Compared with other valve driving devices, electric driving devices have the characteristics of wide power source, fast and convenient operation, and can easily meet various control requirements. Therefore, among valve driving devices, electric devices dominate. ◆Valve electric devices are divided into two types according to the input mode: multi-turn type (Z type) and partial rotation type (Q type). The former is used for lift rod valves, including: gate valves, globe valves, throttle valves, diaphragm valves, etc.; The latter is used for rotary rod valves, including ball valves, plug valves, butterfly valves, etc., which usually open and close within the 900…
Earlier, the control signal of industrial control instruments was 0~10mA, that is, "0" corresponds to the "fully closed" state of the instrument, and "10" corresponds to the "fully open" state of the instrument. With the development of computers, modern instruments are increasingly controlled by computers and DCS systems, which also brings problems; there are two states that cannot be distinguished (both signals are "0" states) 1) Industrial control instruments The control signal is "0" 2) When the computer fails, the break signal will generate a "0" signal. In order to distinguish the two states and prevent misoperation, the 0~10mA signal…
1. The function of gate valve: The opening and closing part of the gate valve is the gate plate. The movement direction of the gate plate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and is not suitable for adjustment and throttling. The gate has two sealing surfaces. The two sealing surfaces of the most commonly used wedge gate valve form a wedge shape. The wedge angle varies with the valve parameters, usually 5o. The gate plate of the wedge gate valve can be made into a whole, called…
Currently, many developed countries in the world have formulated pressure and temperature rating standards for valves, pipe fittings, and flanges. Today we focus on China, the United States, Germany and international standards: 1. Chinese National Standards The national standard GB/T 9124-2000 "Technical Conditions for Steel Pipe Flanges" refers to the principles and methods for formulating pressure and temperature ratings in the German DIN 2401-1977 and the American ASME/ANSI B16.5a-1992 standards, and uses the commonly used standards in my country Flange materials refer to the international standard ISO/DIS7005-1-1992, and flange pressure-temperature ratings suitable for two nominal pressure series (PN0.25~4.0MPa, PN2.0~42.0MPa) are…
1. Dimensional parameters In order to meet the industrial requirements of high temperature, low temperature, strong corrosion, strong erosion and long life, metal-sealed butterfly valves have become one of the fastest growing valve varieties in recent years. In some special occasions, higher requirements are placed on the sealing of metal hard-seal butterfly valves, which must bear pressure in both directions. At present, metal hard-seal butterfly valves on the domestic and foreign markets mostly adopt double eccentric and three-dimensional eccentric sealing principles. Both sealing structures have better sealing effects when the medium is in the forward flow state; when the medium…
Three-way valves are widely used in the chemical, plastic, and foundry industries. In the past, most of them were manually operated. With the development of science and technology, automatic control technology has been widely used in various production fields. It was under this circumstance that the air-controlled three-way valve was born. The pneumatic three-way valve can realize automatic control during the production process through electric-pneumatic control technology. Pneumatic three-way valve structure diagram (1. Cylinder block 2. Piston 3. Piston rod 4. Cylinder head 5. Roller assembly 6. Spiral guide sleeve 7. Protective cover 8. Valve stem 9. Adjustment wire sleeve…
The foot valve is an energy-saving valve and a type of check valve. Generally installed at the bottom of the underwater suction pipe of the water pump. It restricts the return of liquid in the water pump tube to the water source, and has the function of only entering but not exiting. There are many water inlets and reinforcing ribs on the valve cover to prevent clogging. It is mainly used in water pumping pipelines. The role of water channels and supports. The calibers include single-valve, double-valve, and multi-valve types. There are flange connections and threaded connections. Other names: Internal…
The safety valves produced by Hebei Zhenchen Machinery Equipment Group Co., Ltd. are widely used as overpressure relief devices on boiler pressure vessels. Whether their performance can meet the requirements is crucial to the safe operation of boiler pressure vessels. According to relevant regulations, safety valves should be inspected regularly, at least once a year. Article 145 of the "Steam Boiler Safety Technical Supervision Regulations" stipulates that for safety valves of newly installed boilers and safety valves after maintenance, their opening pressure (set pressure) and sealing pressure must also be inspected. Our country stipulates that the sealing test pressure of…
Hydraulic device is a driving device that uses hydraulic force to open, close or adjust valves. It consists of three parts: control, power and actuator. The control part consists of pressure control valve, flow control valve, directional control valve, etc. and electrical control system. The power part is composed of an electric motor or a pneumatic motor, a hydraulic pump, a fuel tank and other parts. It converts the effective power on the rotating shaft of the electric or pneumatic motor into fluid pressure energy for hydraulic transmission. There are two types of actuators, one is a hydraulic cylinder actuator,…
Valve installation requirements Hebei Zhenchen believes that the quality of valve installation will directly affect the future use of the valve. Therefore, construction units and production units should pay great attention to it. The installation of the valve should be carried out in accordance with the valve instruction manual and relevant regulations. During the construction process, careful inspection and careful construction are required. Before installing the valve, the pressure test should be passed before installation. Carefully check whether the specifications and models of the valve are consistent with the drawings, check whether all parts of the valve are intact, whether…
Shanghai Fanggong believes that the pump valve is one of the key components and wearing parts of the drilling pump, and its design directly affects the working performance and service life of the pump. On the one hand, to improve the erosion resistance of the pump valve contact surface, it is necessary to increase the surface hardness of the contact surface, and excessive hardness will weaken the impact resistance. On the other hand, in order to improve the material's ability to withstand impact loads, it is necessary to ensure that the material has high toughness, and the corresponding hardness will…
1 Overview The high-pressure hydrogenation process is an important means of deep processing of petroleum. It can not only improve the recovery rate of light oil per unit of crude oil. And it can improve the quality of fuel oil, thereby improving the overall efficiency of the refinery. The high-pressure hydrogenation device can also provide high-quality raw materials for petrochemical devices and is also an ideal device for oil desulfurization. China began the construction of high-pressure hydrogenation units in the 1990s. It is expected that in the next few years, as the amount of foreign oil refining in our country…
