RU2493542C1 - Automated information system for control of industrial pumping complex with vertical electric centrifugal pumps for pumping of sewage drain water - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: system is additionally equipped with an electric centrifugal pump electric motor control unit, temperature sensors, to measure temperature of bearings and vessel of the electric centrifugal pump, a sensor for measurement of vibration of the pump set, a data transmission system. The data transmission system combines outputs of all sensors and messages with an information centre comprising a PC and a data base of measured parameters. On the basis of these parameters, pressure is measured at the inlet of the electric centrifugal pump, which characterises liquid level in the electric centrifugal pump sump.

EFFECT: simplified process of measurement and analysis of vertical electric centrifugal pump parameters and specified pump system parameters in a real time mode.

7 dwg

Description

The invention relates to the field of wastewater disposal, containing various impurities, using pumping complexes with vertical electric centrifugal pumps, at pumping stations of water utilities of cities and industrial facilities with the measurement and taking into account the number of pumped sewage.

Modern sewage pumping systems are complex engineering structures, which are characterized by the following development trends: increasing the capacity of sewage pumping plants, increasing the reliability of working installations, timely detection of possible breakdowns of installations.

All these features of modern sewer water drainage systems complicate their operation mode and require a different approach to managing them. Further improvement of sewage disposal systems is associated with the solution of a number of major problems requiring new scientifically based technical, economic and technological solutions. The most important of these problems is the introduction in the networks of an automated information system for receiving and analyzing in real time, at the control room, the main indicators in the operation of vertical electric centrifugal pumps in order to maintain their operation in optimal mode. The main parameter characterizing the operation of vertical electric centrifugal pumps is: flow rate. All known devices for measuring the flow rate of a liquid in which various substances are located do not solve this problem.

A device is known, including measuring the mass flow rate and density of a liquid containing various impurities. The device consists of pressure sensors at the inlet and outlet of the pump and a sensor for measuring the active power consumed by the vertical pump / Patent No. 2119148 of the Russian Federation. A method of measuring the mass flow rate and density of a liquid supplied by a centrifugal electric pump. / Krichke V.O., Groman A.O., Krichke V.V., from 20.11.97. However, this device does not consider an automated information system for measuring the flow rate of a vertical electric pump of a liquid containing various impurities.

The essence of the invention is the optimization of the operation of vertical electric pumps when pumping liquids with various mechanical impurities with obtaining and analyzing in real time the main performance indicators of vertical electric centrifugal pumps in order to maintain their operation in optimal mode.

The technical result is a simplification of the process of measurement and analysis in real time of the parameters of the vertical electric centrifugal pump and the specified parameters of the pumping system.

The technical result is achieved by the fact that in the well-known automated information system for controlling a pump and pipeline complex with vertical electric centrifugal pumps for pumping sewage, containing pumping stations with devices for measuring the pressure generated by electric centrifugal pumps, devices for measuring the electrical power consumed by electric motors of electric centrifugal drives pumps, the feature is that it is additionally equipped with a control unit ia for switching the rotational speed of the shaft of the vertical electric centrifugal pump, devices for measuring the temperature of the body of working electric centrifugal pumps, devices for measuring the vibration of the bodies of electric centrifugal pumps and a system for transmitting data from all devices to an information center containing a computer and a database of measured parameters, using which it is measured the pressure at the inlet of the electric centrifugal pump, which characterizes the liquid level in the pit of the electric centrifugal pump, while Control lock switched on depending on the liquid level in the pit, from which electric centrifugal pump takes liquid further includes an appropriate performance and calculated power, acting on the pump shaft N, by multiplying the power consumed from the network F _with the efficiency of the motor η _ed and η _n electrocentrifugal pump calculated pressure generated by an electric centrifugal pump p _n, by subtracting the output pressure of the pump p _O electrocentrifugal pressure p at the input _Rin, by na Tailor data calculated value consumable Mo coefficient at zero flow at the beginning of the performance when operating electrocentrifugal pump closed valve taken from the working characteristics of the pump, a pressure dividing result p ₀₁ on power M ₀₁ obtained experimentally at the time of calculation of operational coefficient η _eq determined deviations of power N and pressure p from the nominal values and over the entire range of the rating characteristic, the resulting deviations in power and pressure are taken into account in the operation of the electric centrifugal pump and the operating coefficient is determined according to the characteristic, the volumetric flow rate and pressure N are determined by the pressure of the pumped liquid, by dividing the effective pressure created by the electric centrifugal pump by the effective design pressure N and coefficient g, the efficiency of the electric centrifugal pump is calculated pressure by multiplying the result of dividing by power consumption, the specific energy consumption _ud W by dividing the density by a factor of the effective action of the electric centrifugal pump and the electric motor with the corresponding coefficient, the temperature and vibration of the electric centrifugal pump housing are measured by the devices, the calculated data on the transmission system are sent to the control room in the computer, which contains the appropriate database, with the help of which all the necessary information for measurement and analysis is calculated in real-time key performance indicators of the pumping station.

