In the design process of stainless steel cryogenic valves, in addition to the general requirements such as the flow capacity and flow channel resistance of stainless steel cryogenic valves, some other indicators need to be considered in order to better evaluate the technical level of cryogenic valves. The performance of stainless steel cryogenic valves is usually evaluated by measuring whether the energy consumption is reasonable. The main evaluation indicators are as follows.
1. Insulation performance of stainless steel cryogenic valve
The adiabatic capacity of the low-temperature valve can be measured by the mass ratio of the heat flow Q1 entering the low-temperature medium and the passing low-temperature medium. However, when the type of medium remains unchanged and only the flow rate changes, its value will change, so it is obviously inappropriate to use this method as an index for evaluating the thermal insulation capability of low-temperature valves. The indicator KT can be used for unified comparison.
In the formula: P -- the heat entering the low temperature medium per unit time, W, P=Q1/T;
αT -- proportional coefficient, considering that low-temperature valves are generally tested in liquid nitrogen, αT=0.0216;
ΔT -- the difference between the ambient temperature (20°C) and the temperature of the low temperature medium, °C;
DN -- nominal diameter of the valve, m.
The KT value is an approximate constant for the same medium, which is only related to the properties of the valve itself.
2. Cooling performance of stainless steel cryogenic valve
The cooling performance of the cryogenic valve refers to the ability of the cryogenic valve to cool from normal temperature to working temperature. This performance can be measured by the energy consumed by the valve in the above-mentioned process, that is, the heat Q2 transmitted by the valve to the low-temperature medium in the above-mentioned process. The cooling performance index is extremely important for the low temperature valve that works periodically. However, it is not enough to use Q2 to measure the cooling performance of low temperature valves. The following indicators can be used:
3. Working performance of opening and closing seals of stainless steel cryogenic valves
Under low temperature conditions, the performance of seals is often damaged. In order to achieve reliable sealing, a reasonable sealing structure must be adopted or the specific pressure of the seal must be increased. Therefore, the sealing effect needs to be evaluated.
Parameters related to leakage can be used to measure the sealing ability of cryogenic valves, namely:
In the formula, ΔV -- the average leakage of gas during the working life, m3/s.
4. The condition that the surface of stainless steel cryogenic valve does not freeze
When the low temperature valve is working, its surface should not condense, let alone freeze. Whether the outer surface of the valve freezes depends first on the difference ΔT1 between the ambient air temperature and the surface temperature of the part, and secondly on the dew point temperature of the air. In fact, under all weather conditions, it is difficult to completely eliminate condensation. However, if ΔT1 meets certain conditions, the possibility of icing will be greatly reduced, and the condition for no icing on the valve surface is ΔT1≤5℃.
Stainless Steel Cryogenic Valve Supplier - XINLIANTONG
Chengdu XinLianTong cryogenic equipment Co.,Ltd founded in 2006,We are the scientific and technological enterprise mainly engaged in the manufacture and development of High vacuum stainless steel cryogenic valve and other stainless steel cryogenic equipment. The company is willing to advance hand in hand with new and old customers sincerely, establish friendly cooperative relations, also sincerely welcome new and old friends come to XINLIANTONG !
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