What is a Push-On Fitting?

What is a Push-On Fitting?

A push-on is a type of ‘easy-fit’ fitting. They can be recognised from a central metal tube, over which the plastic pipe fits and a knurled nut tightened to retain the pipe. They can operate up to a pressure of 15 bar.

They are also known as...

Sometimes they can be referred to simply as push fittings; however, care must be taken as this can also refer to push-in fittings, where the pipe is retained by a grab ring, rather than the mechanism described below.

How do push-on fittings work?

The pipe is pushed over a barbed end of the central tube in the fitting, to a stop and then secured by tightening down a knurled nut onto the pipe and barb assembly. It is important to make sure that the plastic pipe is cut square and to remember to place the nut over the pipe before final assembly. The knurled nut is screwed until finger tight; the hexagon on the nut is to aid release.

How do I select a push-on fitting?

As with all system designs, piping and fittings should be selected to allow the necessary flow without undue pressure drop; all necessary fitting shapes should be available from the range for a particular application. Other important considerations are:

• working pressure

• working temperature - increasing temperature will reduce the operating pressure of nylon and polyurethane tubing

• working environment - both possible contaminants and ease of access for construction and maintenance

• construction and maintenance - any approvals required for the application, for example, use in the Food Industry

Types of compression fitting?

Across the ranges, all standard shapes are available to complete a system design, both metric and imperial: 

• variety of straight adaptors

• bulkhead connectors

• elbow connector and adaptors

• variety of tee connector/adaptors

• cross connector

• banjo connector

All work on the mechanical principle of connection outlined above.

Typical applications for push-on fittings?

The corrosion resistance, good pipe grip due to design and precision machining and ability to operate in confined spaces where tight radii are required, lend themselves to several applications. Some examples are:

• automation

• cooling

• applications involving inert gases

• vacuum

They are also suitable for many general compressed air applications.

Do I need anything else for push-on fittings?

Piping will be required for the connections to be completed; polyurethane and polyamide is suitable, and the fittings allow the use of extra flexible grades. For any new system designs additional components, such as air preparation, actuators and valves will also be required.

Visit our Fittings section to find out more.