The proposed automated information system for measuring and analyzing in real time the main indicators in the operation of a pumping station with vertical electric centrifugal pumps during sewage pumping, containing pumping units with pressure sensors and power sensors, is additionally equipped with an electric motor control unit for an electric centrifugal pump, temperature sensors for measuring temperature of bearings and housing of an electric centrifugal pump, sensor for measuring vibration the pump installation, a data transmission system that combines the outputs of all sensors and messages with an information center containing a computer and a database of measured parameters, using which the pressure at the inlet of the electric centrifugal pump is measured, which characterizes the liquid level in the pit of the electric centrifugal pump, the higher the level, with a large flow rate, it is necessary to pump the liquid, the control unit turns on and, depending on the liquid level in the pit from which the pump takes the liquid, the corresponding speed the rotation of the pump shaft, and therefore its productivity, and the power acting on the pump shaft N is calculated by multiplying the power consumed from the network P _c by the efficiency of the electric motor η _ed and η _{n of the} pump, the pressure created by the pump r _{n is} calculated by subtracting the pressure at the pump outlet pressure p _O p on its input _Rin by passport data calculated value consumable Mo coefficient at zero flow at the beginning of the performance of the pump to a closed valve, taken from the working Pump Characteristics result p ₀₁ pressure division by power of M ₀₁ obtained experimentally at the time of calculation of operational coefficient η _eq power offset determined by the N and p the pressure from nominal values throughout the range of the rating characteristics obtained deviation power N and pressure p are recorded in the characteristic pump and the operating coefficient η _ec . Determined volumetric flow rate Q, and thereon head H and the density p of the pumped fluid by dividing the differential pressure created by the pump P _n on the current design head H and the coefficient g, calculated pump efficiency efficiency _n by multiplying the pressure p _n to the result of dividing the flow Q by power N, specific electric energy consumption W _beats by dividing the density p by the efficiency of the electric centrifugal pump η _n and the electric motor with the corresponding coefficient, the temperature is measured by devices Parameter T and vibration of the casing of the electric centrifugal pump, the calculated data on the transmission system are sent to the control room in the computer, containing the corresponding database, with the help of which all the necessary information for measuring and analyzing in real time the main performance indicators of the pumping station is calculated.

The drawings show:

Figure 1 General view of a vertical electric centrifugal pump SDV 2700 / 26.5.

Figure 2 Passport performance characteristics of the vertical electric centrifugal pump SDV 2700 / 26.5.

Figure 3 Recalculated operating characteristics of the pump for its maximum shaft speed SDV 2700 / 26.5 740 rpm for the schedule.

Figure 4. The increased recalculated characteristics of the pump for its maximum speed of rotation of the pump shaft SDV 2700 / 26.5 740 rpm for the schedule.

Figure 5. New discharge characteristic of the pump SDV 2700 / 26.5 740 rpm M-Q.

6 A new discharge characteristic of the pump SDV 2700 / 26.5 740 rpm Q-M.

Fig. 7 Measurement schemes for pressure p, temperature T, power E and vibration В of a pump installation with a vertical electric centrifugal pump: а) - using portable devices or devices located on the pipeline, b) - measurement scheme with a telemechanics system, control unit - block control the electric motor of the pump drive to transfer to one of three speeds with a synchronous number of revolutions of the shaft of the electric centrifugal pump

A General view of a vertical electric centrifugal pump SDV 2700 / 26.5 shown in figure 1

Structurally, the pump consists of a centrifugal electric pump 1, which is placed in the pit 2, from which liquid is pumped out, an electric motor 3, located on the surface on the supports 4, which is connected to the electric centrifugal pump by the shaft 5. The liquid is sucked through the pipe 6, and the liquid is supplied through the pipe 7. The pressure at the pump inlet is measured at the inlet of the nozzle 6, and the output pressure is measured at the outlet of the nozzle 7. The electric motor of the electric centrifugal pump works as a synchronous electric motor with the possibility of eklyucheniya three synchronous speed. When switching speeds, it is necessary to take off, when starting the pump with its valve closed, the pressure and power values and calculate the operating coefficient from them and build three operating characteristics with the corresponding shaft speed of the electric centrifugal pump.

Figure 2 shows the factory operating characteristic of a vertical electric centrifugal pump SDV 2700 / 26.5, according to which all other characteristics were made in the future. The recalculated operating characteristic of the electric centrifugal pump for the maximum shaft rotation speed is given in Fig. 3 and with an increased parameter in Fig. 4.

