SU1691550A1 - Device for automatic determination of capacity of pumping units - Google Patents

Abstract

The invention relates to the transportation of a substance, preferably a liquid or gas, by means of pumping units and is intended for the automatic and continuous determination of their productivity. The purpose of the invention is to improve the accuracy of flow measurement. The device contains working pipeline 1, input 2 and output 4 collectors, pumping unit 3, stop valves, electronic computing device 19 with sensors and control elements connected to it, measuring pipeline with a sample flow meter 14 and shut-off valves 14 with its output connected to the output collector 4, and the input to the input collector 2 of the pumping unit 3, while at the entrance of the pumping unit 3 there is a koffuzor 7 installed, equipped nny sensors 10 8- differential pressure, pressure and temperature. 1 il.

Description

The invention relates to the transport of substances, mainly liquid or gas, using pumping units and is intended for automatic and continuous determination of their performance.

A device is known for automatically measuring pump performance, comprising a measuring tank having an inlet and drain pipe with shut-off valves at the bottom, indicators of the upper and lower levels of the measured capacitance, a pulse counter on the drain pipe and a computer unit for counting pulses and displaying the results on the display.

The device allows you to measure the pumped substance in relatively small portions and is designed to measure small capacities of pumping units operating in intermittent mode, for example, fuel pumps, and cannot be used to measure the flow of material through units of high capacity and continuous operation, for example, pumps of turbine units for pumping large quantities liquid or gas.

Also known are devices for measuring the flow rate of liquid or gaseous substances, containing a straight section of the pipeline, a constriction device, differential pressure, pressure and temperature meters of the substance on the constriction device.

The disadvantages of devices of this type include significant energy losses on the narrowing device installed in the working pipeline, and the Inability to provide a straight section (of the pipeline of the required length before entering the pumping unit. In connection with this, the flow coefficient of the narrowing device varies within the limits that depend on the parameters of the measured substances.

The closest in technical essence to the invention is a device for determining the performance of pumping units, containing a working pipeline, input and output collectors, a pumping unit, valves fittings ^ electronic computing device.

- According to the measurement results, the flow rate of the substance (Q) through the pumping unit is determined by the formula

Q- K 7AP ~, (1)

At where K is the flow coefficient of the confuser;

Δ P is the measured value of the differential pressure on the confuser;

γ is the specific gravity of the pumped substance in front of the supercharger.

The disadvantage of the described device is the instability of the coefficient, the flow rate of the confuser due to the inability to provide a sufficient length of the straight section of the pipeline in front of the confuser, necessary to stabilize the flow of matter. The degree of flow instability depends both on the configuration of the pipeline in front of the confuser, which may be different for each specific case, and on the parameters of the pumped substance, differential pressure, pressure and temperature. In this regard, when changing the parameters of a substance over a wide range, the flow coefficient also changes. confuser, which leads to large errors.

The purpose of the invention is to improve the accuracy of flow measurement.

This goal is achieved by the fact that the device for automatically determining the performance of pumping units, containing a working pipeline, input and output manifolds, a pumping unit, shut-off valves, an electronic computing device with sensors and control elements connected to it, is additionally equipped with a measuring pipe with an exemplary flow meter and shut-off valves, and the exemplary flow meter with its output is connected to the output manifold, and the input ohm - to the inlet manifold of the pumping unit, the inlet of the pumping unit installed converger equipped with pressure sensors, differential pressure and temperature.

The drawing shows a diagram of the device.

The device comprises a working pipe 1, an input manifold 2, a pumping unit 3, an output collector 4, an input 5 and an output 6 of the nozzle of the pumping unit 3, a confuser 7, a differential pressure sensor 8, a pressure sensor 9, a temperature sensor 10, an input 11 and output 12 nozzles of the measuring pipeline 13, an exemplary flow meter 14, shut-off valves 15-18, electronic computing device 19.

The device operates as follows.

When the shut-off valves 15-18 and the idle pumping unit 3 are open, the substance of the working 1 and measuring 13 pipelines is filled. Then, the electronic computing device 19 is turned on in the graduation mode of the confuser 7. For this, the shut-off valves 15. 16 are closed and the pumping unit 3 is started. As the pumping unit 3 accelerates, several modes of its operation are established and stabilized at several intermediate speeds (for example, 0, 75; 0.85; 0.95; 1.05) p _n , where p _n is the nominal rotation speed of agr / ata.

At each operating mode of the pumping unit 3, using the sensors 8-10 and an exemplary flow meter 14, the parameters of the substance on the confuser 7 are synchronously measured, namely: differential pressure (ΔΡ), pressure (P), temperature (t), as well as the flow rate of the substance ( Q). The results of the measurements are introduced into the electronic computing device 19, where a matrix of measurement results is compiled:

Qi; APi; Pi; ti Q ₂ ; Δ P ₂ ; P ₂ ; t ₂ Qi; Δ Pi; Pi ti Omi APm; Pm, 'tm where. m is the total number of measurement series in all operating modes of the pumping unit.

After the measurement cycle in the electronic computing device 19, the following calculations are performed: for each series of measurements I from the formula (1) calculate the flow coefficient of the confuser ^):

for liquid substances

Ki = Qi V pH // h; (2)

Δ Pi for gaseous substances

Ki = Qi V PhTiZi; (3)

ΔΡι · PT where / He is the specific gravity of a substance under normal conditions;

βι \ is the temperature coefficient of density change for a liquid;

Ζι is the gas compressibility coefficient; Τι is the absolute temperature of the gas.

I.

After determining the flow coefficient of the confuser in the electronic computing device 19, a new matrix is compiled:

Ki; Qi: ΔPi; P1: ti K ₂ ; Q ₂ : Δ P ₂ ; P ₂ ; t ₂ Ki, -Qi; ΔΡι; Pi ti Km, 'Qm; APm Pm.'tm from which the coefficients of the regression equation for the flow coefficients of confuser K are calculated by the least squares method:

K = a + 6Δ P + cP + d t, (4) where a, .- b, s, d is the coefficient of the regression equation.

At this point, the graduation mode of the confuser 7 ends, the electronic computing device 19 opens the shut-off valves 15, 16, closes the valves 17, 18, and the pumping unit 3 is turned on for normal operation on the pipeline 1. At the same time, the electronic computing device 19 is introduced synchronously from sensors 8-10 of a series of measurements ΔΡ, P, t, where the corresponding value of the flow coefficient of the confuser K. is calculated

Therefore, the performance of the pumping units is determined: for liquid substances:

Q = K: (5)

Ρπβτ for gaseous substances

Thus, improving the accuracy of measuring the performance of pumping units is achieved by establishing a more accurate value of the flow rate of the confuser for each specific unit, a specific connection scheme and specific parameters of the pumped substance.

Performance measurements of pumping units in normal operation using this device do not lead to additional energy costs and are fully automated.

Claims (1)

Claim A device for automatically determining the performance of pumping units, containing a working pipeline, input and output collectors, a pumping unit, shut-off valves, an electronic computing device with sensors connected to it 7. 1691550 8 and valve control elements, characterized in that, in order to improve the accuracy of flow measurement, the device is additionally equipped with a measuring pipeline with a standard 5 flow meter and shutoff valves, and the model flow meter with its output connected to the output manifold, and the input to the input manifold of the pumping unit, while at the inlet of the pumping unit there is a confuser equipped with pressure, differential pressure and temperature sensors.