Level Control Valves, Capillary tubes
Capillary tubes are used for the control of pressure and temperature in the refrigerating installation. They are most often used for household refrigerators, coolers of milk, ice cream parlours, and smaller units. Commercial refrigeration and used by other devices. Capillary tube consists of a tube with a very small diameter. Tube length depends on the block size to be served, refrigerant, as well as other physical considerations. Order to implement the necessary heat transfer, this tube is usually soldered to the suction line between the condenser and the evaporator. Capillary tube acts as a regular throttle or limiter on the refrigerant. Its length and diameter to offer adequate resistance to the flow friction refrigerant build to a head pressure required for the condensation of the gas.
If the condenser and evaporator were just linked big pipes, pressure, they can adapt quickly to the same value in both of them. Small diameter pipes of water will keep the water, allowing the pressure will be built in the water, but with a small velocity.
Similarly, the small diameter of the capillary tube hampers the liquid refrigerant. This allows high pressure, which should be created in the condenser during operation of the compressor. At the same time, it allows the refrigerant to flow slowly into the evaporator (see Fig. 11-42). Filter-drier as a rule, is inserted between the condenser and the capillary tube. This is necessary because the line or the tube is so small that it easily clogged.
Replacement should be performed in the store after the discharge device. In the capillary tube replacement, make sure the length of pipe used. The diameter of the hole or inner diameter must be exactly the same as the old tube. It is easy to check with the right tool.
Discharge Of Hot Gas Bypass Valves
Hot gas may be required for other systems, functions, in addition to bypass the power control. Hot gas may be necessary to defrost and head pressure. Generally, these functions will not interfere with each other. However, compressor low suction pressure may be experienced at system startup, when the discharge-bypass valve works and other functions require the hot gas. For example, head-pressure control requires of hot gas pressure, since the receiver and liquid line to get a thermostatic expansion valve is working properly. In this case, the discharge-bypass valve must be prevented from functioning, maintaining the hot gas solenoid valve is closed until sufficient liquid line or suction pressure is obtained.