Performance characteristics of the vertical electric centrifugal pump SDV 2700 / 26.5 with a synchronous speed of 740 rpm

Consumption, Q m ³ / h Power, N kW Head, N m Pressure, p kg / cm ² Pump efficiency,% 0 75.1 37.3 36.7 0 500 125 38 37.3 40 1000 167 37 36.3 60 1500 204 36 35.3 70 2000 241 32 31,4 75 2500 265 28 27.5 76 3000 271 24 25 75 3500 272 19.5 19.5 70 4000 271 17 16.7 64

Performance characteristics of the vertical pump SDV 2700 / 26.5 with a synchronous speed of 740 rpm and a flow coefficient M

Consumption, Q m ³ / h Power, N kW Head, N m Pressure, p kg / cm ² Consumption coefficient, M kW / kg / cm ² Pump efficiency,% 0 75.1 37.3 36.7 2.04-2.04 0 500 125 38 37.3 1.31 40 1000 167 37 36.3 2,56 60 1500 204 36 35.3 3.66 70 2000 241 32 31,4 5.63 75 2500 265 28 27.5 7.63 76 3000 271 24 25 9.45 75 3500 272 19.5 19.5 12.26 70 4000 271 17 16.7 16.23 64

Data for the construction of flow characteristics

Consumption, Q m ³ / h Consumption coefficient, M kW / kg / cm ² Consumption, Q m ³ / h 0 2.04-2.04 0 0 500 1.31 500 1000 2,56 1000 1500 3.66 1500 2000 5.63 2000 2500 7.63 2500 3000 9.45 3000 3500 12.26 3500 4000 16.23 4000

Performance characteristics of a vertical electric centrifugal pump SDV 2700 / 26.5 with a synchronous speed of 740 rpm and a flow coefficient M with coefficients for graphical construction of an information system

Consumption, Q m ³ / h Power, N kW Head, Nm Pressure, kg / cm ² Consumption coefficient, M kW / kg / cm ² Pump efficiency,% 0 37.5 186.5 183.5 0 0 500 60 190 186.5 13.1 80 1000 84.8 188.8 182.7 25.6 120 1500 102.6 181.4 176.5 36.6 140 2004 120.5 163.6 157 56.3 155 2500 132.5 140 135.6 76.3 153.2 3000 135.5 120 113.8 94.5 150 3500 136 96.5 92 122.6 140 4000 135.5 85 81 162.3 128

Organization of work of the automated information system under consideration.

1. Have a passport operating characteristic of the pump unit in question. Figure 2.

2. To calculate the new flow rate characteristics M - Q, using the rating characteristics for power and pressure,

figure 3, figure 4 M = (N / p) η _ek -N ₀ / p _about . kW / kg / cm ² and according to the calculated data to build on the general characteristics of the graphics MQ and QM figure 5, figure 6 and give their mathematical description. In this formula N / p, the effective power and pressure values over the entire range of characteristics, η _ek are the operational coefficient, N ₀ / p ₀ are the power and pressure parameters at the beginning of the pump performance.

3. To calculate and build graphs of pressure on the parameters of the passport pressure characteristics, Fig.5 and Fig.6.

4. The operating coefficient η _{ek is} determined

η _ec = (N ₀ / p ₀ ). (p ₀₁ / N ₀₁ ), where (p ₀₁ / N ₀₁ ) - respectively, the experimental data on pressure and power at the moment when the electric centrifugal pump operates on a closed valve for one minute at its launch.

5. According to experimental data, we determine the pressure p _n created by an electric centrifugal pump,

p _n = p _out -p _in , kg / cm ²

6. We measure the power consumed by the electric centrifugal pump from the network, by power sensors or by calculation, according to line current 1, A and line voltage U, V in a three-phase network

N = √3 IU cos φ η _ed η _n kW

7. Taking into account the efficiency of the electric motor η _ed and the electric centrifugal pump η _n , cos φ = 0.88, η _ed = 0.97, η _n = 0.9.

8. According to the received data, we measure the power acting on the shaft of the electric centrifugal pump

N = 1.73. 40.6000. 0.88.0.97. 0.9 = 292.46 kW

9. The pressure created by the electric centrifugal pump p _n , p _n = p _out- p _in = 66.7-36.7 = 30 kg / cm ^{2 is} calculated

10. When starting the electric centrifugal pump with the valve closed, the pressure p ₀₁ and power N ₀₁ 0 are also calculated

p ₀₁ = 37 kg / cm ² , N ₀₁ = 76 kW

11. The operating coefficient is calculated

η _e = (75.1 / 36.7). (37/76) = 0.98%.

12. The calculated expenditure coefficient M, which is equal to

M = ((N / p) 0.98-N ₀ / p ₀ ), kW / (kg / cm ² ), where

M = ((292/30) 0.98-69.69 / 35.44) = 8, kW / (kg / cm ² ),

13. The volume flow Q is determined according to the schedule or by calculation according to the equation shown in the graph of this figure.

