Introduction of Common Valves (3)

Besides gate valve, ball valve and globe valve and so on , plug valves, diaphragm valve and check valve are also very common valves. This paper mainly introduces the last three valves.

Introduction of Common Valves (3)

1.Plug valves

The plug valve is driven by the valve stem to make the plug body rotate, so as to achieve the purpose of opening and closing the pipelin with the advantages of good sealing, sensitive control, fast reaction speed, low working noise and so on.

2.Diaphragm valve

Diaphragm valve structure and working principle and other valves have obvious differences, is the use of rubber film and plastic film to achieve control function, the application of diaphragm valve in the pipeline medium must contain hard suspended matter, at the same time for pipeline pressure also has a certain limit.

3.Check valve

Introduction of Common Valves (3)

Check valve can keep single direction flow of pipeline medium, prevent backflow of medium, suitable for corrosive medium and pipeline with high pressure, also can be used in chemical sewage treatment system, with high economic value and practical value.

Above all, we know the several common valves. We are a factory manufacturing gate valve globe valve check valve, etc. If you want to know more about our valves or the knowledge of valves, click on the website:

There are many kinds of valves with different performance. The following is to introduce the difference between ball valves and check valves.

Ball Valves vs. Check Valves

Ball Valves

Ball valves can be defined as the opening and closing member (ball) driven by the stem, and rotational movement around the axis of the ball valve valve. They can also be used for fluid regulation and control. The hard-sealed V-ball valve has a strong shear force between the V-ball core and the metal seat of the welded carbide, especially suitable for media containing fibers, tiny solid particles, etc.. While the multi-way ball valves in the pipeline not only can flexibly control the media merging, diverging, and switching of flow direction, but also can close any channel and connect the other two channels. This type of valve in the pipeline should generally be installed horizontally. Ball valves is divided into: pneumatic ball valves, electric ball valves and manual ball valves according to the drive mode.

Ball Valves vs. Check Valves

Method of Pressure Test

The strength test of the pneumatic ball valves should be conducted in the half-open state.

1)  Floating Ball Valve Sealing Test

In a half-open state, one end of the valve introduced into test media, and the other end is closed; Turn the ball several times, then check the closed end of valve in the state of closing, as well as the packing and gasket sealing performance preventing from leakage. Then introduces the test medium from the other end, repeating the above test.

2) Trunnion Mounted Ball Valve Sealing Test

Rotate ball in the closing state several times before the test, introducing the test medium to the specified value from one end; use the pressure gauge (accuracy 0.5 ~ 1 level) to check the sealing performance of the introduction end, with the range of the test pressure 1.5 times. In the specified time, it is qualified without phenomenon of pressure drop; and then introduce the test medium from the other end, repeating the above test. Then, put the valve in a half-open state with both ends closed and the cavity filled with media, checking the packing and gasket at the test pressure without leakage.

3) Three-way ball valves should be tested in each position for tightness.

Check Valves

Check valves are automatically opened and closed by the force which is generated by the flow of the medium in the pipeline. Check valves used for pipeline system prevent the backflow of media, the pump and drive motor reversal, as well as the release of container media. They can also be used to provide recharge to the auxiliary system in which the pressure may rise above the system pressure, which mainly can be divided into rotary (rotating according to the center of gravity) and lift (moving along the axis).

Ball Valves vs. Check Valves

Working Principle

The opening and closing part as circular valve disc relies on its own weight and medium pressure to produce action to block the backflow of the medium.

Scope of Application

Fire pump discharge pipe, high level fire water tank discharge pipe, pressure stabilization pump discharge pipe, pump splicer and other locations.

Supplementary note: It includes the anechoic check valve and water hammer elimination check valve. Measures are set up inside the valve body to reduce the sound of the valve flap impact when the valve is closed and eliminate water hammer.

Check Valve Pressure Test Method

Check Valve Test State

The disc axis of lift check valve is vertical, while swing check valve channel axis and disc axis in a position approximately parallel to the horizontal line.

When strength test, the introduction of test media from the inlet end to the specified value, the other end closed, make sure the valve body and valve cover no leakage for qualified.

Introduce test media from the outlet side at the inlet end to check the sealing surface, packing and gasket at no leakage for qualified.

1. Production Introduction

Non-slam check valve is a new concept series. This product is  designed according to the basic principle of differential flow adjustable valve. The internal flow channel of the Non-slam check valve adopts a streamline design and is provided with a guiding fluid. It is mainly used at the pump outlet or other places to prevent the backflow of liquid. It can prevent the water hammer impact and noise caused by the backflow of the ordinary check valve. It is silently closed and has good sealing performance. It is a product of the replacement of the check valve.

2. Main Characteristics

a.  Adopt double sealing structure. Regardless of the pressure behind the valve, the valve is closed tightly and has good sealing performance, which overcomes the disadvantage of poor sealing performance of general check valves under medium and low pressure conditions.

b.  At low flow rates, the valve can be fully opened, and different impedances can be selected to meet the requirements of different situation. Under normal circumstances, the valve opens and closes quickly. If the user needs, it can also be designed as a check valve with a slow-closing structure to meet the needs of its device.

c. The streamlined flow channel and the diversion structure are adopted, and the valve flow resistance is small.

d. The springs are designed as Class I springs and are normally made of stainless steel.

3. Installation Illusion

a. The valve is not limited by the installation position and can be installed horizontally or vertically.

b. Before installation, thoroughly remove the garbage and sundries in the pipeline to prevent the garbage from jamming the valve seat and valve disc during use, resulting in non-stop return or damage to the valve seat and valve disc. Please install a filter before the valve.

c. When installing, pay attention to the arrow indicating the water flow outside the valve, and follow the installation direction.

d. When the valve is not used for a long time, or when the water does not flow, please pay attention to preventing freezing and drain the water in the valve.

4. The Main Technical Data

Nominal pressure PN(MPa) 1.0  1.6 2.5 4.0  6.4  10.0
Shell test(MPa) 1.5 2.4 3.75 6.0  9.6 15.0
Working temperature 0~200℃
Media Water, oil, etc

5. Simple Diagram

ZJCLV Non-Slam Check Valve Manual

1— Body;

2— Seat;

3— Disc;

4— Spring;

5— Guide Sleeve;

6— Guide Cover.

ZJCLV Non-Slam Check Valve Manual
ZJCLV Non-Slam Check Valve Manual