SU1791712A1 - Device for measuring gas consumption - Google Patents

Description

The invention relates to measuring equipment, namely to measuring gas flow, and can be used to control and measure the flow characteristics of various devices, as well as in automated systems for the experimental study of gas equipment,

A known gas flow meter containing a valve, a measuring tank, a pressure repeater, interconnected with each other and with the supply line. The disadvantage of this device is the significant error in measuring gas flow at low pressures.

A device for measuring gas flow rate is known, comprising a switch, a measuring tank, a pressure repeater, a chamber divided by a membrane, and a pressure regulator in communication. However, the presence of mechanical connections and the absence of an accurate reading device reduces the speed of the device and increases the measurement error of small gas flow rates.

The closest technical solution is a gas flow meter, containing a supply line with a switch connected to the first input of the pressure repeater, with a second input and output, a measuring tank with an input, a first electrical circuit with a switch connected to the first input of the time meter, the second input of which is connected with a second electrical circuit with a switch, as well as a reference pressure source. The disadvantage of this device is the decrease in accuracy characteristics due to the inertia and friction of the mechanical element in the measuring tank and the unreliability of the designs of the measuring tank, in which, as parts wear, gas overflow is possible.

The purpose of the invention is to improve the accuracy of measurements in the range of low costs.

1791712 4

The goal is achieved in that in a device for measuring gas flow, which contains a supply line with a switch connected to the first input of the pressure repeater, with a second input and output, a 5-dimensional tank with an input, a first electrical switch, connected to the first input of the time meter , the second input of which is connected to the second electric circuit’s circuit breaker, as well as the 10th reference pressure source, a comparison unit, a setter, a pneumatic-electric converter, an actuator, and a third electric circuit are introduced and a delay element, wherein the first input of the comparison unit 15 is connected to the output of the pressure follower and the input of the measuring tank, the second input of the comparison unit is connected to the output of the setter, and the output is connected to the input of the pneumatic-electric converter, the actuator 20 is installed in the switch and connected to the third electric circuit, which is connected to the second electrical circuit through a switch, the output of the pneumatic electroconverter is included in the first electrical circuit 25, the second input of the meter is connected to the second electrical circuit through ement delay, while the second input is connected with a pressure repeater feed line and the setpoint input 30 co-one with a source of reference pressure.

Figure 1 schematically shows a device for measuring gas flow, in which one line shows the gas channels, the double - electrical circuit; Fig. 35 figure 2 is a combined diagram of the response of the elements of the device with graphs of pressure measurement in their cavities.

A device for measuring gas flow (Fig. 1) contains a supply line 1 40 with a switch 2 connected to the first input of the pressure follower 3, the output of which is connected to the input of the measuring tank 4 and the first input (chamber A) of the comparison unit 5. Application of the comparison unit 45 in the form of a three-membrane element U SEPA allows you to record the end of a filled measuring tank to a given pressure level with high accuracy. Product I is connected to the supply line 1 and to the input of the switch 50 of switch 2, in which it is necessary to measure the gas flow. The supply line 1 and the second input (control chamber) of the pressure follower 3 are connected to a reference pressure source 55 (not shown). To the second input of the block (chamber B) of comparison 5, a setter 6 is connected, the input of which is connected to a reference pressure source. The chamber B of the comparison unit 5 is connected to the reference pressure source, as well as to the chamber G connected with the atmosphere, forming the output of the comparison unit 5, connected to the input of the pneumatic electroconverter 7, the output 5 of which is connected through the first electric circuit with the switch 8 to the first input of the time meter 9 The connection of a self-adjusting pressure follower 3 between the I product and the aroma measuring tank 10 allows maintaining a constant gas velocity in the channels and thereby establishes a linear dependence of the filling time of the measured p the tank from the measured flow rate, which additionally 15 increases the accuracy of the measurement. The second input of the time meter 9 is connected to the second electric circuit 10 and the switch 11 through the delay element 12. The switch is controlled by the 20 actuator 13 installed therein, coupled to the third electric circuit 14, which is connected to the second electric circuit 10 through the switch 11.

