GB/T 14513-1993Pneumatic fluid power -- Determination of flow-rate characteristics of components using compressible fluids -- Part 1: General rules and test methods for steady-state flow (English PDF)

Foreword

GB/T 14513 "Determination of the flow characteristics of compressible fluid components using pneumatic" is divided into the following three parts.

--- Part 1. General rules and test methods for steady-state flow;

--- Part 2. Alternative test methods;

--- Part 3. Calculation of steady-state flow characteristics of the system.

This section GB/T 14513 Part 1.

This section drafted in accordance with GB/T 1.1-2009 given rules.

This Part replaces GB/T 14513-1993 "Determination of flow characteristics of pneumatic components," compared with GB/T 14513-1993 main technology the changes are as follows.

--- Modify the "flow characteristics of pneumatic components" determination (see Chapter 1, 1993 edition Chapter 1);

--- In the "normative references", modify and add some references (see Chapter 2, 1993 edition Chapter 2);

--- In Terms and Definitions, the terms and definitions have been modified and added (see Chapter 3, Chapter 3 of the 1993 edition);

--- Added "subsonic index m, cracking pressure deltapc" 2 characterization parameters to describe the plug flow and subsonic flow area gas flow Dynamic performance (see 3.4.5, 3.4.6, 6.3.2.1, 6.3.2.2, 6.3.2.3);

--- Modify and add symbols and units (see 4.1, Table 2, Table 3, 1993 edition 4.1, 4.2, Table 1, Table 2);

--- Modify the test device test circuit diagram (see Figure 1, 1993 version of Figure 1); added "upstream pressure change test test Loop "(see Figure 2);

--- Added "test circuit components shown in Figure 1 and Figure 2" (see Table 4);

--- Removed the "connection of the device under test" (see 1993 version 5.2);

--- Deleted about the "gas content" (see 1993 version 5.3);

--- Removed the "air filter" (see 1993 version 5.4);

--- Removed the "test instrumentation" (see 1993 version 5.5);

--- Added "General Requirements" (see 5.3);

--- Added "pressure measuring tube" (see 5.4);

--- Added "adapter" (see 5.5);

--- Added "special requirements" (see 5.6);

--- Modify the "test conditions" (see 6.1, 1993 version 6.1);

--- Modify the "test procedure" (see 6.2, 1993 version 6.2);

--- Modify the "characterization" (see 6.3, 1993 version 6.3);

--- Modify the "test result expression" (see Chapter 7, 1993 edition Chapter 7);

--- Added "label instructions" (see Chapter 8);

--- Added "alternative test procedures" (see Appendix A);

--- Added "flow meter calibration" (see Appendix B);

--- Added "Measurement Uncertainty Assessment" (see Appendix C);

--- Added "observation of the error in the test results" (see Appendix D);

--- Added "expression of flow characteristics of the formula and graphics" (see Appendix E);

--- Added "actual use of units" (see Appendix F);

--- Added "expression of commercial pneumatic components test results" (see Appendix G);

--- Added "Using the solver function in Miscrosoft Excel to calculate the critical back pressure ratio b and the subsonic speed finger Number m "(see Appendix H).

This section uses the translation method is equivalent to using ISO 6358-1:2013 "Determination of the flow characteristics of compressible fluid components using pneumatic drives Part 1. General rules and test methods for steady-state flow ".

The documents of our country that are consistent with the corresponding international documents that are normative references in this section are as follows.

--- GB/T 786.1-2009 Fluid power systems and components Graphical symbols and circuit diagrams Part 1. For general use and number According to the processing of graphic symbols (ISO 1219-1:2006, IDT);

--- GB/T 7307-2001 Non-threaded sealing pipe thread Part 1. Dimensions, tolerances and labeling (eqvISO 228-1.

1994)

--- GB/T 17446-2012 fluid transmission systems and components vocabulary (ISO 5598:2008, IDT);

--- GB/T 28783-2012 Pneumatic standard reference atmosphere (ISO 8778:2003, IDT);

--- Pneumatic connection port and stud end (ISO 16030:2001/Amd.1.2005, IDT) --- GB/T 14038-2008;

For ease of use, this section made the following editorial changes.

--- Standard name changed to "Pneumatic components using compressible fluid flow characteristics of the first part of the steady flow of general rules and test methods ";

--- Correct a small number of editorial errors in ISO 6358-1:2013, change "GUM.2000" in Appendix C.1 to "GUM." 2008 ".

This part is proposed by China Machinery Industry Federation.

This part of the National Hydraulic Pneumatic Standardization Technical Committee (SAC/TC3) centralized.

This section is responsible for the drafting unit. National Pneumatic Product Quality Supervision and Inspection Center.

This section participates in the drafting unit. Ningbo Xingjian Aerospace Machinery Co., Ltd., Beijing University of Aeronautics and Astronautics, Wuxi Institute of Aerodynamic Technology Limited Company, Wenzhou Aerbe Pneumatic Co., Ltd., a constant pneumatic Co., Ltd., Zhejiang Braun Pneumatic Technology Co., Ltd., Zhejiang hydraulic pneumatic Seal Industry Association.

