Check valves
What Is a Check Valve?
Specifiation of Hydraulic Check Valve
| BRAND NAME | TU-LOK |
| INSTRUMENTATION VALVES SIZE | 1/8″ TO 2″ / 6 MM TO 50 MM |
| CONNECTION | THREADED, TUBE END, SOCKET WELD END, FLANGE END |
| THREADS | NPT, BSPP, BSPT, METRIC, JIC, UNF |
| FLOW PATTERN | STRAIGHT |
| INSTRUMENTATION VALVES BODY SHAPE | HEXAGON |
| PRESSURE RATING | 1500 PSI, 3000 PSI, 6000 PSI, 10000 PSI, 15,000 PSI, 20000 PSI |
| CRACKING PRESSURE | 0.5 BAR |
| INSTRUMENTATION VALVES ORIFICE SIZE | 2 MM TO 40 MM |
| TYPE | POPPET TYPE, SPRING TYPE |
| MEDIA | HYDRAULIC OIL, AIR, WATER, GAS, STEAM, HOT WATER, COLD WATER, SEA WATER, CHEMICAL |
| MEDIA TEMPERATURE | (-50°C TO 350°C) RANGE AS PER PRESSURE |
| BODY TYPE | BAR STOCK, FORGED |
| INSTRUMENTATION VALVES PACKING DETAILS | BOX PACKING, WOODEN PALLET |
| EQUIVALENT BRANDS | SWAGELOK, PARKER, STAUFF, DK-LOK, HAMLET, OLIVER VALVES, HOKE |
| INSTRUMENTATION VALVES MATERIAL | SS 304, SS 316, SS 316 TI, BRASS, COPPER, CS, DUPLEX, SUPER DUPLEX, INCONEL, MONEL, HASTELLOY, SMO 254, ALLOY 20, TITANIUM, 904L & ALL OTHER ALLOYS |
Different Types of Check Valve
- Spring-Loaded Check Valves – Compact design, closes automatically when flow stops.
- Poppet Check Valves – Reliable sealing with minimal leakage, suitable for high-pressure systems.
- Ball Type Check Valves – Simple design with a spherical ball as the closing element, excellent for fluids and gases.
- Shuttle Valves – Allow flow from two inlets to one outlet, common in hydraulic circuits.
- Pilot Operated Check Valves – Use an external pilot signal to control reverse flow, often used in hydraulic systems.
- Wafer Check Valves – Lightweight, thin profile, and easy to install between flanges.
- Swing Check Valves – Use a swinging disc to block reverse flow; ideal for low-pressure, large pipelines.
- Stop Check Valves – Combine check and stop functions, allowing manual closure as needed.
- Lift Check Valves – The disc lifts vertically when forward flow occurs; works well with high-pressure service.
- Diaphragm Check Valves – Flexible diaphragm ensures tight sealing; suitable for corrosive or abrasive media.
How Does a Check Valve Work?
A check valve is designed to let fluid flow in only one direction while preventing backflow that could damage pumps, pipes, or equipment. Its operation depends on two main principles: cracking pressure and closing mechanism.
Cracking Pressure
To start flowing, a check valve needs a certain minimum pressure difference between the inlet and the outlet. This is called the cracking pressure.
- Most check valves have a cracking pressure of 1 bar (14.5 psi) or lower, which means they open easily for general fluid systems.
- In specialized systems, such as hydraulic check valves, a higher cracking pressure may be required to ensure proper performance before the valve opens.
This ensures that media like water, oil, gas, or chemicals pass through the valve only when the system pressure reaches the required level.
Closing of the Valve
When the system pressure drops below the cracking pressure, or if fluid tries to flow backward, the check valve closes automatically.
- The closing element may be a gate, ball, diaphragm, or disc that presses tightly against the valve seat to stop flow.
- In many designs, gravity or a spring mechanism helps the valve close quickly and securely, preventing reverse flow and protecting the system.
This automatic open-and-close action makes check valves essential for oil & gas pipelines, water supply systems, HVAC units, and hydraulic applications in Qatar.
Choosing the right cracking pressure and valve type is critical for efficiency and safety. That’s why ABC Master Qatar offers expert guidance when selecting the right check valve for your application.
Why Choose ABC Master Qatar for Check Valves?
- Local support & inventory: Stocked here in Qatar for quick delivery and on-site support.
- Certified quality: All valves conform to international standards and are pressure-tested for reliability.
- Wide material options: We can supply from general purpose stainless steel to specialty alloys for corrosive or extreme environments.
- Expert guidance: Our team helps you select the right check valve type, size, and rating to match your system’s pressure, temperature, and fluid needs—optimizing safety and performance.