【 Weak current College 】 refrigeration process safety design should note the following aspects

1, because ammonia combustible and explosive, therefore in the compresses room design, ammonia gas detection instruments, so that it is equipped with explosion-proof motor blower chain, when there is a trace of ammonia leak at the open air, at the same time alarm. Fan air volume per hour shall be not less than 12 times the volume of the engine room. Ammonia instrumentation expensive, approximately $/point.

2. compression engine room-low and medium pressure container level in the control of the most important, if liquid ultra high will cause the compressor knock, malignant accident, level control based on "should not be used any one of the only instrument at the same time into the control and protection of the" principle, the level control and alarm are located on the second set of separate instruments.

3, in cold storage rooms, cooling and freezing compartment is no longer set ammonia valve, but in order to reduce investment, General valve located in the cooler outside air in the upper part of the Library Board. Especially with hot ammonia automatic defrosting cooler, as short valve and the distance between the evaporator.

4. split workshop and packaging rooms and other places, in order to ensure their personal safety, do not use ammonia direct evaporative cooling devices. Small establishments with freon system, the larger the refrigerant with ethylene glycol, although construction investment is higher, but safe and reliable. If you must use ammonia directly evaporate, you must connect to the evaporator, special requirements, the pipeline and ammonia gas measuring instruments were found, exhaust, alarm device, ensure personal security.

5 pipes insulation should be embarrassed-fuel or not combustion, there is not distributed on food contamination by material, generally use polyurethane, outsourcing aluminum skin geqi, polyurethane shall conform to the following specifications: density: 40 ~ 50kg/M3; thermal conductivity: 0.031W/M.0C; compressive strength greater than or equal to 20N/cm2; flexural tensile strength greater than or equal to 24.5N/cm2; water absorption is less than or equal to 3g/100cm2; self-extinguishing not greater than 7s. Where self-extinguishing not greater than 7S on fire safety, not the most important.

6. the design should also clearly indicate that the pipeline should weld inspection requirements, temperature is higher than-29 degrees centigrade, weld inspection shall not be less than 5%, but in order to guarantee access for construction quality, General requirements for the design of the description is not lower than 10-20%, higher than GB50235-97 the industrial metal pipe construction and acceptance. For temperatures below-29 degrees centigrade of piping should be 100% radiographic examination, its quality may not be lower than class ⅱ. Therefore in pipe reducer, three links, etc. are made of forged pieces, and rolled seamless pipes, can guarantee the construction quality, reduced weld failure rate.