Introduction

In a pneumatic system, the pressure is passed through the circuit to transfer and control the energy. The components that make up the loop are inherent to the airflow Therefore, it is necessary to define and determine its flow characteristics to describe their performance.

ISO 6358:1989 is based on a shrink nozzle model developed to determine the flow characteristics of pneumatic valves. This method includes Two characteristic parameters, velocity-of-flow conductance C and critical pressure ratio b, are used for the recommended numerical approximation of flow characteristics. The method is based on static pressure the test results describe the flow characteristics of pneumatic valves ranging from plug flow to subsonic flow. The new version of ISO 6358-1:2013 test Taking into account the influence of the gas flow rate on the pressure measurement, stagnation pressure is used instead of the original static pressure.

Experience has shown that many pneumatic valves with shrinkage-expansion characteristics do not kiss well with models in the ISO 6358:1989 standard Together In addition, pneumatic components other than pneumatic valves also need to apply this standard. However, for the choke and subsonic flow zones, it is now required to use four parameters (C, b, m and deltapc) to define the flow performance.

This section describes the four sets of flow characteristics obtained from the test results. These parameters are descending according to their priority order Described below.

The sonic velocity guide C is the most important parameter which corresponds to the maximum flow rate (choke flow). This parameter is determined by the upstream stagnation condition.

The critical back pressure ratio, b, represents the demarcation point between the plug flow and the subsonic flow, which is the second most important parameter. It's defined as before the critical pressure ratio in ISO 6358:1989 is different because it characterizes the ratio of downstream stagnation pressure to upstream stagnation pressure.

Subsonic velocity index m, when necessary, can more accurately represent the subsonic flow behavior. For fixed flow channel components, m value About 0.5 or so. In this case, we only need to use C and b two characteristic parameters. For other components, m varies widely.

In these cases, you need to determine the C, b, and m values.

deltapc is the cracking pressure. This parameter applies only to those pneumatic components that open with increasing upstream pressure, such as check valves and check valves.

In order to overcome the apparent violation of the theory of compressible fluids, this section made some changes to the test equipment. Including increased intake pressure the measuring tube satisfies the assumption of neglecting the speed of the inlet during the test and allows direct measurement of the pressure at the inlet. Increase outlet measurement Tube used to directly measure the downstream stagnation pressure to meet the different pneumatic components. The difference between upstream and downstream stagnation pressures in the component means the pressure energy Loss.

In order to test components with larger nominal diameters, as well as shorten test times or reduce energy consumption, apply ISO 6358-2:2013 Specified methods, including deflation test and inflation test two alternative test methods.

Combined with GB/T 14513 of this part or ISO 6358-2:2013 obtained any of the components and pipe flow characteristics of the parameters, ISO 6358-3:2013 can be measured without the use of components and pipelines to calculate the overall flow characteristics of an estimated parameter Calculated.

It should be noted that the performance parameters obtained according to this part of the test and the performance parameters measured according to ISO 6358:1989 are different.

Pneumatic Flow using compressible fluid components Determination of characteristics - Part 1. steady state flow General rules and test methods

1 Scope

GB/T 14513 provisions of this part of a compressible fluid (eg, gas) test element flow characteristics under steady flow Methods.

This section applies to a fixed or variable internal flow of pneumatic components.

This section does not apply to the use of flow coefficient instability of the components, for example, showing obvious hysteresis components (because they Including elastic parts that can deform during flow) or components with internal feedback (such as pressure regulators). In addition, this section also Does not apply to the fluid flow measurement process energy exchange components, such as cylinders, accumulators and so on. See Table 1 for details.

Table 1 GB/T 14513 test methods in a variety of components in the application

element

The test for stable upstream pressure is used for the test of variable upstream pressure GB/T 14513.1 steady state the upstream pressure test ISO 6358-2 Inflatable test GB/T 14513.1 variable the upstream pressure test ISO 6358-2 Deflate test First group Directional control valve yes yes yes yes Flow control valve yes yes yes yes Yes, yes, yes Valve Group Yes Yes Yes Component Group Yes Yes Yes Second Group Filters and lubricators Yes No No No Check valve (check valve) Yes No No No Tube and hose Yes No No No the third group Silencer and exhaust mist Splitter no No Yes Yes Air No No Yes Yes Quick exhaust valve No No Yes Yes Cylinder and end cap No No Yes Yes this section specifies the test device for steady-state test methods, test procedures and the results expressed requirements.

This section includes several test procedures, including a method given in Appendix A, which comes from ISO 6358:1989. Appendix B Describes flowmeter calibration. Appendix C describes the evaluation of measurement uncertainty. Appendix D describes the error observed in the test results. Appendix E the equations and graphical expressions of the flow characteristics are given. Appendix F shows the actual usage of the unit in the presentation of results. Appendix G gives for the commercial pneumatic components test results. Appendix H gives guidelines for calculating flow characteristics.