英文S2014_ノンブル無し_高
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EXPANSION VALVES GENERAL INFORMATIONVALVE SELECTIONIn order to properly select Expansion Valves, the following items should be considered.1)Required valve capacity should be based on the actual system operating conditions rather than the normal valve capacity rating.2)When there exists an appreciable pressure drop between the valve outlet and the evaporator outlet, i.e., above 0.02 MPa {0.2 kgf/cm2}, or when a pressure drop type of refrigerant distributor is used at the evaporator inlet, the valve should have the external equalizer feature for best performance. Otherwise, it will increase a static superheat (valve opening temp.), restricting the refrigerant flow and causing the reduction of system capacity. As for R134a, 0.01 MPa {0.1kgf/cm2} pressure drop will increase the static superheat approximately 1°C.3)Internally equalized valve may be used with the evaporator which has a negligible pressure drop, i.e., below 0.02 MPa {0.2 kgf/cm2}GUIDE FOR EQUALIZER (Internal or External)An internal or external equalizer should be selected depending on pressure drop between valve outlet and evaporator outlet. Internal equalizer increases superheat in the refrigeration system of which evaporator has some pressure drop, and the increase of superheat decreases the effective area of evaporator.Select internal or external equalizer depending on refrigerant, pressure drop and evaporating temperature. The Guide Table for Equalizer indicates the pressure difference of refrigerant corresponding to 1°C temperature. The external equalizer valves should be used when the pressure drop exceeds the value of pressure difference indicated in the Table.GUIDE TABLE FOR EQUALIZERPressure Diff. corresponding to 1°C temperature.Unit: MPa {kgf/cm2}RefrigerantEvaporating Temperature (°C)1050−5−10−20−30−40−50−60R134a0.014 {0.14}0.012 {0.12}0.011 {0.11}0.009 {0.09}0.008 {0.08}0.006 {0.06}0.004 {0.04}0.003 {0.03}——R220.024 {0.24}0.02 {0.20}0.018 {0.18}0.016 {0.16}0.014 {0.14}0.011 {0.11}0.008 {0.08}0.006 {0.06}0.004 {0.04}0.003 {0.03}R404A0.025 {0.25}0.022 {0.22}0.019 {0.19}0.017 {0.17}0.015 {0.15}0.012 {0.12}0.008 {0.08}0.006 {0.06}0.004 {0.04}0.003 {0.03}R407C0.021 {0.21}0.018 {0.18}0.016 {0.16}0.014 {0.14}0.012 {0.12}0.009 {0.09}0.006 {0.06}0.004 {0.04}0.003 {0.03}0.002 {0.02}R410A0.033 {0.33}0.029 {0.29}0.026 {0.26}0.023 {0.23}0.020 {0.20}0.015 {0.15}0.011 {0.11}0.008 {0.08}0.006 {0.06}0.004 {0.04}

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