The main differences between electric butterfly valve and electric gate valve lie in structure, operation time, size, price, sealing performance and so on. In this article, we will discuss these differences in detail. 1. Compared to gate valve, electric butterfly valve owns simpler structure, smaller volume, lighter weight, so smaller installation space. 2. Butterfly valve’s operation time is shorter and its flow resistance coefficient smaller. 3. Electric gate valves can handle higher pressure and create a better sealing performance than electric butterfly valves. 4. Electric gate valves are only suitable to cut off the flow, but electric butterfly valves can adjust the flow and cut off flow at the same time. 5. Unlike electric butterfly valves, electric gate valves can work in higher temperature and pressure conditions because of its wear ability. 6. Overall, electric gate valves are more expensive than butterfly valve. 

The pneumatic cut-off ball valve is equipped with a stroke limit switch, a solenoid valve, a pressure reducing valve and a 0.4-0.7 Mpa air source, which can realize the switching operation and send out two passive contact signals indicating the valve switch. Actuators can be divided into two types: single-acting actuators and double-acting actuators. The unique advantage of single-acting actuators is that in the event of a power failure, the pneumatic shut-off ball valve will automatically open or close according to system requirements. Pneumatic cut-off valve is widely used in chemical, petroleum, textile, electric power, food and pharmaceutical, refrigeration, aviation, aerospace, papermaking and other industries. It can not only control gas, liquid and vapor media, but also can be applied to sewage control. Characteristics of pneumatic cut-off ball valve 1. The fluid resistance is small, the ball valve is one of the valves with the smallest fluid resistance. Even if the ball valve is reduced, its fluid resistance is very small. 2. Thrust bearing can reduce the friction torque of the valve stem and make the valve stem smooth and flexible. 3. Good valve seat sealing performance. Sealing rings are made of Teflon and other elastic materials for excellent sealing work. In addition, with continued high and medium pressure, the sealing capacity of the ball valve will increase. 4. Reliable valve stem sealing performance. Because the valve stem itself can only perform rotary motion instead of lifting movement, the packing seal of the valve stem is not easy to be damaged, and its sealing performance will be better as the medium pressure increases. 5. Due to the good self-lubricating performance and small friction loss of Teflon and other materials, the pneumatic cut-off ball valve can have a longer service life.

Generally speaking, we have five main principles for valve electric actuator selection.   1. Operation torque is one of the most critical parameters in selecting actuator. We should bear in mind that the electric actuator’s output torque should be 1.2~1.5 times larger than the maximum valve operation torque.   2. We should control the opening and closing speed of valve by regulating the output speed of actuator in a proper range, otherwise it will appear water hammer easily.   3. There are two kinds of master structures to operate the trust of electric actuator: one is not configured with trust plate but outputting the torque directly, while the other one is outputting the switched torque by stem nut.   4. The rotation numbers of output shaft is related to nominal diameter, stem pitch and number of starts. And the formula is M=H/ZS. (M is the total number of rotation number, H is the operation height of the valve, S is the stem pitch and Z is the number of starts)   5. Valve electric actuator has its own special requirements and it must be able to limit the torque and axial force. Normally, electric actuator is equipped with coupling to limit the torque. After the standard of an electric actuator is determined, the torque is also determined.

In this article, we will introduce the advantage, disadvantage and installation tips of globe valve. Globe valve has the following merits: 1. Easy to manufacture and be maintained due to its simple structure.                   2. Short opening and closing time with small working stroke. 3. The globe valve owns a good sealing performance. 4. The small frictional force between sealing surface leads to longer service life of globe valve. Globe valve has the following disadvantage: 1. The fluid resistance of globe valve is big, which requires larger force during operation. 2. Globe valve is not suitable coking medium with larger particles and viscosity. 3. Globe valve has poor regulation performance. Types of globe valve: 1. According to the position of the valve stem thread, we have external thread type globe valve and internal thread type globe valve. 2. According to the flow direction of medium, we have straight-through globe valve, straight-flow globe valve and angle type globe valve. 3. In terms of the sealing form, globe valve has packing seal globe valve and bellows seal globe valve. The following aspects should be paid attention to when globe valve is installed and maintained. 1. Globe valve with manual operation can be installed in any position. 2. The hand wheel and handle do not allow for lifting. 3. The flow direction of medium should be consistent with the direction arrow on the valve body.

For electric butterfly valve, there are mainly two types. One is on-off switch type and the other intelligent type. The working principle is that: match butterfly valve with the DSR actuators, input control signals and single-phase-power supply, so that the electric butterfly valve’s operation can be controlled.   The electric butterfly valve owns a very good performance by having small volume but large flow capacity, reliable sealing performance and simple matching. The electric butterfly valves are widely used in light industry, petroleum, water treatment, paper manufacturing, chemical, electric power and many other industrial automatic control systems.

We often have soft seated for iron gate valve. Many people would like to know how to operate soft seated gate valve. Here are four tips. First, always remember that we should close soft seated gate valve in clockwise direction. Second, when soft seated gate valve used in pipeline, we should apply manual operation to the pneumatic device inside the valve. The frequency of valve operation cannot be too often in case of the damage to the soft seal. For large size valve, the times of opening and closing should remain between 200~600 times. Third, the opening and closing force spacing should be limited in a certain range. This is mainly to save manpower, and convenient to be operated by one person. If the force spacing is over this range, we need at least two or three people to operate the valve. Fourth, the size of the valve must be according to standard. It is important to face the seal valve gate valve down when putting valves in place.