Installation steps and attentions for valves in industrial cold water chiller refrigerating systems
In the refrigeration system of industrial chiller, the main function of valve is to control the flow and direction of refrigerant. Valve also need to be used frequently in daily life. The valve is used when the industrial chiller is shut down or opened. Due to its high frequency of daily use, more attention should be paid to the installation to ensure its normal use without affecting the stability of the industrial chiller. The following I will introduce you the installation procedures and attentions of refrigerating system valves in industrial cold water chillers.
- The valve should be installed in the place where it is easy to disassemble and maintain. The flow direction of refrigerant must be paid attention to when installing all kinds of valves.
- When installing flanged valves for industrial water coolers, flange pieces and valve flanges must be padded with high pressure asbestos board, whose thickness shall be determined according to the depth of flange groove on the valve. When valves are large and have deep grooves, thicker asbestos sheets should be used to avoid gaps between their concavo-convex joints and loose sealing. When assembling flanged valve, make sure all bolts are uniformly forced, otherwise the concavo-convex joint is easy to bias.
- When install globe valve, working medium should flow from valve bottom to the top. When installed on a horizontal pipe line, the stem should be vertical or inclined at a certain angle, and the stem should not be downward. If the valve position is difficult to approach or relatively high, the stem can be installed horizontally for operation convenience.
- When installing check valves for industrial chillers, make sure that the spool can be opened automatically. For elevation type check valves, the center line of the spool shall be mutually perpendicular to the horizontal plane. For swing type check valves, the rotation of the disc should be guaranteed and the disc must be horizontal.
- The safety valve should be installed directly at the outlet of the globe valve equipment. The arrow on the valve body should be the same direction as the flow direction of the working medium.
- The solenoid valve must be installed horizontally at the outlet of the equipment and must be installed at the position specified in the drawing. If the solenoid valve is installed in front of the throttle valve, the distance between the two should be at least 300mm.
- The thermal expansion valve in the industrial chiller must be installed horizontally. The inlet and outlet connections of the valve should be noted, usually there’s a strainer at the inlet end of the valve. If the thermal expansion valve is well controlled, the position of temperature sensor is very important. The temperature wrap should be firmly fixed on the clean air pipe, so that the temperature wrap can have good contact with the air pipe. The external balance pipe of the external balance thermal expansion valve shall be installed at the lower part of the return pipe temperature sensing package lapping, and the distance from the temperature sensing package lapping is 150~200mm. The Thermal package should be tied to the horizontal pipe segment, and the external balance pipe should be connected from the top of the horizontal pipe segment of the return pipe.
How to vent industrial chiller
- When the air is released by the air separator, place the return valve of the air separator in the normally open state to reduce the pressure of the air separator to the air intake pressure. Other valves should be closed.
- Properly open the mixed gas inlet valve to allow the mixed gas in the industrial cold chiller refrigerating system to enter the air separator.
- Slightly open the water supply valve, so that the refrigerant throttles into the air separator to gasify heat absorption, cooling mixture gas.
- The rubber hose used to connect the vent valve port to insert one end into the water of the water container. When the refrigerant in the mixed gas is cooled to ammonia, the air separator will frost at the bottom. At this time we can open the air valve slightly, and the air will be discharged through the water container. If the air bubble is round in the process of rising in the water and there is no volume change, the water is not cloudy and the water temperature is not rising, the gas released is air . At this time, the open degree of the vent valve should be appropriate.
- The cryogen in the mixed gas is gradually condensed into cryogen liquid and deposited at the bottom. The liquid height can be seen from the frost condition of the shell. When the liquid level reaches 12, close the liquid supply throttle and open the liquid return throttle valve, to make the underlying refrigerant fluid return to the air separator to cool the mixture gas. When the frost layer at the bottom is about to finish melting, close the return throttle and open the supply throttle valve.
- When stopping the air release, close the air release valve to prevent the coolant from leaking out, and then close the water supply throttle valve and the mixed gas inlet valve. The return valve should not be closed to prevent pressure rise in the vent.
How to deal with the cold water non – circulation problem?
Generally speaking, there is a cold water circulating pump in the small industrial chiller, while large scale without it. At this time, when assembling the cold water system, a cold water circulation pump shall be installed externally. So that the cold water after absorbing the heat of the cooling equipment, will return to the inside of the chiller for cooling. In other words, the cold water supply back pipeline forms a circulation system.
It is important to note that the recommended location of the cold pump is lower than the water level of the water storage tank (pond), whether the cold pump is built in or out. Do like this circulation pump can take in the cold water well. In some cases, however, the cold water storage tank may be required or restricted by the installation environment, which may cause the cold water circulation pump to be higher than the water level of the reservoir. Then, the cold water system often fails to absorb water during operation, which leads to the fault of insufficient cold water flow in the chiller. The manufacturer can inquire the cause of the fault on the control panel of the chiller, and the solution steps are as follows:
- Use hose from cold water storage casks (pool) back to the hydrating tubular pipe on cold water circulating pump to fill water in (open small valve ), open the small gas plug of the cold water circulation pump with a wrench (screw it again if there is water coming out), until there’s backwater returns to the pipe of the water storage tank (pond). And then pull out the rubber tube to see if there is air bubble. If yes, continue filling until there is no bubble and close the small valve.
- At this point, turn on the chiller for 1-3 minutes. If there is a large amount of water back to the pond, that means there’s no problem.
- If the backflow water is not enough or there is no water back, repeat the above irrigation action.