A Brief Introduction to Check Valves

The closure parts of the shut-off valve are plug-shaped valve discs, with sealing surfaces that are either flat or conical. The valve discs move in a straight line along the centerline of the fluid. The motion of the valve rod can be either lifting rod style (the rod rises and falls, while the handwheel does not), or lifting and rotating rod style (the handwheel rotates and rises or falls with the rod, with the nut mounted on the valve body).

Check ValveIn the case of a forced-sealed valve, pressure must be applied to the valve disc when the valve is closed to ensure the sealing surface does not leak. As the medium enters the valve six from below the valve disc, the resistance that must be overcome by the operating force is the friction between the valve stem and the packing, as well as the thrust produced by the pressure of the medium. The force required to close the valve is greater than that to open it, hence the diameter of the valve stem must be larger to prevent the stem from bending. In recent years, since the emergence of self-sealing valves, the medium flow direction of the stop valve has changed to entering the valve cavity from above the valve disc. Under the action of the medium pressure, the force required to close the valve is reduced, while the force to open it is increased, allowing the diameter of the valve stem to be reduced accordingly. Additionally, under the action of the medium, this type of valve is also more airtight. China's valves...“Sanhua Gives”It was previously stipulated that the flow direction of check valves should always be from top to bottom.

Valves are categorized by the position of the valve stem thread into external threaded and internal threaded types. According to the flow direction of the medium, they are divided into straight-through, direct-acting, and angle types. In terms of sealing form, there are stuffing box sealed check valves and bellows sealed check valves.

Installation and Maintenance of Shut-off Valves

Wedge gate valves operated by handwheels and handles can be installed at any location on the pipeline.

Handwheels, handles, and drive mechanisms are not permitted for lifting purposes.

The flow of the medium should be consistent with the arrow direction indicated on the valve body.

At the opening of the stop valve, the lift height of the valve disc is equal to the nominal diameter.25%～30%At this point, the flow has reached a high volume, indicating that the valve has reached its fully open position. Therefore, the fully open position of the shut-off valve should be determined by the stroke of the valve disc.

The shut-off valve boasts the following advantages:

1Simple structure, easy to manufacture and maintain.

2The work schedule is compact, with short opening and closing times.

3Excellent sealing performance, low friction between sealing surfaces, and longer lifespan.

Disadvantages of shut-off valves include:

1High fluid resistance, requiring significant force for opening and closing.

2Not suitable for media with granules, high viscosity, and prone to coking.

3Performance adjustment is poor.

The types of stop valves are categorized by the position of the valve stem thread, including external threaded and internal threaded styles. According to the flow direction of the medium, there are straight-through, direct-acting, and angle types. In terms of sealing form, stop valves are divided into packing-sealed and bellows-sealed types.

Valve Installation and Precautions:

1Cut-off valves operated by handwheels and handles can be installed at any position on the pipeline.

2Wheels, handles, and power transmission devices are not permitted for lifting purposes.

3The flow of the medium should be consistent with the arrow direction indicated on the valve body.

特点 of Cut-off Valve Structure:

1. The valve's interior cavity employs a pressure self-tightening sealing structure, offering superior sealing performance..

2. The sealing surfaces of the valve disc and seat are sintered with Stellite cobalt-based hard alloy.,Abrasion-resistant, heat-resistant, corrosion-resistant, scratch-resistant, and durable..

3. High-Temperature Creep-Resistant Design.

4. The valve rod is crafted with a solid forging structure.,Heat treated and surface nitrided,Excellent corrosion and abrasion resistance..

5. Valve cover stuffing box depth is reasonable.,Filler with Antirust Agent,Sealed and Reliable.

Pipe cutting or connecting media on pipelines for high-temperature and high-pressure water, metallurgy, steam, oil products, and superheated steam, suitable for power plants, petrochemicals, and metallurgy industries.