RU2475682C2 - Automated information system for real-time measurement and analysis of main properties of operation of pump stations with centrifugal electric pumps in water supply and water discharge systems - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: system comprises the following: pressure sensors at the pump inlet and outlet, static power converter, temperature sensors and vibration measurement sensor and ratings of the pump together with a new flow rate characteristic Q=f(M). System is equipped with data transfer system, as per all controlled parameters, to the dispatch station equipped with the computer containing the data base for all measured parameters; received information is transferred via data transfer system to the dispatch station to be analysed and stored.

EFFECT: automated information system provides continuous monitoring and analysis of each pump unit, volumetric and mass flow rate of pumped liquid, pressure created with the pump, consumed power, efficiency coefficient of the pump, specific consumption of electric power, time to failure, bearing temperature of the pump house, pump housing temperature and vibration level.

Description

The invention relates to the field of water supply and sanitation of cities and industrial facilities and can be used to measure and account for water flow in order to regulate the water supply and sanitation.

Modern water supply and sanitation systems are complex engineering structures, which are characterized by the following development trends:

- an increase in the power of pumping units for pumping liquid;

- increased requirements for the quality of drinking water;

- the use of long-standing pumping units with a change in their performance;

- improving the reliability of operating installations;

- timely detection of possible breakdowns of pumping units with the prevention of the development of an accident;

- improving the efficiency of the pumping units by the timely determination of the drop in efficiency;

- timely determination of the increase in specific energy consumption;

- timely determination of temperature increase in bearings and pump housing, which will prevent the development of an accident.

All these features of the development of modern water supply and sanitation systems complicate the mode of their work and require a different approach to managing them.

Further optimization of the operation of water supply and sanitation 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, which is used to obtain and analyze in real time, at the control room, the main performance indicators of pumping stations in order to maintain their operation in optimal mode. The main parameter characterizing the operation of the pumping unit is the flow rate. All known devices for measuring flow rate contain primary sensors that are directly in contact with the measured liquid and require periodic inspection and calibration at the stands, which complicates their operation.

A device is known that includes measuring the mass flow rate and density of a liquid, consisting of pressure sensors at the pump inlet / outlet, a sensor for measuring the active power consumed by the pump drive motor, and a device for calculating a measured flow rate parameter / Patent 2119148 RF Method for measuring 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 / [1].

However, this patent does not address an automated information system for water pumping stations.

The essence of the invention is to optimize the operation of the water supply and sanitation system by obtaining and analyzing in real time the main performance indicators of pumping stations in order to maintain their operation in optimal mode.

The technical result is a simplification of the process of measuring and analyzing in real time the parameters of pumping units and the entire automated information system.

The technical result is achieved by the fact that the well-known automated information system for measuring and analyzing in real time the main performance indicators of pumping stations with centrifugal electric pumps in water supply and sanitation systems, containing pumping stations with pressure sensors and power sensors, is additionally equipped with temperature sensors for measuring temperature bearings and pump housing and a sensor for measuring the vibration of the pump unit, a data transmission system that combines you ode all sensors and messages from data center comprising a computer and a database of measured parameters, using which calculates the power exerted on the shaft of each pump is N, by multiplying the power consumed from the network F _with the efficiency of the motor η _al, pressure is calculated, p generated by the pump, by subtracting the pressure at the pump outlet pressure p _O p on its input _Rin by passport data calculated value consumable coefficient M ₀ at zero flow at the beginning of the performance, by dividing the power N ₀ by pressure p ₀ , the operating coefficient η _ek is determined experimentally when the pump is operated by a closed valve, by multiplying the result of dividing the power N _o by pressure r _o , when the pump is operated by a closed valve, taken from the pump performance, the division result measured pressure values p _o1 on the measured power of the pump shaft N _o1, power offset determined by the operational coefficient η _eq ± ΔN and pressure ± Ap from the nominal values and in the entire range of passport Characteristics obtained deflection power and the pressure added to the pump performance power N ± ΔN and pressure p ± Ap, calculated over the entire range of passport data estimated consumable ratio M _p, without the coefficient convergence K, by multiplying the power division result N ± ΔN the pressure value p ± Δp, the operating coefficient η _ek , minus the value of the expenditure coefficient M ₀ , a graph of the dependence of the passport expenditure coefficient M on the calculated M _p expenditure coefficient M = f (M _p ), in the period from measurements, according to the calculated value of M _p according to the characteristic

