In short: a check valve that closes late slams shut against reverse flow and sends a pressure wave down the line. Non-slam designs close before the flow reverses. BTGC supplies KSB check valves, butterfly valves and gate valves for water transmission and power plant cooling water.
Saudi Arabia pumps potable water from coastal desalination plants to cities hundreds of kilometres inland, through some of the longest water transmission lines in the world. Every pumping station on those lines has check valves, and a check valve that slams is one of the most common causes of damage to pumps, pipes and supports.
Why check valves slam
When a pump stops, the water in the line decelerates and then starts to flow back. A conventional swing check valve closes only when reverse flow pushes the disc shut. By then the water is already moving backwards; the disc hits the seat and stops the column instantly. The result is a pressure spike, the bang that operators call slam, and over time cracked bodies, broken hinge pins and loosened pipe supports.
How a non-slam valve works
A non-slam check valve closes while the forward flow is still decelerating, before any reverse flow develops. Three design elements make this possible:
| Element | Effect |
|---|---|
| Short disc travel | The disc has less distance to move, so it closes faster |
| Spring assistance | The spring starts closing the disc as soon as forward flow weakens |
| Low disc mass | Less inertia, so the disc follows the flow instead of lagging it |
Nozzle check valves and spring-loaded dual-plate designs are the common non-slam types. For very long lines, the check valve is part of a surge protection scheme with surge vessels and controlled-closing butterfly valves.
KSB valves from BTGC
KSB of Germany is one of the world's largest manufacturers of pumps and valves and a leading supplier to the water and power sectors. The range BTGC supplies in the Kingdom covers:
Non-slam check valves for large pumping stations
Centric, double-offset and triple-offset butterfly valves for water, gas and process
Gate and globe valves to DIN and ANSI standards for power plants and general industry
Applications in the BTGC catalogue are SWCC water transmission lines, power plant cooling water and general industry. See our page for KSB valves in Saudi Arabia and the full industrial valves offer.
Local content
Alongside KSB, BTGC supplies locally made water valves from AVK's Saudi facility and locally assembled Crane valves, so a water project can meet local content targets within one package. Ask BTGC to split the valve list between imported and locally made items.
BTGC support in Dammam, Jubail and Yanbu
BTGC supports water and power utilities from the Gulf and Red Sea coasts, with valve testing and repair at the service center in Jubail. For a quotation send the line size, pressure class, flow and the pump trip scenario; BTGC can arrange a surge study for the station.
Questions buyers ask
Is a dual-plate check valve non-slam? Spring-loaded dual-plate valves close quickly and are used as non-slam valves on many lines; for the largest pumps a nozzle check valve is the safer choice.
Can slam be fixed without replacing the valve? Sometimes with a damper or a spring upgrade; usually the lasting fix is a non-slam design.
Does BTGC supply the surge vessels too? Yes, surge vessels and controlled-closing butterfly valves are part of the water package.
Contact the BTGC valve team
Email valves@btc-ksa.com or call +966 13 856 0528. Branches: Dammam, Jubail and Yanbu. Request a quote.