According to the schedule Q = 2700 m ³ / h

14. Determine the efficiency η _n electric centrifugal pump

η _n = (p Q 10 ⁶ ) / 102. 3600 N _H %, where p is the pressure created by the electric centrifugal pump kG / cm ² , N _H is the rated power from the rating of kW, Q is the measured flow

η _n = p. Q 10 ^5/102 3600 N _nom,%, p is the pressure - in kg / cm ²

η _n = ^{(30.2700 10 5/102 3600 270} = 81.2 %

15. Determine the density of the pumped liquid

p = pg H = 1000 9.81.26.5 10 ^-6 = 261 kg / m ³

16. Determine the mass flow rate Q _m

Q _m = P Q 10 ^-3 t / h = 261 2700 10 ^-3 = 704.7 t / h

17. We determine the specific energy consumption, assuming the pressure N = 1 m, the flow rate Q = 1000 t, and the power consumed by the drive motor from the network N, we obtain the specific energy consumption of the pump unit W _beats

W _beats = 2.724 / η _H η _el.dv. kWh // 1000 tm, where g / 3.6 = 2.724, and

η _n and η _el.dv - respectively η _n electric centrifugal pump and efficiency

η electric _{twin of the} electric motor W _beats = 2.724 / 0.812 0.97 = 3.44 kWh / 1000 tm

18. When pumping a liquid with a different specific gravity, the specific energy consumption is

W _beats = 2.724 p. 10 ^-3 / η _n η _el.dv kWh / 1000 tm

The electric centrifugal pump can operate on one of three rating characteristics. At the same time, for each characteristic, its own calculation is carried out similar to that which is done for the first characteristic. When switching the pump to a new characteristic, it is necessary to observe high accuracy in the revolutions of the pump shaft in accordance with the rating values.

Knowing the specific energy consumption allows you to objectively assess the state of the pump unit and to take timely measures to resolve possible malfunctions in its operation.

Information sources

1. Patent No. 2119148 of the Russian Federation. A method of measuring the mass flow rate and density of a liquid supplied by a centrifugal electric pump. / Krichke V.O., Groman A.O., Krichke V.V. from 11/20/97.

Claims (1)

An automated information system for controlling a pump and pipeline complex with vertical electric centrifugal pumps for pumping sewage water, containing pumping stations with devices for measuring the pressure generated by electric centrifugal pumps, devices for measuring the electric power consumed by electric motors of electric centrifugal pump drives, characterized in that it is additionally equipped with a control unit for switching the vertical shaft speed of an electric centrifugal pump, devices for measuring the temperature of the body of working electric centrifugal pumps, devices for measuring the vibration of the bodies of electric centrifugal pumps and a system for transmitting data from all devices to an information center containing a computer and a database of measured parameters, using which the pressure at the inlet of the electric centrifugal pump is measured, which characterizes liquid level, in the pit of the electric centrifugal pump, while the control unit turns on depending on the liquid level in the method from which the electric centrifugal pump takes fluid, then the corresponding capacity is turned on and the power acting on the pump shaft N is calculated by multiplying the power consumed from the mains P _s by the efficiency of the electric motor η _ed and η _{n of the} electric centrifugal pump, and the pressure created by the electric centrifugal pump is calculated pump r _n , by subtracting from the pressure at the outlet of the electric centrifugal pump, p _out pressure at its inlet p _in , the value of the flow coefficient is calculated from the passport data M ₀ at zero flow rate at the beginning of the operating characteristic when the electric centrifugal pump is operated by a closed valve, taken from the operating characteristic of the pump, the result of dividing the pressure p ₀₁ by the power M ₀₁ , obtained experimentally at the time of calculation, the deviations of power N and pressure are determined from the operational coefficient η _ek p from the nominal values and in the entire range of the rating characteristic, the resulting deviations in power and pressure are taken into account in the characteristics of the electric centrifugal pump, and the operating ion coefficient, according to the characteristic, the volumetric flow rate is determined, and according to it, the pressure Н, and the pressure density of the pumped liquid by dividing the effective pressure created by the electric centrifugal pump by the effective pressure rating Н and coefficient g, the efficiency of the electric centrifugal pump is calculated by multiplying the pressure by the result dividing the flow rate by power, specific electric energy consumption W _beats by dividing the density by the efficiency of the electric centrifugal pump and electric motor the device with the corresponding coefficient, the temperature and vibration of the casing of the electric centrifugal pump are measured using the devices, the calculated data on the transmission system are sent to the control room in the computer containing the corresponding database, with the help of which all the necessary information for measuring and analyzing in real time the main indicators is calculated pump station work.

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