1. Price Whether they are domestic pneumatic valves and electric valves or imported pneumatic and electric ones, their prices are essentially the same. However, because pneumatic valves need to be equipped with air source facilities (e.g. the air compressor station), the electric valve has an advantage in price. 2. Reliability of valves It is believed that pneumatic valves have extremely high reliability while the reliability of...

The ductile iron is ideal for valve materials, for it has lots of merits. As a substitute for steel, ductile iron was developed in 1949. The carbon content of cast steel is less than 0.3%, while that of cast iron and ductile iron is at least 3%. The low carbon content of cast steel makes the carbon existing as free graphite not form flakes. The natural form of carbon in cast iron is free graphite flakes. In ductile iron, graphite is in the form of nodules rather than flakes as in cast iron....

1. For natural gas ball valve, conductive springs are set between the ball and the stem, and between the stem and the valve body to form electrostatic channels, thus achieving the purpose of removing static electricity and avoiding igniting flammable medium by electrostatic ignition to ensure system security. In case of fire, the soft seal ring such as PTFE O-rings being burned, the ball valve can still operate reliably and has good sealing to prevent the spread of...

When defects appear on the sealing surfaces of valve heads and valve seats, if the defect depth is less than 0.5mm for valves without being nitrided, abrasive machining shall be done directly to eliminate the defects or the method of lathe machining before abrasive machining shall be adopted, which depends on the damage condition of the sealing surfaces. If the surface of the valve is nitrided, the valve should be nitrided again after eliminating the defects on the sealing...

The Y strainer is a common strainer on the pipeline transporting media. It is usually installed at the inlet end of pressure reducing valves, pressure relief valves, level control valves or other equipment of the water supply. And it is used to remove impurities in the medium and protect the valve from seal failures caused by mechanical impurities stuck in the seal ring, thus ensuring the normal operation of the valve and other equipment. The application scope of Y strainers...

Structural features of electric PVC ball valves The electric PVC ball valve, belonging to the quick opening & closing valve, has a simple structure, a small size, light weight, small driving torque, etc. It is used to cut off or adjust the medium in the pipeline, and has good sealing performance. The valve seat has good sealing. And the seal capacity of the ball valve increases with the increase of the working pressure of the ambient medium. The thrust bearing reduces...

A Threaded Connection It is a simple connection method, which is often used for small valves. The inlet and outlet of the valve are usually machined into taper pipe threads or straight pipe threads. The joint may leak if the threaded connection is used, and sealant, sealing tape or filler can be used to fill it. Threaded valves are mainly valves with a nominal diameter below 50 mm. If the diameter is too large, it is very difficult to install the valve and...

Stainless steel check valves are used to make valves unblocked or blocked by rotating valve stems. It can be made of large diameter ball valves with 90 angle. As the switch of ball valves is light in small volume. So, it can be made ones with large diameter, reliable sealing, simple structure and convenient maintenance. The sealing surface and spherical surface are usually closed, and it is not easy to be eroded by medium. Stainless steel check valves are divided into low pressure stainless steel...

1.Overview Butterfly type microresistance slow closing check valve (WZHF) is mainly used in water conservancy, electric power, water supply and drainage, municipal engineering, petroleum, petrochemical, metallurgy and other industries. It can effectively eliminate the water hammer in the pipeline and realize the reliable check of the pipeline so as to protect the pipeline system. 2.How it works? When the water pump is started, the check valve will open automatically under the action of water pressure,...

In the daily use of valves, various failures often occur. The leakage of valves is the most common one among many failures and it generally includes internal leakage and external leakage. So, what is the difference between the two? The internal leakage of the valve usually refers to the condition that the medium still leaks from the passageway of the valve when the valve is completely closed. Generally speaking, the internal leakage means that the valve is not...

The unusual pressure rise of cast steel gate valves happens strikingly and similarly in many relative applications, because the two major factors of its occurrence are similar in lots of industrial systems, that is, the system medium changes from cold state to thermal state after starting up. The gate is closed in cold state and opened in thermal state. Therefore, if no measures are taken for the system, the damage to the system caused by the unusual pressure rise is...

According to the requirement for engineering controls, the control function of electric butterfly valves is achieved by the electric actuator. The purpose of using electric butterfly valves is to control the opening, closing and regulating linkage of the valve by non-manual electrical control or computer control. At present, the use of the electric actuator is not only to save manpower. Because the function and quality of products from different manufacturers are...