Non return valve - spring check - brass c/w nylon valve

Brass Spring Check Non-Return Valve, stops pumped water draining back down the hose

A compact, one-piece brass non-return valve that fits inline between your pump outlet and your discharge hose. Water passes freely on the way out; the moment flow stops or tries to reverse, a spring pushes the nylon plate onto its seat and closes the line. Available in nine sizes from 12mm to 100mm, with BSP female threads at both ends.

What does a non-return valve actually do on a pump?

When a pump stops, the water sitting in the discharge hose has nowhere to go but back the way it came. On a short, level run that is a nuisance. On a long run, or where water is being lifted over a height, it is a real problem: the returning column drains back through the pump and into the space you have just cleared, and the pump has to re-prime and move the same water twice.

A non-return valve holds that column in the hose. You keep the ground you have gained, the pump restarts against a primed line rather than an empty one, and on automatic installations the pump stops short-cycling on water it has already moved.

Why spring check rather than swing check?

A swing check valve uses a hinged flap and gravity, so it needs to be installed the right way up to seal properly. A spring check uses a spring to push the plate closed, which means it will seal regardless of how it is mounted, vertical, horizontal or at an angle. That makes it the more forgiving choice for temporary set-ups, hire fleets and awkward pump chambers where you cannot always control the pipe run.

The trade-off is that a spring check needs a little pressure to push it open, so it introduces slightly more resistance than a swing check of the same size. On a pump discharge this is rarely significant, but if you are working at the very top of a pump's head curve it is worth considering our brass swing check valve instead.

What is it used for?

• Submersible drainage and site dewatering pumps
• Sump pumps and packaged pump stations
• Puddle pumps and low-level pumping, where air draw at the end of a pump-down is normal
• Long discharge runs and lifts over height
• Booster sets and pressure systems
• Rainwater harvesting and greywater transfer
• Protecting a pump from reverse rotation when a second pump on a shared rising main runs

Construction

• Brass body: one-piece, machined, with a hex section for a spanner
• Nylon plate: light, corrosion-free and quiet in operation
• Stainless steel spring: will not rust in standing water the way a plated steel spring does
• BSP female threads both ends: screws straight onto a threaded pump outlet, with a hose tail into the other side

Brass suits most clean and lightly contaminated water duties and handles the knocks of site work far better than a plastic body. Where the fluid is aggressive, or weight and cost matter more than robustness, our polypropylene spring check valve is the alternative.