Low-temperature liquefied gases include liquid hydrocarbons (such as ethylene), liquefied petroleum gas (LPG), liquefied natural gas (LNG), liquid oxygen, liquid nitrogen and other low temperature liquefied gas. The temperature of these media is usually -30 ~ -l96 â„ƒ, the pump conveying these media is called cryogenic pump or cryogenic pump, magnetic pump. Today's latest valid order information free to send! Morning latest buyers information free to send! Punch grab Rob here! First, the characteristics of cryogenic pumps 1. High pressure at the pump inlet Liquefied gas is normally at ambient temperature and atmospheric pressure and becomes liquid only under certain pressure and low temperature conditions. Such as ethylene plant, liquefaction of methane is 3MPa, -l00 â„ƒ; ethylene liquefaction conditions of 2MPa, -30 â„ƒ. 2. Vapor pressure changes sharply with temperature Liquefied gases delivered by cryogenic pumps are usually saturated (or with a slight subcooling). The vaporization pressure of this liquid has a very significant temperature change. Generally when the temperature changes Â± 25%, the vaporization pressure can change Â± (100 0A ~ 200%), meanwhile the physical properties such as density, specific heat capacity, latent heat of vaporization will also change. For example, when the temperature rises, the vapor pressure increases sharply, the density decreases, the specific heat capacity increases, the latent heat of vaporization decreases, the liquefied gas is more easily vaporized, and the inlet pressure is increased, which affects the strength of the pump body; Vapor pressure within the tank decreases, but also through the suction tube è”«, but also easy to absorb heat from the outside heat, which will result in NPSH. Of the decline, the deterioration of inhalation cavitation performance, and therefore must be fully insulated suction pipe cold, so that the suction tank temperature fluctuations do not often. Pipeline at the same time should try not to set spherical lanthanum, throttling, filters and other throttling device, so as not to cause local pressure drop, the liquefied gas vaporization. 3. Strict requirements on the shaft seal Most liquefied gases are corrosive and dangerous, so do not allow leakage to the outside world; once liquefied gas leak bitch. As the liquefied gas vaporization heat easily lead to the sealing parts of the icing, cryogenic pump delivery of liquefied gas on the shaft seal of the very strict requirements.
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