M = f (M _p ), the actual expenditure coefficient M is determined, and according to the graph Q = f (M), the volume flow Q is determined when determining the flow using the convergence coefficient K, which is determined over the entire range of characteristics, by dividing the passport expenditure coefficient M by estimated expenditure coefficient M _r , and graphs K = f (M _r ) or K = M / M _{r are} plotted, using the found value of K, the expenditure coefficient M is calculated by the formula, by dividing the convergence coefficient K by the calculated expenditure coefficient M _r , by the calculated value R of the flow coefficient Q = f (M), the volumetric flow rate Q is calculated, the pressure characteristic HQ is calculated at the calculated flow rate, the effective head H, and the density p of the pumped liquid over it, by dividing the effective pressure created by the pump by the effective design head H and ratio g, calculated pump efficiency by multiplying the result of pressure on the flow dividing power, the specific power consumption W _beats, by dividing the density ratios helpful about the action of the pump and the motor with the corresponding coefficients, the temperature on the pump bearings and the temperature of the pump housing are measured using the sensors, and the vibration amplitude is measured by the vibration measuring sensor, the calculated data on the transmission system are sent to the control center in a computer containing the corresponding database, with with the help of which all the necessary information is calculated for measuring and analyzing in real time the main performance indicators of pumping stations.

In the proposed automated system, the current measurement of the parameters of pumping units is carried out with data being transmitted to the control room in a computer containing the appropriate database, with the help of which all the necessary information for measuring and analyzing in real time the main performance indicators of the pumping stations is calculated, which allows timely acceptance measures to eliminate possible deviations in the operation of pumping units from predetermined modes that can lead to accidents of pumping units and disrupting the whole automated information system.

An automated information system provides continuous monitoring and analysis of each pump unit by measuring the volumetric and mass flow rate of the pumped liquid, the pressure generated by the pump, power consumption, efficiency, specific energy consumption, MTBF, temperature of bearings at the pumps, temperature of the pump housing, level vibrations. For this, the system contains: pressure sensors at the inlet and outlet of the pump, a static power converter in the electrical network, temperature sensors and vibration measurement sensors. The system is equipped with a data transmission system for all controlled parameters to a control room with a computer containing a database of all controlled parameters, with which all the necessary data are calculated.

The drawings show:

Figure 1 General view of the pumping station 2 NFS "Samaravodokanal".

Figure 2 Scheme of a pumping station 2 NFS "Samaravodokanal".

Figure 3 Performance characteristics of the network pump 18 VAT.

Figure 4 Consumption characteristic of the Q-M pump 18 VAT.

Figure 5 Consumption characteristic of the M-Q pump 18 VAT.

6 Performance characteristics of the network pump 14 VAT.

Fig. 7 Flow characteristic of the Q-M pump 14 VAT.

Fig. Consumption characteristic of the M-Q pump 14 VAT.

Fig.9. The characteristic dependence of the passport expenditure coefficient M from the calculated M _p .

Figure 10 Characteristic dependence of the coefficient of convergence K from the estimated expenditure coefficient M _r .

11 Functional diagram of the automation of one pump, where the following notation is accepted: TT - 1, 2, 3 - besklakalnye temperature sensors; K _t - temperature sensor controller; RT - 4, 5 - pressure sensors; To _d - controller pressure sensors; ET - 6 - static power converter; K _e - power sensor controller; VT - 7 - vibration sensor; K _in - controller of vibration sensors; Computer IP - computer information point in the pump room; Computer DP - a computer at the central control center.

Fig. 12 Experimental graphs for measuring the flow rate of water for two days supplied by the pumps 14 VAT and 18 VAT at the pumping station 2 of the NFS "Samaravodokanal" and the flow rate of the water meter.

