The operation of a fan coil unit requires not only the fan coil unit itself, but also the support of other fan coil unit parts, so that the fan coil unit can run well. The ten common components in fan coil unit are: four-way valve, solenoid valve, thermal expansion valve, gate valve, butterfly valve, etc., which are all important components for controlling the medium in fan coil.
1. solenoid valve
Solenoid valve is an industrial equipment controlled by electromagnetism, which is an automatic basic component for controlling fluid. It belongs to actuators and is not limited to hydraulics and pneumatics. Used in industrial control system to adjust the direction, flow rate, speed and other parameters of medium. The electromagnetic valve can be matched with different circuits to realize the expected control, and the control precision and flexibility can be guaranteed. There are many kinds of solenoid valves. Different solenoid valves play a role in different positions of the control system. The most commonly used ones are one-way valves, safety valves, directional control valves, speed control valves, etc.
2. Thermal expansion valve
The thermal expansion valve controls the refrigerant flow into the evaporator by controlling the superheat of gaseous refrigerant at the outlet of the evaporator. The thermal expansion valve realizes throttling from condensation pressure to evaporation pressure and controls the flow of refrigerant at the same time. Although its volume is small, it plays a great role. Its working quality directly determines the working quality of the whole system. It supplies liquid to the evaporator in the best way to ensure the stability of the superheat of refrigerant vapor at the outlet of the evaporator. The temperature sensing bag must be in good contact with the suction pipe of the compressor to sense the suction temperature of the compressor.
3. Four-way valve
Four-way valve, hydraulic valve term, is a control valve with four oil ports. The four-way valve is an indispensable component in refrigeration equipment. Its working principle is that when the solenoid valve coil is in power-off state, the pilot slide valve moves to the left under the drive of the right compression spring, and high-pressure gas enters the capillary tube and then enters the right piston cavity. On the other hand, the gas in the left piston cavity is exhausted. Because of the pressure difference between the two ends of the piston, the piston and the main slide valve move to the left, so that the exhaust pipe communicates with the outdoor unit connecting pipe and the other two connecting pipes communicate with each other, forming a refrigeration cycle.
4. Gate valve
A valve whose gate acts as an opening and closing member and moves vertically along the axis of the valve seat to realize the opening and closing action. The gate valve can only be fully opened and fully closed. The opening and closing parts are rams, and the moving direction is perpendicular to the fluid direction. The wedge shape formed by the two sealing surfaces of the square I-shaped gate valve varies with the valve parameters, usually 5, and when the medium temperature is not high, it is 2 52′. Improve the manufacturability of gate valves and make up for the deviation of sealing surface angle during machining. This kind of gate is called elastic gate.
5. Butterfly valve
Butterfly valve is a kind of valve whose closing part (disc or butterfly plate) is a disc, which rotates around the valve shaft to open and close, and it mainly plays the role of cutting off and throttling on the pipeline. The opening and closing part of butterfly valve is a disc-shaped butterfly plate, which rotates around its own axis in the valve body, so as to achieve the purpose of opening and closing or adjusting. Butterfly valves are suitable for pipelines conveying various corrosive and non-corrosive fluid media in engineering systems such as generator, coal gas, natural gas, liquefied petroleum gas, city gas, cold and hot air, chemical smelting, power generation and environmental protection, etc. They are used to regulate and cut off the flow of media. Butterfly valves are classified as handle butterfly valves, turbine butterfly valves, pneumatic butterfly valves and electric butterfly valves.
6. Ball valve means
Ball valve refers to a valve that uses a ball with a round through hole as an opening and closing part, and the ball rotates with the valve stem to realize the opening and closing action. Standard GB/T21465-2008 “Valve Terminology” is defined as a valve whose opening and closing part (sphere) is driven by the valve stem and rotates around the axis of a square ball valve. It can also be used for fluid regulation and control, in which the V-shaped ball valve with hard seal has strong shear force between the V-shaped ball core and the metal valve seat with cemented carbide surfacing, which is especially suitable for media containing fibers and tiny solid particles. On the pipeline, the multi-port ball valve can not only flexibly control the confluence, diversion and flow direction switching of medium, but also close any channel and connect the other two channels.
7. Check valve
Check valve, also known as one-way valve or non-return valve, is used to prevent the media in the pipeline from flowing backwards. The bottom valve of water pump suction switch is also a check valve. There are two types of forged steel check valves: the first type is the forged steel check valve with bolted body cover. The valve designed according to this type of connection has the advantages of bolt connection between valve body and valve cover and winding gasket sealing. The second type of forged steel check valve with full welded cover, the valve designed according to this connection form, its valve body and valve cover are connected by screw mosquito, and are fully welded and sealed, with the advantage of no leakage.
8. Balance valve
Balance valve is a kind of valve with special function, which can adjust the balance dynamically and statically under hydraulic conditions. In some industries, because the medium (all kinds of flowable substances) has a large pressure difference or flow difference in various parts of pipes or containers, in order to reduce or balance the difference, balance valves are installed between the corresponding pipes or containers to adjust the relative balance of pressure on both sides, or achieve the flow balance by means of shunt.
9. Float valve
The ball float valve automatically controls the liquid level of water tower or pool by crank arm and float ball. It is simple to maintain, flexible and durable, and has high accuracy of liquid level control. The water level is not interfered by water pressure, and it is tightly opened and closed without water leakage.
10. stop valve
The stop valve (GlobeValve), also known as a shut-off valve, is one of the most widely used valves. The valve lever applies pressure to the sealing surface of the disc and the sealing surface of the valve seat, which causes them to be closely attached and prevents the medium from flowing. Because the medium only flows in one direction, it has directionality during installation. Globe valves can be divided into DC globe valves, angle globe valves, plunger globe valves, upper threaded stem globe valves, lower threaded stem globe valves, etc. They have the characteristics of durability, small opening height, easy manufacture and convenient maintenance, and are not only suitable for medium and low pressure, but also suitable for high pressure.
