations are expressed by multiplying the expandability (expansion） coefficient ε by discharge coefficient C of the primary device.The discharge coefficient Cis determined through direct calibration using liquids with the same Reynolds value.

\scriptstyle { \varepsilon = 1 } for incompressible fluid (liquid),and \varepsilon { < } 1 for compressible fluid(gas).

Experiments show thatεis actually independent of the Reynolds number.ε only depends on the pressure ratio and the isentropic index for a given diameter ratio of a given primary device.Therefore, thismethodisfeasible.

Theε value of orifice given in GB/T2624.2 is based on the experimentally determined data.Theε values of nozzle (see GB/T 2624.3) and venturis tube (see GB/T 2624.4) are based on the general thermodynamic equations applicable to isentropic expansion.

2.MainCharacteristics ofOrifice

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Mainadvantages of orifice

It complies with the international standard IS05167 and national standard GB/T2624. Standardization is mainly performed to determine the relationship between differential pressure and flow without real flow calibration，and calculate the measurement error accurately with special software according to relevant experimental data results in the standard.

Note:A large number of calibration experiments, distribution range and quality are sufficient to make sure that relevant application systems can be based on the calibration experiment results and coeficients with certain predictable uncertainty limits (extracted from GB/T2624).

·Be suitable for media such as liquid,gas and steam;

·Be applicable to various working conditions such as high temperature,high pressure and ultra-low temperature.

·Have international standards and national standards to follow,a long history,and the most practical application experience.

·Do not have moving part,and have simple structure,stability and reliability;

·Low cost,and be easy to install and maintain.

Main disadvantages of orifice

1.High requirements for on-site installation,and long front and rear straight pipe sections

2.Great pressure loss.

3.The orifice throttling knife edge is easy to wear after long-term use,which affects the accuracy.

3.Basic Structure ofOrifice

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The orifice mainly has three pressure tapping modes:flange,radius(DandD/2) and angle joint. The typical structure is as follows.For flange pressure tapping,axial lines of the pressure tapping holes on the upstream and downstream sides of the throttling elementsarelocated 2 5 . 4 ~ {mm } from the front and rear end faces of the throttling elements respectively.

For radius pressure tapping (D and D/2), centerlines of the pressure tapping holes on the upstream and downstream sides of the throttling elementarelocated1D and1/2Dfrom the inlet end face respectively.

Angle joint pressure tapping is performed by drilling or in the annular chamber.For the orifice,the pressure tapping holes on the upstream and downstream sides of the throttling element shall be flush with the front and rear end faces of the throttling element.

Standardorifice

(I) Structure of throttling element

The structure of standard orifice is shown in the figure.

Notes:1.Angle joint pressure tapping includes pressure tapping by drilling and pressure tapping in annularchamber 2.d refers to the opening diameter,and D refers to the pipe inner diameter(in mm)

The flow throttling device consists of throttling elements,pressure tapping devices (including pressure tap,impulse pipe and valve),companion flanges and short process pipes.

1. Common angle joint pressure tapping orifice (pressure tapping by drilling,

00bo=

Exploded View ofDrillingPressure Tapping Orifice

三00e0030

Exploded View ofAnnular Chamber Pressure Tapping Orifice

2.Common flange pressure tapping orifice assembly(with a pressure <= 4 2 . 0 { { M P a } } diameter \le { D N } 6 0 0 ,and the maximumsize ofnon-standard orifice ofDN4000)

Exploded View ofRFFlange Pressure Tapping Orifice with Flat Sealing Face

Exploded View ofRJFlange Pressure Tapping Orifice with Trapezoidal Sealing Surface

3.Weldedorifice(withapressure <= 4 2 . 0 MPa,and diameterofDN25\~DN800)

Weldedorifice

Scope of application

The orifice can be used to measure single-phase fluids such as gas,liquid and steam.The fluid runs ata subsonic speed in the measurement section,and meets the following conditions:

The orifice is generally used to measure the unidirectional flow,but can also be used to measure bidirectional flow when the following conditions are met:

·The orifice shall notbe beveled. ·Each end face of the orifice shall comply with the provisions on upstream face in 5.1.3 ofGB/T2624.

·The orifice thickness E shall be equal to the orifice thickness e specified in5.1.5 ofGB/T2624,so it maybe necessaryto limit the differential pressure to prevent orifice deformation (see 5.123).

