Design and principle of operation of the reverse coupling gate

Check clutch valves, also known as check valves or one-way valves, are designed for one-way fluid supply to the pipeline. The device is connected to the pipeline by means of a transitional threaded coupling. The presence of such a gate prevents the unpleasant phenomenon of hydraulic shock, which can cause a pipe rupture.

Device and control features

The typical design of a reverse type hydraulic lock with threaded mounting includes:

• A cap suspended on a hinge, which is located at the bottom of the product.
• The hinge itself (pusher or thrust).
• The valve body, which is made of brass, bronze or stainless steel.
• Threaded coupling (optional).

The basic design of the check valve prevents the backflow of liquid in the pipeline. The control part of such devices is missing. Therefore, reverse coupling valves, as a rule, operate without automation or human intervention, and instead act depending on the fluid flow rate when opening and closing. The minimum inlet pressure required for the valve to operate is the main factor affecting the valve design.

Depending on the overall dimensions and material, standard versions of coupling hydraulic locks are calculated for flow pressure in the range from 7 to 35 kPa.

The degree of opening of the check valve is determined by the flow rate. The higher the flow rate, the more the valve will be open until it completely moves to the open position. In most designs it is about 850.

Types of Reverse coupling valves

There are many types of devices under consideration, including:

• Check valves with a check or rotary disc. They consist of a cap with a disk, which is convex on the input side, and flat on the output side (downstream). The disc, in turn, swings on a hinge or trunnion attached to the bottom of the valve cover. For some designs of such disc valves, a cast pocket is provided in the housing with a stop in the shaft/pin and sleeve;
• Check valves with a finger that is located in the inner protrusions of the housing. This option is more modern, because it improves the conditions for holding the cap in case of sudden changes in flow;
• Ball-type return coupling valves. They have a spherical cap, which is sometimes spring-loaded to ensure sealing at pressures below the cracking pressure. Such valves can easily wear out during prolonged use and require frequent maintenance; therefore, they should be installed in places easily accessible to repair crews;
• Membrane hydraulic valves equipped with a rubber membrane flap. When opened, it bends when the pressure on the inlet side exceeds the pressure on the outlet side, and closes when this pressure equalizes or falls below the set level.

Check clutch valves have an additional external control mechanism (for example, drive, lever/flywheel, etc.), which allows the valve to be closed regardless of the actual value of the flow pressure.