Difference between common valves and central air conditioning valves.

The principles of central air conditioning include: 1. Refrigeration principle of central air conditioning: compression type, absorption type, etc. , which will not be described here; Second, the principle of central air conditioning system: the working principle of ventilation system, water system and coil system. , briefly introduced as follows:

1, working principle of fresh air system of central air conditioning:

Outdoor fresh air is sucked into the air cabinet by the air handler, filtered, cooled and dehumidified, and then sent to each room through the air duct. At this time, fresh air can not meet the indoor heat and humidity load, but can only meet the indoor fresh air demand. Because the indoor fan coil unit handles the heat and humidity load of indoor air, a part of the excess air is discharged outside through the return fan according to the valve opening ratio, and a part is returned to the air inlet for recycling. As shown in the figure:

2 1. vacuum valve: absolute pressure

2. Low-pressure valves: valves with nominal pressure PN≤ 1.6MPa (including steel valves with PN≤ 1.6MPa) (cast iron, stainless steel, etc. ).

3. Medium pressure valve: a valve with a nominal pressure of PN 2.5-6.4 MPa. (Mainly cast steel and stainless steel)

4. High-pressure valve: a valve with a nominal pressure of PN 10.0-80.0 MPa. (Cr-Mo steel, cast steel, high-temperature acid-resistant steel)

5. Ultra-high pressure valves: valves with nominal pressure pn ≥ 100.0mpa (Cr-Mo steel, cast steel)