1 Scope
This part of ISO 6358 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 part of ISO 6358 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, etc.
NOTE This part of ISO 6358 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 ISO 6358 can be applied to various components.
Table 1
—
Application of ISO 6358 test methods to components
|
Components
|
Constant
upstream pressure test
|
Variable
upstream pressure test
|
ISO 6358‑1
constant upstream pressure test
|
ISO 6358‑2
charge test
|
ISO 6358‑1
variable
upstream pressure test
|
ISO 6358‑2
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 |
| 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 |
| Quick-exhaust valves |
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 part of ISO 6358 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 equation for calculating characteristics is given in Annex E. Guidance on calculating flow-rate characteristics is given in Annex F.