Fig. 13 Experimental graphs for measuring the flow rate of water for two days supplied by pumps 14 VAT and 18 VAT at the pumping station 2 of the NFS Samaravodokanal.

Modern water supply and sanitation systems consist of pumping stations, water sources, pumping units, trunk lines and consumers. At the pump station 2NFS1, the general view of which is shown in Fig. 1, and in the diagram in Fig. 2, there are 6 pumping units driven by electric motors, the parameters of the pumping units are given in tables 1, 2.

Table 1 Passport data of pumps at the pump station 2NFS1 Pump brand Delivery, m ³ / hour Head, m RPM power, kWt Efficiency% D working wheel mm Bearing No. 18 VAT 2500 62 985 450 87 700 318 14 VAT 2307 62 1450 420 88 510 312 18 VAT 2500 62 985 450 87 700 319 14 VAT 2307 62 1450 420 88 510 312 14 VAT 2307 62 1450 420 88 510 312 14 VAT 2307 62 1450 420 88 510 312

table 2 Passport data for electric motors of pumps 2NFS1 Email engines Motor type power, kWt RPM Voltage Worker current, A Efficiency% Cosφ Async. A4-4005-8U3 250 750 6000 36.7 93.5 0.88 Async. A355X-4 315 1585 6000 46.2 93 0.88 Async. A4-4005-8U3 250 750 6000 36.7 93.5 0.88 Async. A4-4005-8U3 315 750 6000 46.2 93 0.88 Async. A4-4005-8U3 315 750 6000 46.2 93 0.88 Async. A133-4M 250 1480 6000 36.7 93 0.88

At the pumping station, two types of pumps are used: 14 VAT and 18 VAT. The pump performance is shown in FIG. 3 and FIG. 8. In these characteristics, new consumable characteristics are given in accordance with RF patent No. 2119148. The flow characteristic is based on the passport characteristics of the pump. As drive motors, the pumps can be synchronous, in which the speed does not depend on the load, and asynchronous, in which the speed depends on the load. When using a synchronous electric motor, the nameplate characteristic of the pump remains unchanged. If asynchronous motors are used, then the passport characteristic must be recalculated in accordance with the frequency of rotation of the motor shaft. During operation, the parameters of the pumping unit can take values other than the passport ones, in these cases, the performance must be recalculated. Therefore, in the future we will use concepts such as passport and basic characteristics. Under the base we mean the characteristic obtained experimentally or recalculated passport taking into account the operating parameters of the pump, affecting the characteristic, for example, a change in speed, diameter of the impellers. Depending on the load of the pump motor. So, recalculation of the characteristics of the pump when driving from an induction motor is performed according to the reduction formulas:

for flow: Q ₁ / Q ₀ = (n ₁ / n ₀ ) or Q ₁ = Q ₀ (n ₁ / n ₀ );

или

for pressure:

or

или

for power:

or

where Q ₁ , H ₁ , N ₁ , n ₁ - current values of flow, pressure, power, pump shaft rotation frequency, and Q ₀ , Н ₀ , N ₀ , n ₀ - their passport values, respectively.

The construction of a new characteristic is as follows. When driven by a synchronous electric motor, all primary data is taken from the nameplate characteristic. When driving from an asynchronous electric motor, at first, the passport characteristics are recalculated according to the reduction formulas discussed above. First, the pressure characteristic pQ is constructed according to the pressure Н. To do this, using the known fluid density p, according to which the passport characteristics were built, the pressure characteristic pQ is calculated and built over the entire range, calculated by the formula p = ρgH, Pa, p = ρgH10 ^-6 , MPa, where N, m - head, g = 9.81 m / s ² or p = ρgH10 ^-5 / 102, kg / cm ² .

Then, the flow coefficient M _{0 of the} constant component of the pump flow characteristic is calculated by dividing the power N ₀ on the pump shaft by the pressure p ₀ created by the pump when the pump is running on a closed gate valve at its outlet

M ₀ = N _o / p _o , kW / (kg / cm ² ),

the flow coefficient M is calculated by the formula and is included in the overall pump performance.

