BS ISO 6358-2:2019

This document specifies a discharge test and a charge test as alternative methods for testing pneumatic fluid power components that use compressible fluids, i.e. gases, and that have internal flow passages that can be either fixed or variable in size to determine their flow-rate characteristics.

This document specifies a discharge test and a charge test as alternative methods for testing pneumatic fluid power components that use compressible fluids, i.e. gases, and that have internal flow passages that can be either fixed or variable in size to determine their flow-rate characteristics. However, this document does not apply to components whose flow coefficient is unstable during use, i.e. components that exhibit remarkable hysteretic behaviour (because they can contain flexible parts that deform under the flow) or that have an internal feedback phenomenon (such as regulators), or components that have a cracking pressure such as non-return (check) valves and quick-exhaust valves. In addition, it does not apply to components that exchange energy with the fluid during flow-rate measurement, e.g. cylinders, accumulators. NOTE This document does not provide a method to determine if a component has hysteretic behaviour; ISO 6358-1 does provide such a method.Table 1 provides a summary of which parts of the ISO 6358 series can be applied to various components. Table 1 Application of the ISO 6358 series test methods to components Components Constant

upstream pressure test Variable

upstream pressure test

constant upstream pressure test charge test

variable

upstream pressure test discharge
test Group 1 Directional control valves yes yes yes yes Flow control valves yes yes yes yes Connectors yes yes yes yes Valve manifolds yes yes yes yes Group of components yes yes yes yes Group 2 Filters and lubricators yes no no no Non-return (check) valves yes no no no Quick-exhaust valves yes no no no Tubes and hoses yes no no no Group 3 Silencers and exhaust oil mist separators no no yes yes Blow nozzles no no yes yes Cylinder end heads no no yes yes The charge test cannot be performed on components that do not have downstream port connections.This document specifies requirements for the test installation, the test procedure, and the presentation of results.Evaluation of measurement uncertainties is described in Annex A. Requirements for a method to test the volume of an isothermal tank are given in Annex B. Guidance on the isothermal tank is given in Annex C. Requirements for a method to test isothermal performance are given in Annex D. Guidance on the formula for calculating characteristics is given in Annex E. Guidance on calculating flow-rate characteristics is given in Annex F.