// Catalogue

Check Valves for Inline, Cartridge and Pilot-Operated Valves

Check valves let flow pass in one direction and block it in the other, protecting pumps, holding loads and keeping parts of a circuit apart. TSA Hydraulics Engineering supplies them within the Pressure & Flow family of our Valves range, for hydraulic oil, compressed air and water.

The spring inside is the detail most people miss. Check valves come with cracking pressures from a fraction of a bar up to several bar, and the wrong spring can starve a pump’s suction or upset a pilot circuit. Send the size, thread and cracking pressure stamped on the body. We will supply a factory original or an equivalent, sent from Sydney.

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// Buying guide

How a Check Valve Works

A ball, poppet or disc sits against a seat, held there by a light spring and by back pressure. When the pressure on the inlet side beats the spring, the valve opens and flow passes. When flow tries to reverse, the seal is pushed back onto its seat and the valve closes.

Cracking Pressure Matters

Very low, around 0.1 to 0.5 bar: suction lines and return lines, where any extra loss hurts.
Medium, around 1 to 5 bar: back pressure checks that keep enough pressure for pilot operated valves to shift.
Higher settings: bypass checks around filters and coolers, which open only if they block.

Always replace a check valve with one of the same cracking pressure, unless you know exactly why it should change.

Types of Check Valve

Inline: threaded ports, fitted straight into a pipe or hose.
Cartridge: screws into a manifold cavity. Common on power units and mobile machines.
Right angle: inlet and outlet at 90 degrees.
Modular: a sandwich valve stacked under a directional valve, often with checks on the A and B ports.
Pilot operated: holds flow back until a pilot signal opens it.
Swing and ball checks: larger, low pressure valves for water and process lines.

Pilot Operated Checks for Load Holding

A pilot operated check valve holds a cylinder firmly in place with almost no leakage. When the directional valve sends pressure to the other side, a pilot line lifts the check off its seat and lets the load move. Double pilot checks hold both sides of a cylinder.

For best results, pair them with a directional valve whose centre vents both work ports to tank. For heavy loads that must lower smoothly, a counterbalance valve is usually better.

Common Jobs

Stopping back flow through a pump when it stops
Isolating an accumulator so it holds its charge
Bypassing a filter or cooler if it becomes blocked
Holding loads on cylinders
Keeping water and process lines from draining back

Signs of a Failing Check Valve

A held load creeps down over time.
A pump spins backwards after shutdown.
The valve chatters or hammers during operation.
Pressure leaks back past the valve when the system stops.

Dirt on the seat is a common cause, so check the filters at the same time.

Check Valves Specifications to Check

Port size and thread, or cartridge cavity
Cracking pressure
Maximum pressure and flow
Standard or pilot operated, single or double
Medium: hydraulic oil, air or water
Body and seal materials

Why Buy From TSA Hydraulics Engineering

As a check valves supplier, we match the cracking pressure, size and mounting, so the valve protects the circuit the way the old one did. You get clear prices in AUD, OEM or equivalent options, and help sourcing check valves replacement parts such as cartridges, springs and seal kits. We tell you upfront whether a valve is genuine or an equivalent.

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