M = ((N / p) η _ek - (N _o / p _o )) K, kW / (kg / cm ² ),

where η _ek is the operational coefficient characterizing the deviation of the operating performance of the pump from the nameplate value, K is the coefficient of convergence of the design characteristic of the pump with the nameplate.

If the passport characteristic has not changed, then the coefficients K and η _ek are taken equal to unity. Then, according to the flow characteristic Q-M with the calculated flow coefficient M, the volume flow Q _{0 is} determined.

Figure 3 shows the performance of the pump 18 VAT. The main characteristics of the pump are the dependence of the power NQ, the pressure Н-Q and the pump efficiency η _у - Q on the pump capacity Q. To these characteristics is added a new flow characteristic M-Q. The flow characteristic can be built in the function Q-M (figure 4) or in the function MQ (figure 5). For a mathematical description of the flow rate, the Q-M dependence is used. 6, 7, 8, similar characteristics of the VAT pump 14 are given.

To obtain the necessary information on managing the water supply and sanitation system, there are information points (Fig. 11), which are connected through a communication network to a central information point, on which computers with a database are located. At the same time, to obtain the necessary information, it is necessary to have data for each pumping unit — flow rate Q, pressure p, power N, pump efficiency, specific electricity consumption W _beats , mean time between failures and vibration level of pumping equipment. Of these data, the most important parameter is the flow rate Q of each pump unit. In the system under consideration, the feed is measured directly by a working installation. The system is equipped with a data transmission system, for all controlled parameters, to a control room with a computer, which contains the necessary database for all controlled parameters. Using computer calculated: power by multiplying the measured power P _with the efficiency of the motor η _ed pressure p generated by the pump, by subtracting the output pressure of the pump P _O pressure at its input p _Rin measure vibration and temperature of the pump bearings and the housing, characteristic of the passport is calculated consumable coefficient M ₀ by dividing the power of the pump acting on N ₀ on the shaft the pressure p ₀ at the beginning of the performance at zero flow, the experimental data at the pump the closed valve during its start is determined service factor η _eq, by multiplying the result of dividing the power N _o by p _o, of the pump of the closed valve, taken from the pump performance, the result of dividing the measured pressure values p _o1 to a value of power to the pump shaft N _o1, consumable calculated coefficient multiplying the result by M rms power division by the pump shaft in the pressure developed by them, on the service factor η _eq minus the result of dividing power, act her pump N _o shaft to produced them pressure p _o, at closed valve at the outlet of the pump and the multiplied result of the subtraction to the convergence coefficient K which is pre-calculated by the performance of the pumping unit, which based on the calculated value of the service factor η _eq determine deviations from nominal values of power ± ΔN acting on the pump shaft during its operation on a closed gate valve with zero flow rate and the pressure developed by it ± Δp, and add them in the rating sheet to the power values N ± ΔN, the pressure developed by the pump p ± Δp, in the entire range of pump characteristics calculate the calculated flow coefficients M _p with convergence coefficients K equal to unity, according to the formula:

M = ((N / p) η _ek - (N _o / p _o )) K, kW / (kg / cm ² ),

calculate the convergence coefficient K by dividing the passport value of the expenditure coefficient M, taking into account this operating coefficient η _ek , by the calculated calculated expenditure coefficient M _p , build a graph of the dependence of M on M _p , calculate the convergence coefficients K by dividing the passport expenditure coefficients M by the calculated consumables _Mp coefficients and build characteristic K-M _p depending on the convergence coefficient K calculated operational coefficient M _p, computed current ratio M consumable by mind dix current consumption coefficient M _p by convergence coefficient K, or M _p -M characteristic, when a certain current consumption coefficient value M _p are consumable coefficient M, and thereon, using Q-M characteristic calculating volumetric flow rate Q _o, by with the pressure characteristic HQ, the effective pressure H is calculated with the calculated flow rate, and the density p of the pumped liquid, the specific energy consumption W _beats , are calculated according to the formulas:

power N acting on the pump shaft

N = P _c η _ed , kW;

pressure generated by pump p

p = p _out -p _in , kg / cm ² ;

flow coefficient M ₀ constant component of the flow rate characteristics of the pump