·Two edges of the orifice shall comply with the provisions on upstream edge in 5.1.7 ofGB/T2624.

Note:For orifice with radius pressure tapping mode (D and \scriptstyle { \mathbf { D } } / 2 ),upstream and downstream pressure tapping devices (i.e.two sets）shall be provided accordingto different flow directions.

Note: { D N } 2 5 { ~ } { D N } 5 0 shells and orifice are integrated,and are forged integrally with the same material.

4.Installation Dimension ofRFDrilling Pressure Tapping Orifice

5.Installation Dimension ofRFFlange Pressure Tapping Orifice

6.Installation Dimension ofRJFlange Pressure Tapping Orifice

7.Installation requirements

The fluid flows from upstream face to downstream face of the orifice.The orifice and the pipe must be concentric (or centered in the annular chamber),and the eccentric distance CX (the distance between the centerline of throttling element and the centerline of upstream and downstream pipes） shall not be greater than 0 . 0 0 2 5 { D } / ( 0 . 1 + 2 . 3 0 4 ) 0r 0.015D(1/β-1).

The pipeline in the measurement section must be filled with fluid.

If a regulating valve must be installed,it is recommended to install it behind the downstream 5D straight pipe section.

If an isolation valve must be installed upstream of the throttling element, the valve shall be a gate valve and must be fully open.

Packing and sealing rings shall be manufactured and installed so that they do not protrude into the inner cavity of pipe or obstruct the pressure tapping hole or groove at any point.

The packing (if any） between the throtling element or the annular chamber shall be as thin as possible and shall not protrude into the annular chamber cavity.

Throttling elements shall be embedded between two straight pipe sections with uniform cross section. The requirements for minimum straight pipe section length on the upstream and downstream sides of orifice are shown in the following table:

Chapter VI NozzleDifferentialPressureFlowmeter

1.MeasurementPrinciple ofNozzle

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2. CharacteristicsofNozzle

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The measurement principle of nozzle is based on the throttling principle of hydromechanics.When the fluid filled in the pipeline flows through the nozzle in the pipeline,it will contract locally in the nozzle,thus increasing the flow rate and reducing the static pressure.Therefore,a pressure drop or differential pressure will occur ahead of and behind the nozzle. The greater the medium flow,the greater the differential pressure generated ahead of and behind the nozzle.Therefore,the fluid flow can be determined by measuring the differential pressure.

The nozzle is of an arc-shaped profile structure, therefore,its pressure loss is small,the straight pipe section required is short and the precision is high.

Flow calculation formula:

The standard nozzle flowmeter is characterized by high temperature and high pressure resistance, impact resistance,long service life,large measuring range and high measurement accuracy.It is suitable for the measurement of high-speed fluid flow in hightemperature and high-pressure steam heating network pipelines of power plants.

The standard nozzle is designed and manufactured according to the national standard GB/T2624-2006(or ISO5167) and verified according to JJG640-2016.Standardization is mainly performed to determine the relationship between differential pressure and flow without real flow calibration,and estimate the measurement error accurately with special software.

·Simple structure and convenient installation. ·Smaller loss than that of orifice,and shorter straight pipe section required. ·Resistance to high temperature,high pressure and impact. ·High corrosion resistance and long service life. ·High precision,good repeatability and stable discharge coefficient. ·Adoption of integral forging(without welding) and integral numerical control processing technology with high cost.

Where:
qm-mass flow ( {kg / s } ) 0
qv -volume flow ( { m } ^ { 3 } / { s } ) 1
ε-expandability coefficient
\triangle \mathbf { P } - differential pressure (Pa)
C- discharge coefficient
d- opening diameter of throtling element (m)
β - diameter ratio, { β } = { { d } } / { { D } }
D-pipe inner diameter (m)
p1 - measured fluid density ( {kg / m } ^ { 3 } ) 2号

3.Structural FormofNozzle

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The standard nozzle consists of an inlet plane perpendicular to the axis,an arc-shaped curved surface,an inlet contraction part formed,a cylindrical throat and a protective groove required to prevent edge damage.It adopts the angle joint pressure tapping mode at the upstream and the downstream,or at a far downstream.

