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.

In this article, we will list out several points regarding the installation of spring relief valve.   First, before installation, we need to check the sealing performance of the spring relief valve. The valve has to be fixed if seat leaking or broken air cushion is found.   In addition, we need to pay special attention to the vertical installation of valve. The installation angle should be precise and formal. And make sure all the necessary installation tools are ready.   Second, it is not allowable to apply pressure on the exit of the relief valve during the installation of relief valve. We had better making it empty directly so that the relief valve can work effectively.   Third, the operator should wear gloves during installation to prevent the oil on the hand from polluting the valve. The oil pollution can influence the sealing performance of relief valve. Meanwhile, it will also reduce the overall service life of relief valve.   Last but not least, two operators are needed on the spot of valve installation to make sure the normal function of the valve.

As the most prestigious exhibition in the valve industry, Valve World Expo in Germany attract thousands of valve companies and people involved in valve industry around the world to seek business opportunities her every year. This year, Dervos also have a booth here. The team took off from Beijing Airport to Dusseldorf on Nov 30th, fully prepared for the coming fair. During the exhibition, many clients came to our booth for discussion of future cooperation, and a lot of potential clients were attracted here by our excellent samples and professional presentation. Dervos has achieved a great success here in Valve World, and we aim to attend the next one in 2016!