Specification for selection and installation of refrigeration piping parts for chillers

Specification for selection and installation of refrigeration piping parts for chillers

The accessories of the refrigeration pipeline of the chiller mainly include various valves and connectors. Depending on the refrigeration system, the chiller's request for piping accessories is also different. If the refrigeration piping accessories are not selected correctly, or the device does not meet the requirements, it will directly affect the cooling effect of the chiller.

　　 One, valve

　　Various valves should use special products that fit the refrigerant. The valves used in the ammonia system chiller should meet the following requirements:

　　 1. The valve body is gray cast iron, temperable iron or cast steel. The strength test pressure is 29~39bar, and the tightness test pressure is 19~25bar. Usually a valve with a nominal pressure of 24.5 bar can meet the requirements.

　　2. The valves used in the ammonia system chiller are not allowed to have copper, galvanized, and tin-plated parts.

　　 3. The valve should have a reverse valve seat, and when the valve is fully opened, the packing can be replaced during operation.

　　 2. Connecting parts

Ammonia system chiller pipes are mainly welded, and the pipe wall thickness is less than 4mm with gas welding, and the pipe wall thickness is more than 4mm with electric welding. If necessary, flange connection can also be used. Single flanges should have high and low openings; all elbows should be simmered; The connection of the valve and the pipe thread shall not use white linseed wire, and the packing of pure pure glycerin and yellow powder should be used; when the branch pipe is connected to the header box, the branch pipe should be connected with the header with an arc-shaped fork to avoid liquid distribution Uneven.

In the Freon refrigeration system, its connection method is: steel pipes and steel pipes are welded, steel pipes and copper pipes are silver welded, copper pipes and copper pipes are silver welded, and the pipe wall should not be galvanized, and the flanges should not be used with natural rubber , Do not apply mineral oil, and its sealing materials should be corrosion-resistant materials, usually nitrile rubber.

　　 3. Request for installation of chiller pipe fittings and accessories

　　1. Elbow: When cold bending, the radius of curvature should not be less than 4 times the tube outer diameter;

　　2, Tee: A downstream tee should be used, and an oblique tee can also be used for the Ya-shaped horn elbow;

　　3. Valves: All kinds of valves should be special products suitable for refrigerants. The expansion valve used in the chiller of the Freon refrigeration system should be placed straight, not skewed, and not to be inverted;

　　4. Thermometer: It must have a metal protective sleeve. When it is installed on the pipeline, its mercury (or alcohol) ball should be on the pipeline base line, and the temperature sensing end of the sleeve should face the direction of fluid movement;

　　5. Pressure gauge: high pressure vessels and pipelines should be equipped with 0~2.5MPa pressure gauges, medium and low pressure vessels and pipelines should be equipped with 0~1.6MPa pressure gauges;

　　6. ​​Temperature sensing bag: installed on a straight pipe 1.5m away from the suction pipe of the chiller.