Product classification:annular chamber nozzle, welded nozzle and long-radius nozzle.

3.1 Nozzle (ISA1932)

(I) Structure of throttling element The nozzle structure is shown in the following
figure.
(II) Scope of application 5 0 { {mm } <= D <= 5 0 0 { {mm } } } 0 . 3 { \le } β { \le } 0 . 8 （204号 7 0 0 0 0 <= { R e D } <= 1 0 7 when 0 . 3 0 <= β < 0 . 4 4 2 0 0 0 0 <= { R e D } <= 1 0 7 when 0 . 4 4 <= β < 0 . 8 0 （204号

3.3Welded nozzle assembly

(I) Shell structure

The structure of welded nozzle is shown in the
following figure.
(II) Scope of application Pressure <= 4 2 . 0 MPa Diameter ofDN65\~DN1500

Welded nozzle

3.2 Annular chamber pressure tapping nozzleassembly

(I) Product structure The structure of annular chamber pressure tapping nozzle is shown in the following figure.

(II) Scope of application Pressure <= 1 0 . 0 { { M P a } } DiameterofDN40\~DN600

3.4Long-radius nozzle

(I) Structure of throttling element

Structure ofLong-radius Nozzle

The structure of long-radius nozzle is shown in the following figure. (II) Scope of application Diameter ofDN25\~DN600 0 . 2 { \le } { \underline { { { β } } } } { \le } 0 . 8 （20 104≤ReD≤107 Note:For special diameter,please refer to the quotation for selection.

FLOW 川

3.5.Radius pressure tapping long-radius nozzle assembly

(I) Shell structure

The radius pressure tapping long-radius nozzle consists ofan inlet contraction part,a cylindrical throat and a downstream end plane,and it adopts the D-D/2 radius pressure tapping mode.

There are two types of long-radius nozzles:

High ratio nozzle 0 . 2 5 { \le } β { \le } 0 . 8

Low ratio nozzle 0 . 2 5 { \le } β { \le } 0 . 5

Any type of long-radius nozzle can be adopted if thevalue of β is between 0.25 and 0.5.

(II) Advantages oflong-radius nozzle

The long-radius nozzle is mainly used for main steam,main feed water or desuperheating water in the power industry or high-temperature and high-pressure sites.It is characterized by wide range ratio,impact resistance,small pressure loss,long service life,large measuring range and high measurement accuracy.

It is designed and manufactured according to the national standard GB/T2624-2006(orISO5167);

and verified according to JJG640-2016,without real flow calibration.

^ { * 1 } .In order to ensure the measurement accuracy,the inner wall of measuring pipe of the longradius nozzle is processed by special equipment.

^ { * } 2 .In order to ensure the product safety,the long-radius nozzle measuring pipe and the positioning ringshall be integrally processed and formed,without circumferential welds.

^ { * } 3 ．The roughness of inner hole shall meet the nationalstandardGB/T2624.3-2006.

4.PrecautionsforInstallation

The installation shall ensure that the pipe is filled with liquid.

The impulse pipeline shall be installed according to the standard,with positive and negative pressure tapping points at the same level to prevent errors.

It shall be avoided from high-concentration corrosive gases in the surrounding environment as much as possible.

The nozzle flowmeter shall be installed to avoid negative pressure in the measuring pipe as much as possible.

The nozzle flowmeter shall be installed in a place with small vibration,especially for integrated instruments.

The nozzle flowmeter shall be installed downstream of the section where the reaction is fully completed during the measurement of chemical reaction pipeline.

Thenozzle flowmeter shall be installed without large motors,large transmitters,etc.nearby to avoid interference with the nozzle field.

StraightPipe SectionsRequired byNozzle and VenturiNozzle

Chapter VII StandardVenturiDifferential Pressure Flowmeter

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1. ClassicVenturi

Venturi tube isa differential pressure device for flow measurement.Its name comes from the Italian physicist G.B.Venturi who invented it.It consists of an equal-diameter inlet section,a contraction section,an equal-diameter throat and a diffusion section.Its measurement principle is as follows:when the fluid filled in the pipeline flows through the throttling elementin the pipeline,it will contract locally at throat neck of the venturi tube,thus increasing the flow rate and reducing the static pressure,and resulting in a differential pressure ahead ofand behind throat neck of the venturi tube.The greater the fluid flow,the greater the differential pressure generated,so that the flow can be determined based on the differential pressure.This measurement method is based on the flow continuity equation (law of conservation of mass） and the Bernoulli equation (law of conservation of energy).It is widely used for the flow measurement of air,natural gas,gas,water,steamand other fluids.