M ₀ = N ₀ / p ₀ , kW / (kg / cm ² )

operating coefficient η _ek

η _ec = (N ₀ / p ₀ ). (p ₀₁ / N ₀₁ )

the current expenditure coefficient M is equal to

M = ((N / p) η _ek -N ₀ / p ₀ ) K, kW / (kg / cm ² ),

where N _o , p _o , N _o1 , p _o1 , N, p are respectively the rated values of power N ₀ and pressure p ₀ when the pump is operated with a closed gate valve, during experimental measurement of pump parameters for a closed gate valve N ₀₁ , p ₀₁ and power and pressure during current pump operation N, p.

Consumption coefficients M _p with known operational coefficients η _ek and K are calculated from equations with passport values of the corresponding coefficients

M _p = ((N ± ΔN / (p ± Δp)) η _ek -N ₀ / p ₀ ) kW / MPa

the convergence coefficient K is equal to

K = M _p / (((N _p ± ΔN) / (p _p ± Δp)) η _ek -N _o / p _o ,

where K, M _r , p and N are taken over the entire range of passport characteristics, based on the calculated values of K and M _r , the K-M _r characteristic is constructed (Fig. 10), the current value of the expenditure coefficient M _r , taking into account the convergence coefficient K, is calculated by the equation or according to the characteristic K-M _p

M = ((N / p) η _ek -N ₀ / p ₀ )) K, kW / (kg / cm ² ),

the calculated value of the flow coefficient M _r according to the flow characteristic MQ calculates the volume flow Q _o :

Q _o = Q _min + (M _p -M _min ) (Q _max -Q _min ) / (M _max -M _min ), volume / time;

or according to the polynomial equation of a graphical dependence of Q on M, for example, for the flow rate characteristic shown in FIG. 4 for a VAT pump 18 or in (FIG. 7) for a VAT pump 14.

, м³/час (18 НДС),

, m ³ / hour (18 VAT),

, м³/час (14 НДС);

, m ³ / hour (14 VAT);

fluid density ρ _p

, кг/м³

kg / m ³

where p is the pressure developed by the pump, MPa;

N _p - design pressure, m

The efficiency of each pump is determined by the formula

, %

%

specific electricity consumption

, кВт·ч/100 т.м,

, kWh / 100 tm,

pump unit vibration level

The flow rate of the pump will be equal to:

, м³/ч.

, m ³ / h.

At a known power on the pump shaft N _{n, the} flow rate Q is

, м³/ч

m ³ / h

where Q is the flow rate, m ³ / h; P _c is the power consumed by the electric motor from the network, kW; N _n - power on the pump shaft, kW;

p is the pressure developed by the pump, MPa;

η _n - pump efficiency,%;

η _el.dv - the efficiency of the electric motor,%.

The system is equipped with a data transmission system, for all controlled parameters, to a control room with a computer containing a database of all controlled parameters, with which all the necessary data are calculated.

Example of calculating the parameters of a pumping unit

The initial data obtained during the measurement period at the pumping unit 18 VAT with a drive from an asynchronous electric motor when operating on water with p = 998 kg / m ³ :

Recalculated performance characteristics of pump No. 6 18 VAT at pump station 2NFS

In the calculation we use table 3 and the graphs given in Figs. 3, 4, 5

Table 3 18NDS Pump Performance Q N N ηн R M m ³ / hour M kw % kg / cm ² kW / (kg / cm ² ) 0 41.63 78.96 0 4,155 0.01 302.9 41.23 105.1 thirty 4,115 6.54 602.14 40.16 127.7 fifty 4.08 12.3 900,4 39.5 145 67 3.94 17.8 1193.1 37.77 157.27 78 3.77 22.71 1487.8 37.07 170 85 3,7 26.94 1773.6 33.86 181.33 90 3.38 34.65 2066.8 31.06 184.6 91 3,1 40.55 2356.1 23.1 188 84 2,724 50,0 2500,1 24.6 194 82 2.45 61.18

