GB/T 40565.4-2021Connections for hydraulic fluid power. Quick-action couplings - Part 4: Screw connection type at 72 Mpa (English PDF)

3.1 fluid loss

Fluid loss refers to the amount of fluid that leaks when the quick-action couplings are disconnected.

3.2 residual static pressure

shall comply with the stipulations of ISO 18869.

5.7 The quick-action couplings shall ensure that either end can be connected under a residual static pressure of 10 MPa, and pass 100 connection durability tests under this pressure without functional damage. The test method shall comply with the stipulations of ISO 18869.

6 Precautions

6.1 The manufacturer of the quick-action couplings conforming to this document shall provide appropriate written instructions to provide users with information on safety, correct operation and maintenance, so as to ensure the correct and safe use of the products.

6.2 The quick-action couplings conforming to this document are subject to extremely high internal pressure, hence, the user shall always use the most suitable protective device when applying the products, and reserve a safe working area for the products.

6.3 The quick-action couplings designed in compliance with this document are not allowed to be connected or disconnected under the working pressure. The stipulations of Table 2 only allow connections at one end with the highest residual static pressure.

6.4 The Type-S quick-action couplings with spherical valve are not applicable to pressurization in the disconnected state.

7 Identification The couplings conforming to this document are identified as follows:

a) “quick-action couplings”;

b) Serial No. of this document “GB/T 40565.4” and space character “-”;

c) Specifications and space character;

d) Type of quick-action couplings: Type-P with poppet valve or Type-S with spherical valve.

Example: hydraulic quick-action couplings that comply with this document and have a specification of 6.3 and Type-P poppet valve are identified as follows: quick-action couplings GB/T 40565.4-6.3-P.

8 Marking The quick-action couplings conforming to this document shall at least be permanently marked with the manufacturer’s name, trademark or product identification.