Venturi tube is a throttling flow sensor developed based on Venturi effect and is a standard throttling device.Venturi tubes are divided into standard type and general type according to the structure.

Standard(classic) venturi tubes are divided into the standard venturi tube with rough-cast contraction section,standard venturi tube with machined contraction section,and standard venturi tube with rough-welded iron plate contraction section according to their manufacturing methods.

The standard venturi is designed and manufactured according to the national standard GB/T2624-2o06,and verified according to the national standard JJG640-2016.

In addition to advantages such as high accuracy, good repeatability,small pressure loss and short front straight pipe required of the standard venturi tube,the general venturi series flow sensor also has the advantages of small size and anti-blocking performance.It can be used to measure complex flow such as two-way flow,mixed-phase flow,low flow rate,large pipe diameter and special-shaped pipe.

Venturi is divided into standard venturi,general venturi,venturi flow tube,small-diameter venturi, rectangular venturi and other structures according to the manufacturing process and purpose.

The flow calculation formula of venturi is derived from Bernoulli equation and continuity equation, which isas follows:

Where:

（20 { \bf q } _ { { m } } - mass flow (kg/s)
（204号 { \sf q _ { v } } ^ { = } volume flow ( { m } ^ { 3 } / { s } ) （204号
ε- expandability coefficient
\bigtriangleup \mathbf { P } - differential pressure (Pa)
C-discharge coefficient
{ { ~ d ~ . ~ } } opening diameter of throttling element (m)
β -diameter ratio, { β } = { { d } } / { { D } } （204号
D-pipe inner diameter (m)
（204 \rho _ { 1 } - measured fluid density ( {kg / m } ^ { 3 } ) 1

C:Discharge coefficient

It is a coefficient that represents the relationship between the actual flow through the device and the theoretical flow,and is determined for an incompressible fluid.It is represented by the following equation:

Notes:1.Calibration of a standard primary device with an incompressible fluid (liquid) shows that the discharge coefficient isonlyrelated to Reynolds number for a given primary device under a given installation condition.

For different primary devices,the C values are the same as long as the devices are similar in geometry and the Reynolds number of the fluid is the same.

GB/T2624 (all parts）gives equations for calculating C values based on experimentally determined data.

Calibrating flow under suitable laboratory conditions can reduce the uncertainty of C value.

2. The quantity \overline { { 1 sqrt { 1 - β ^ { 4 } } } } is called the "asymptotic velocity coefficient"and the product is { c } / { 1 } { sqrt { 1 { ~ - ~ } β ^ { 4 } } } called the "flow coefficient".

ε:Expandability coefficient Considering compressibility coefficient of the fluid:

Note:Calibration ofa given primary device with compressible fluid(gas) indicates that the value below

depends on the Reynolds number as well as the pressure ratio and isentropic index of the gas.

These variations are expressed by multiplying the expandability (expansion） coefficient ε by discharge coefficient C of the primary device.The discharge coefficient C is determined through direct calibration usingliquidswith the same Reynolds value.

\scriptstyle \varepsilon = 1 for incompressible fluid (liquid),and \varepsilon { < } 1 for compressible fluid (gas).

Experiments show thatεis actually independent of the Reynolds number.ε only depends on the pressure ratio and the isentropic index for a given diameter ratio of a given primary device.Therefore,this method is feasible.

The εvalue of orifice given in GB/T2624.2is based on the experimentallydetermined data.Theεvalues of nozzle (see GB/T 2624.3) and venturis tube (see GB/T 2624.4） are based on the general thermodynamic equations applicable to isentropic expansion.