Flow characteristic

Q = 0.0001 M ⁴ -0.0258 M ³ +1.1267 M ² +39.012 M + 0.5779

Based on the basic data, we determine the value of the flow coefficient M _{0 of the} constant component of the flow characteristic of the pump when the pump is operating on a closed valve

M ₀ = 78.96 / 4.155 = 19 kW / (kg / cm ² )

We determine the operational coefficient during pump operation during start-up on a closed gate valve at its outlet

Experiment Data

Power N ₀₁ = 78.96 kW

Pressure p ₀₁ = 4.155 kg / cm ²

Consumption coefficient M is equal to

M = ((N / p) η _ek -N ₀ / p ₀ ) K, kW / (kg / cm ² )

The operational coefficient η _eq is

η _ec = (N ₀ / p ₀ ). (p ₀₁ / N ₀₁ )

Parameters during operation:

pump outlet pressure r _o - 2,824 kg / cm ² pump inlet pressure p _I - 0.1 kg / cm ² power measured by the device R - 201.07 kW Motor efficiency η _ed - 93.5% bearing temperature T _p - 80 ° C pump housing temperature T _to - 60 ° C

Payment

Power on the motor shaft N _ed = 201.07 · 0.935 = 188 kW

Power on the pump shaft N _n = 188 kW

The pump pressure p _O p _in = 2,824-0,1 = 2,724 kg / cm ²

Consumption coefficient M is equal to

M = (N / p) η _ek -N ₀ / p ₀ ) K = ((188 / 2,724) 1-19) 1 = 50.0 kW / (kg / cm ² )

The flow rate Q at η _ec = 1 and K = 1 will be equal to

Q = 0.0001 M ⁴ -0.0258 M ³ +1.1267 M ² +39.012 M + 0.5779

Q = 0.0001 50 ⁴ -0.0258 50 ³ +1.1267 50 ² +39.012 50 + 0.5779 = 2368 m ³ / hour

The data in the table Q = 2356.1 m ³ / hour

The difference in the calculation is 0.5%.

If the operational coefficient is not equal to unity

η _ek ≠ 1, then we determine the deviation of power and pressure from the certified values and calculate the expenditure coefficient M _p and the coefficient of convergence K over the entire range of characteristics.

Calculation of the pump 14 VAT for one flow

In the calculation we use table 4 and the graphs shown in Fig.6, 7, 8, 9, 10

Table 4 Recalculated pump performance 14 VAT Operating Recalculated Pump Characteristics 14 VAT 1 M ₀ = N ₀ / p ₀ = 145.77 / 9.05 = 16.107 Q m ³ / day N m N kW p kg / cm ² Efficiency% M kW / (kg / cm ² ) 0 91.06 145.77 9.05 0 0 226.84 91.06 176.69 9.05 thirty 3.41 453.3 91.06 213.21 9.05 54 7.45 679 91.06 237.84 9.05 65 10.17 905 87.06 268.55 8.61 76.5 15.08 1130 85.79 296 8.56 83.5 18.47 1354.73 81.73 325.92 8.15 89 23.88 1578.93 75.52 350.11 7.54 88.5 30.32 1800.8 71,4 384.5 7.12 87 37.9 2023.86 66.07 416.22 6.59 82 47.05 2135.9 59.27 421.77 5.9 80 55.38

Determination of the parameters of pump No. 6 14 VAT at the pump room, 2NFS when starting the pump on a closed gate valve

Experimental data:

electricity I ₀₁ - 17.5 A pump inlet pressure p _{in o1} - 0 pump outlet pressure _{out 01} - 6 kg / cm ² mains voltage U ₀₁ - 6 kV Cosφ electric motor Cosφ ₀₁ - 0.9 Motor efficiency η _ed01 - 0.92