A device for measuring gas flow is as follows. At the command of switching on 11, the control signal enters through the third electrical circuit 14 to the actuator 13. The switch 2 is triggered 30 and gas is opened through the supply line 1. product 14. pressure repeater 3 to the measured tank 4. Simultaneously with the start of filling the measured tank 4 with gas the electric signal 35 from the switch 11 through the delay element 12, by means of which the required time delay is set, will be supplied via the second electric circuit 10 to the second input of the time meter 9, which will start 40 counting. At the initial moment of operation of the device, the pressure in the chamber A of the comparison unit 5 corresponds to atmospheric pressure, and the pressure in the chamber B corresponds to the pressure set by the pressure adjuster 6, therefore, the membrane block of the unit 5 of the comparison 5 is in the upper position and the connection of the chamber B with the reference pressure source is closed. Since the chamber G is in communication with the atmosphere, the pressure at the output of the comparison unit 5 is also equal to atmospheric, and there is no signal at the output of the pneumatic electro-converter 7. As the gas in measuring tank 4 is filled with gas, pressure also increases in chamber A, when it reaches a pressure equal to 55 times the pressure in chamber B, which will correspond to the required level of gas filling in measuring tank 4, the membrane unit in the comparison unit will move down. The communication of camera G with the atmosphere is interrupted. In the chamber B, therefore, a signal in the form of pressure will also appear at the output of the comparison unit 5, which will be converted into an electrical signal in the pneumoelectronic converter 7. He enters through the first electrical circuit with a switch to the first input of the time meter 9 and stops the countdown. Since the rate of increase in pressure in the measured tank 4 is proportionally dependent on the flow rate through the product And located in the line of the supply line 1, the time between switching on the switch 2 (with appropriate adjustment by the delay element 12) and the operation of the comparison unit 5 will be proportional to the flow rate through the product And that is fixed by a time meter 9. At the end of each measurement of gas flow, the electrical signal from the switch 11 is removed.

The operation of the device for measuring gas flow is illustrated by a combined diagram (figure 2). At the initial moment, i.e. before the operation of switch 2, the pressure in the supply line 1, in the product And, at the second input (in the dead control chamber) of the pressure follower 3 will be equal to Pi. Moreover, at the second input (in the input chamber) of the repeater, the pressure I overpressure will be zero, because this input before the operation of the switch 2 is connected to the atmosphere (figure 1). After the switch 2 is activated, the pressure Рг = Ρι - Δ is set at the first inlet (in the input chamber) of the pressure repeater 3, which is set by the pressure repeater adjustment element 3. Due to this, the pressure Рz is at the inlet of the pressure repeater 3, the measuring tank 4 and the first inlet (chamber A) of the comparison unit 5 will vary linearly. Diagram P? reflects a transient process in a system containing a delay link, consisting of a switching line, stray capacitances and a drive 13. Diagrams Rzad and P _c illustrate the operation of the comparison unit 5: as soon as the pressure P ₃ in the chamber A reaches the pressure Rzad set in the chamber 6 in the chamber B, at the output of the comparison unit, the pressure Pc appears. necessary for the operation of the pneumatic electroconverter 7. The pressure rise time P ₃ corresponds to the measurement time t _u . The time constant T ₃ set by the delay element 12 compensates for the time constant T1 of the delay link, thereby increasing the accuracy of the measurement.

Claims (1)

Claim A device for measuring gas flow, comprising a supply line with a switch connected to the first input of the pressure repeater with a second input and output, a measuring tank with an input, a first electrical circuit with a switch connected to the first input of the time meter, the second input of which is connected to the second electrical circuit with a switch, as well as a source of reference pressure, characterized in that. in order to increase the accuracy of measurements in the low-flow range, a comparison unit, a setter, a pneumatic-electric converter, an actuator, a third electric circuit and a delay element are introduced into it, while the first input of the comparison unit is connected to the output of the pressure follower and the input of the measuring tank, the second input of the comparison unit is connected to the output of the setter, and the output is connected to the input of the pneumatic electroconverter, the actuator is installed in the switch and is connected to the third electric circuit, which is connected to the second The electrical circuit via the switch, pnevmoelektropreobrazovatelya output included in the first electrical path, a second time meter input connected to the second electric circuit via a delay element, a second input of the pressure repeater is connected to the feed line and the set point input coupled to a source of reference pressure. FIG. Z Compiled by V. Barabanov Editor Tehred M. Morgenthal Corrector M. Keretsman Order 147 Circulation Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035. Moscow. Zh-35, Raushskaya nab., 4/5 Production and Publishing Plant “Patent, Uzhhorod, 101 Gagarin St.