2.CharacteristicsofVenturiTube

1.The classic venturi tube is designed and manufactured according to ISO5167-2003 and GB/T2624-2006,and does not need to be verified. 2.The front and rear straight pipe sections required by the venturi tube are short,and the shortest part can be 2.5D in front section and 1.5D in rear section. 3.The permanent pressure loss of venturi tube is small.Generally,the pressure loss is only about 1/8 of the differential pressure value.Its pressure loss is the minimum compared with other throttling devices (such as orifice,nozzles,etc.). 4.High stability,smooth differential pressure and high reliability. 5.It is an environment-friendly and energy-saving product with accurate calculation,low energy consumption and great energy saving. 6.It can be used for various dirty media such as liquid, gas,steam and two-phase flow. 7. It is a pure mechanical structure without rotating parts,and with simple structure,easy installation, convenient maintenance and long service life.

Main advantagesof venturi tube

·It complies with the international standard ISO5167 and national standard GB/T2624. Standardization is mainly performed to determine the relationship between differential pressure and flow without real flow calibration,and estimate the measurement error accurately.

·It is applicable to liquid,gas,steam and other media,and has greater advantages over other flowmeters inmeasuring high-temperature and high-pressure fluids;

·There are international standards and national standards to follow,the application history is long,and the practical application experience is the most;

·It has no moving part,but is structurally simple, stable and reliable:

·Among other standard throttling devices，it requires the shortest upstream and downstream straight pipe sections and the minimum permanent pressure loss.

·The calculation is accurate and energy consumption is low.

·It can be used for various dirty media such as liquid, gas, steam and two-phase flow.

·The standard venturi body is longer,which is about 2\~5 times the pipe diameter (determined by the ratio of venturi opening diameter).

Maindisadvantagesofventuritube:

·High manufacturing requirements ·High material and manufacturing costs.

3.StructureofVenturi Tube

The venturi tube generally adopts grading ring for pressure tapping (single or two pressure taps are also used for the measurement of high-pressure medium), with the typical structure shown as follows:

Structure Drawing of Classic Venturi Tube

The length of venturi is calculated by the national standard formula,which has a direct impact on the β value.The following is an example in case of diameter DN100 and different β values.

4.ApplicationScope of Venturi Tube

The venturi tube can be used to measure singlephase fluids such as gas,liquid and steam.The flow runs at a subsonic speed in the measurement section.The venturi tubes are generally divided into three types,i.e. cast type,machined type,and rough-welded iron plate type,based on their manufacturing methods.The application scope of standard venturi tubes is related to the manufacturing method.

The application scope of qualified venturi tubes depends on the manufacturing method.

1.The application scope of venturi tube with roughcast contraction section is as follows: 1 0 0 { {mm } <= D <= 8 0 0 { {mm } } } （204号 0.3≤β≤0.75 2 x 1 0 ^ { 5 } { \le } { R e D } { \le } 2 { x } 1 0 ^ { 6 } （204号 2.The application scope of venturi tube with machined contraction section is as follows: 5 0 {mm } { \le } { D } { \le } 2 5 0 {mm } （204号 0.4≤β≤0.75 2 x 1 0 ^ { 5 } { \le } { R e D } { \le } 1 0 ^ { 6 } 3.The application scope of venturi tube with rough welded iron plate contraction section isas follows: 2 0 {mm } { <= } { D } { <= } 1 2 0 0 {mm } （20 0.4≤β≤0.7 2 x 1 0 ^ { 5 } \le { R e D } \le 2 x 1 0 ^ { 6 } Note:If the above parameters are exceeded,nonstandard design can be carried out. RT will be carried out randomly to ensure product welding quality.

5. Installation Requirementsfor VenturiTube

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Fluid flows from inlet section to diffusion section of the venturi tube.The venturi tube must be installed coaxially with the pipeline,and the non-concentricity shall be within ± 1 ^ { \circ } ：

The pipeline in the measurement section must be filled with fluid.

If a regulating valve must be installed,it is recommended to install it behind the downstream 5D straight pipe section.

If an isolation valve must be installed upstream of the throttling element,the valve shall be a gate valve and must be fully open.

The sealing ring shall not protrude into the inner cavity of pipeline or block the pressure tap or groove.

Throttling elements shall be embedded between two straight pipe sections with uniform cross section.The requirements for minimum straight pipe section length on the upstream and downstream sides of venturi tube are shown in the following table:

StraightPipeSectionsRequiredbyClassicVenturiTube

Values expressed in multiples of the pipe inner diameter D

Notes:1.The shortest straight pipe section required is the section between various pipe fitings upstream of the classc venturi tube and the classic venturi tube.The straight pipe section shallbe measured from the downstream end of the nearest (or only) elbow curved portionor from the downstream end of the curved or conical portion of the reducing or diverging pipe to the upstream pressure tap plane of the classic venturi tube.