Basic values when starting the pump on a closed gate valve

power N ₀ - 145.77 kW pump pressure p ₀ - 9.05 kg / cm ²

We calculate the operational coefficient η _ek

η _ec = (N ₀ / p ₀ ) (p ₀₁ / N ₀₁ )

p ₀₁ = p _{out 01-} p _{in o1} = 6-0 = 6 kg / cm ²

N ₀₁ = √3U ₀₁ I ₀₁ Cosφ ₀₁ η _{ed 01}

N ₀₁ = 1.73 6 17.5 0.9 0.92 = 150.4 kW

η _ek = (145.77 / 9.05) (6 / 150.4) = 0.643

Deviations from the passport values:

power ΔN = 150.4-145.77 = 4.63 kW,

pressure Δp = 6-9,05 = -3,05 kg / cm ²

We calculate the coefficient of convergence K

We take from the table the basic value of the flow, equal to

Q = 2135.9 m ³ / h, while M = 55.38, p = 5.9 kg / cm ² , N = 421.77 kW.

Then K is equal

K = M / (((N + ΔN / (p-Δр)) η _ek -N ₀ / p ₀ )

K = 55.38 / (((421.77 + 4.63) / (5.9-3.05)) 0.643-16.107) = 0.69

We calculate the expenditure coefficient M from the available data for N and p.

N = 384.5 kW, p = 7.12 kg / cm ² ,

M = (((N / p) +4.63)) / (p-3.05)) 0.643-16.107) K

M = ((((384.5 + 4.63) / (7.12-3.05)) 0.643-16.107) 0.69 = 39.2 kW / kg / cm ²

Consumption is calculated by the formula:

Q = 9E-05 M ⁴ -0.0076 M ³ -0.4059 M ² +69.522 M-6.27

Q = 9E-05 · 39.2 ⁴ -0.0076 · 39.2 ³ -0.4059 · 39.2 ² + 69.522 · 39.2 = 1849.73 m ³ / h

The difference is 1849.73-1800.8 = 48.93 m ³ / hour or 2.7%

We will calculate for the pump 14 VAT in the entire range of characteristics using table 5.

Table 5 Pump parameters 14 VAT Q m ³ / hour N kW p, kg / cm ² M, kW / kg / cm ² N, kW ± ΔN = N _p + ΔN = 4.63 p, kg / cm ² ± Δp = p _p Δp = -3.05 M _p = (N _p / p _p ) × η _ek - (N ₀ / p ₀ ) η _ek = 0.643 N ₀ / p ₀ = 16.107 Coef. gathering. TO M = K Mr 0 145.77 9.05 0 145.77 + 4.63 9.05-3.05 0 one 0 226.4 176.89 9.05 3.41 176.89 + 4.63 9.05-3.05 3.35 1,0179 3.47 453.3 213.21 9.05 7.45 213.21 + 4.63 9.05-3.05 6.74 1.105 7.45 679 237.84 9.05 10.17 237.84 + 4.63 9.05-3.05 9,878 1,0295 10.17 905 268.55 8.61 15.08 268.25 + 4.63 8.61-3.05 15.45 0.976 15.08 1130 296 8.56 18.47 296 + 4.63 8.56-3.05 18,976 0.973 18.47 1354.73 325.92 8.15 23.88 325.92 + 4.63 8.15-3.05 25,568 0.934 23.88 1578.93 350.11 7.54 30.32 350.11 + 4.63 7.54-3.05 34,694 0.874 30.32 1800.8 384.5 7.12 37.9 384.5 + 4.63 7.12-3.05 45.37 0.835 37.9 2023.86 416.22 6.59 47.05 416.22 + 4.63 6.59-3.05 60.33 0.78 47.05 2135.9 431.77 5.9 55.38 421.77 + 4.63 5.9-3.05 80.09 0.69 55.38

The sequence of calculation. Pump 14 VAT

The calculation of the pump parameters can be done in two ways.

We calculate from the passport data the value of the flow coefficient M ₀ at zero flow at the beginning of the operating characteristics

M ₀ = N ