Gas constant-flow output feedforward control apparatus and gas constant-flow output feedforward control method

Abstract

The present invention relates to a gas constant-flow output feedforward control system, which comprises a gas storage tank, an operation station, a PLC controller, a regulating valve, a stop valve and a pressure sensor, wherein the pressure sensor is arranged inside the gas storage tank, the output pipeline of the gas storage tank is sequentially provided with the regulating valve and the stop valve, and the PLC controller is connected with the operation station, the gas storage tank and the regulating valve. The method comprises that: the PLC controller detects the initial tank pressure and the temperature of the gas storage tank, and controls the regulating valve according to the control information transmitted by the operation station, and the PLC controller controls the stop valve to close when the gas output is not required. According to the present invention, the structure is simple, the control method is relatively simple and easy to perform, and the gas with the constant mol / s-grade flow can be output.

Description

technical field [0001] The invention relates to a feed-forward control system and method for constant gas flow output, in particular to a system and method for open-loop control of constant output of gas flow in a pipeline according to the differential form of the Clapeyron equation and the gas flow equation in the pipeline. Background technique [0002] At present, in order to make the gas in the pipeline output at a constant flow rate, there are several ways in the project: (1) install a steady flow device (such as a Venturi tube) in the pipeline; (2) install a pressure stabilizing valve in the pipeline; (3) ) to design the control algorithm by itself. Among them, the first method requires that the upstream pressure of the device is sufficiently large and constant, but in fact, the saturated vapor pressure of some gases determines that the gaseous pressure cannot be increased infinitely, and, unless the gas storage tank is large enough, as the gas Outflow, the upstream pr...

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Problems solved by technology

Among them, the first method requires that the upstream pressure of the device is sufficiently large and constant, but in fact, the saturated vapor pressure of some gases determines that the gaseous pressure cannot be increased infinitely, and, unless the gas storage tank is large enough, as the gas Outflow, the upstream pressure cannot be kept constant, especially when the gas flow rate is large; although the second method can adjust the output pressure in a closed loop (and then control the output flow), it is only applicable to mmol / s flow, and is rarely applicable to mol / s-level gas flow output device; the advantage of the third method is that a more suitable control algorithm can be designed according to the model of the controlled object to make the flow output constant, and the feedback control method is usually used, but there are also the following disadvantages: (1 ) Gas turbulence often makes the collection amount fluctuate greatly, which affects the output value of the actuator; (2) The control of feedback control lags behind the collection, and there is a response delay in the control valve of the control actuator, which increases the difficulty of control

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