2.The thermometer pocket or thermowell(if any) fitted upstream of the classic venturi tube shall have a diameter not exceeding O.13D,and be located at least 4D upstream of the upstream pressure tap plane of the venturi tube.

3.For downstream straight pipe section,pipe fitings or other chokes (as shown in this table）or densitometer pockets located at least 4 times the throat diameter downstream of the throat pressure tap plane shall not affect the measurement accuracy.

a.Theradius of curvature of elbow shall be greater than or equal to the pipe diameter. b.Column Aof various pipe fittings gives a value corresponding to "zero additional uncertainty". c .Column B of various pipe fitings gives a value corresponding to " 0 . 5 % additional uncertainty". d.Zero additional uncertainty is given for the straight pipe section in column A,and there is currently no shorter straight pipe section data available to give the straight pipe section required in column B.

ChapterVIII Non-standard ThrottlingElement

Non-standard throttling elements are not designed,manufactured orused in full accordance with the international standards ISO5167 and technical specifications GB/T2624.Non-standard throttling elements include double orifice,notched orifice,1/4 round nozzle,V-shaped inner cone types,etc.

2. Segmental orifice plate

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(I) Structure of throttling element

1.LowReynoldsNumber ThrottlingElement

Low Reynolds number throttling elements include conical inlet orifice type and 1/4 round orifice type.

(I) Structure

Segmental orifice plate

1/4 round orifice plate Conical inlet orifice plate

(II)Features

Itisapplicable to medium and small diameter, low flow rate and high viscosity fluids.

(III) Application conditions Conical inlet orifice: 25mm≤D≤500mm 0.1≤β≤0.316 8 0 { <= } { R e D } { <= } 2 { x } 1 0 5 β 1/4 round orifice: d≥15mm D≤500mm 0.245≤β≤0.6 245≤ReD≤105β

(II)Features

The fluid is disturbed forcibly by the throttling element,which is conducive to measuring the dirty medium.

(III) Applicable pipe diameter 5 0 {mm } { \le } { D } { \le } 1 6 0 0 {mm } （20 0.3≤β≤0.8 ReD>10000

3.OtherThrottlingDevices M

PTFE restriction orifice

PTFEbuilt-in orifice

Integrated pipe orifice(two pairs of pressure taps)

Anti-corrosion wedge flowmeter

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PVCorifice <br>Corrosion-resistant balanced multi-hole

SIC New Generation DFYT-type Integrated Orifice Flowmeter

1. ProductIntroduction

2.ProductFeatures

The integrated orifice flowmeter consists of integral orifice (which can be replaced separately), three-valve manifold and differential pressure transmitter,clamping flange,process connecting flange,straight pipe section (optional) and other main components.Users can use it by only connecting a flowindicator.It will be a complete flowmeter if the transmitter is replaced with a multi-parameter transmitter,and will have the temperature and pressure compensation function if equipped with thermal resistance or thermocouple.Due to the overall design and manufacturing,the straight pipe section is processed by drilling and boring,with high processing accuracy,and with smaller dimensional error and roughness compared with the straight steel pipe section.The orifice,straight pipe section and flange are positioned coaxially,and high-quality transmitters are selected.Real flow calibration ofcoefficient can be performed after the overall pressure test before leaving the factory,so that the integrated orifice flowmeter has outstanding advantages such as simple installation and maintenance,high positioning accuracy,high measurement accuracy,stable and reliable performance,etc.It is more and more widely used, especially in the flow measurement of small-diameter pipelines.

