ISO 14540 -Dimensions and requirements for screw-to-connect quick-action couplings for use at a pressure of 72 MPa
Screw-to-connect quick-action couplings conforming to this International Standard are designed o join or separate fluid conductors ensuring, at the same time, sufficient resistance and safety in applications characterized by very high working pressures up to 72 MPa.
ISO 14540 specifies dimensional and performance requirements for hydraulic screw-to-connect quick-action couplings designed to be used at a pressure of 72 MPa in static conditions as an interface between a hydraulic power unit and a tool.
Typical applications for these couplings are related to hydraulic jacks, rams, clamping devices, hand tools, and cylinders.
This International Standard covers two types of such couplings: the “P” type, which has a poppet valve, and the “S” type, which has a spherical valve.
- a The shape of the valve is optional; “P” type version (with poppet valve) is shown
b The shape of the valve is optional; “S” type version (with spherical valve) is shown
c Use dimension D4, unless the valve is spherical
- d Maximum valve travel against stop.
e ealing diameter.
All dimensions and shape after L1 and D1 are left to the manufacturer
|a Size designation corresponds to the nominal hose size of the recommended hose; see ISO 4397.
b Use dimension D4 unless the valve is spherical
c In accordance with basic dimensions and formulae given in ISO 725 and ISO 5864, tolerance class 2A. See Annex A for the dimensions of the 1-18 UNS thread.
Couplings conforming to this International Standard shall meet or exceed the performance requirements specified in Table.
|Performance parameter||6.3 (1/4")||10 (3/8")|
|Working pressure b||72 MPa (720 bar)|
|Minimum burst pressure (coupled) c||216 MPa (2160 bar)|
|Minimum burst pressure for the "P" type (uncoupled) c||216 MPa (2160 bar)|
|Minimum burst pressure for the "S" type (uncoupled) c||144 MPa (1440 bar)|
|Rated flowd d||12 l/min||23 l/min|
|Maximum pressure drop at rated flow d||300 kPa (3 bar)||450 kPa (4,5 bar)|
|Maximum fluid loss per disconnection e||0,5 ml||1 ml|
|Maximum residual static pressure for connection e||10 MPa (100 bar)|
|a Size designation corresponds to the nominal hose size of the recommended hose; see ISO 4397
b The working pressure shall be verified in both the coupled and uncoupled conditions by pressure impulse testing for 10 000 cycles at the working pressure (low-cycle fatigue test) using the test pressure waveform specified in ISO 7241-2.
c The burst pressure shall be verified by testing in both the coupled and uncoupled conditions in accordance with ISO 7241-2
d The pressure drop at rated flow shall be verified by testing in accordance with ISO 7241-2.
e The fluid loss per disconnections hall be verified by testing in accordance with ISO 7241-2.
f Internal residual static pressure present in one coupling half.
Manufacturers of couplings conforming to this International Standard shall give proper written information to the customer about safety, correct use, best practice, and maintenance in order to allow correct and safe use of the products.
Couplings conforming to this International Standard are subject o very high internal pressure. The final user shall always use the most suitable protection devices when using the product and shall keep out of the product’s range of action.
Couplings conforming to this International Standard are not designed to be connected and disconnected under working pressure. However, the Table provides information about the maximum residual static pressure, which is present in one half only, that is allowable for connection.
Couplings of the “S” type, which have a spherical valve, are not preferred for applications that require that the coupling be pressurized in the disconnected condition.
Basic dimensions of the 1-18 UNS inch screw thread
Dimensions for 1-18 UNS, class 2A, inch screw threads (external)
|Thread||Allowance||Major diameter||Pitch diameter||Minor diameter|
Dimensions for 1-18 UNS, class 2B, inch screw threads (internal)
|Thread||Minor diameter||Pitch diameter||Major diameter|