Static evaporation pressure-hold test device and method for vehicular LNG (liquefied natural gas) cylinders

Abstract

The invention discloses a static evaporation pressure-hold test device for vehicular LNG (liquefied natural gas) cylinders, which is characterized by comprising a base; a test tube is arranged on thebase; the front end of the test tube is connected with an emptying tube of a cylinder under test; the rear end of the test tube is connected with a gas recycling line; a heater, a thermometer, a pressure meter, a flowmeter and a low-lift safety valve are arranged on the test tube sequentially from front to rear; a full-lift safety valve and an emptying stop valve are arranged on the test tube between the pressure meter and the flowmeter. The whole device herein is directly connected with a heat-insulating cylinder line; connecting the components sequentially to the cylinder line as in the prior art is not required; assembly time is saved, and it is avoided that multiple assembly and disassembly affects airtightness between the components.

Description

technical field [0001] The invention relates to a static evaporation rate test of an insulating gas cylinder, in particular to a static evaporation rate test device and a test method for a vehicle-used LNG gas cylinder. Background technique [0002] With the release and implementation of GB / T 34347-2017 "Periodic Inspection and Evaluation of Cryogenic Insulated Gas Cylinders", there is a relatively unified method for the periodic inspection of LNG cylinders for vehicles nationwide. In this standard, the non-disassembly method has been allowed for the inspection of LNG cylinders for vehicles, and the inspection test is directly based on the LNG medium. The test device is to install a vent pipe valve, a temperature riser, a thermometer, and a gas mass flow meter in sequence on the vent pipe of the tested part. The test process is as follows: After filling the adiabatic cylinder with liquid, stand still for at least 48 hours, open the vent valve during the period of rest → con...

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Problems solved by technology

[0005] 1. During the test, the above components need to be assembled on the pipeline of the gas cylinder in sequence. The assembly time is long and the airtightness is poor after repeated disassembly and assembly; 2. There is a heating device behind the pressure controller without a pressure gauge, and the pressure controller has pressure After that, it is not necessarily normal pressure, and the volume expansion is caused by the temperature difference caused by the temperature rise. The volume density of the evaporation volume of the medium under the pressure environment before the pressure controller changes after the pressure controller, so the recorded flow value is distorted, resulting in The measured data has a large error; 3. After the measurement, the whole set of equipment contains high pressure, and there is no pressure relief measure. The disassembly process is operated under pressure, and the safety of the operator cannot be guaranteed; 4. Only a single pressure is changed, not changed Other parameters, and under different pressure conditions, the physical parameters of the medium are very different, such as calculating α according to the original formula 20 Can't get real data

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