·Integrated differential pressure flow measurement system

Primary element is integrated with differential pressure transmitter to become a single flowmeter

·Integrated flowmeter,which is used for overall
pressure test of elbow assembly ·Higherreliability,no leakage ·Mass flow signal,equipped with integrated
temperature measuring element ·Integrated multivariable transmitter and
temperature measuring element,only one set is
required to read the gas mass and corrected volume
flow directly ·Integrated pressure connection ·No impulse pipeline is required ·Reusable differential pressure connections are
provided throughout the installation site ·Lower installation cost ·Only one-piece installation is required ·It is unnecessary to provide or connect
manifold,transmitter and impulse pipeline separately

Flange Clamped Integrated orifice plate

Flange Clamped Integrated orifice plate

Integrated Orificewith Thermal Resistance Compensation and CondenserIntegrated orifice plate

3.ProductAdvantages

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·Integration:Which reduces the installation cost

·Integrated transmitters,manifolds,and pressure taps are designed to eliminate the need for impulse pipeline and have the following advantages:

- Ensure higher positioning and installation accuracy of pressure taps -Reduce the likelihood of blockage of impulse pipelines ·Minimum pressure loss,highest measurement accuracy and optimal measurement dynamics ·Measurement method complying with ISO 5167 international standard ·Symmetrical orifice structure,which can be used for bi-directional measurement ·Solid instrument structure,and no movable part ·Differential pressure transmitters and valve manifolds installed in factory and specially configured ·Comprehensive leakage test and configuration completed in the factory

4. Structural Form Diagram

Comparison of Process Connection Characteristics ofDFYT-type Integrated Orifice

Temperature and Pressure Compensation Integrated Pipe-type Multi-hole

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Process Connection:A/B

Process Connection:E/F

Process Connection:H/I

5.ProductApplications

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·Gas,natural gas and steam measurement:with full compensation (differential pressure,pipeline pressure and temperature measurement);

Saturated steam:with differential pressure and pipeline pressure or differential pressure and temperaturemeasurement;

Liquids:with differential pressure and temperature measurement.Liquids at stable temperature:withdifferential pressuremeasurement.

茸

6.Maintechnicalparameters

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7.Overall Dimensions

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·Structural dimension of orifice sheet

Standard Orifice Structure

·Overall dimensions of orifice clamping flange

直

吉

直

SocketWelding Flange

·Schematic Diagram of Type B Structure with Temperature and Pressure Compensation and Condenser

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Integrated Orifice Structure with Thermal Resistance Compensation

Integrated Orifice with ThermalResistance Compensation and Condenser with Thermal Resistance Compensation

·Schematic Diagram ofH-shaped Structure with Front and Rear Straight Pipe Sections and Temperature and Pressure Compensation

Fig.A Fig.B

Note:The flange structure type is determined by the specific type selection.

\* Refer to Page PO3 for the type spectrum

8.Remarks

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Such high-performance differential pressure transmitter is used to measure the level,density,and pressure of liquid,gas,or steam.It can also be used to measure the differential pressure and static pressure accurately,show them on the multi-function LCD,and monitor them remotely through digital communication. BRAIN,HA RT,and FOUNDATION Fieldbus communication protocols are available.

SICNewGenerationDFPH-typeMulti-hole Orifice (BalancedOrificeFlowmeter)

1.ProductIntroduction

The multi-hole balanced orifice flowmeter is a third-generation throttling device,with a measurement accuracy 5\~1O times that of the traditional throttling device,a flow noise reduced to 1/15,a permanent pressure loss of about 1/3,a pressure recovery increased by 2 times,the minimum straight pipe section of 1D,and without moving parts.Its installation and use are very convenient and simple,so that long straight pipe sections are unnecessary,and the energy consumption required for fluid operation is reduced greatly.Therefore,it is an energy-saving instrument with bright application prospects.

Application

·Measure the flow of gas,steam and liquid ·Balance the flow field,reduce vortex,vibration and signal noise,and improve stability of the flow field greatly ·Ensure the smooth passage of dirty media with the multi-hole and symmetrical design,and measure Various dirty media,such as coke oven gas,blast furnace gas,residual oil,recycled oil,coal water slurry, etc.

·Be suitable for extremely low temperature fluids and prevent gasification effectively

Advantages

Effective measurement of any clean or dirty fluid

Liquid,gas,steam,multi-phase flow High and low temperature fluids Vapor-liquid two-phase,slurry ·Balanced rectification of the flow field ·Bi-directional flow measurement ·Extremely short upstream and downstream pipelines,which shall be at least 3D in the front section and 2D in the rear section ·High accuracy,which is within 1 % of indication ·Wide measuring range up to 3:l to 10:1 ·Multi-hole symmetrical design,resistance to dirt and low risk ofblockage ·Integrated structure,which is easy to use, check and troubleshoot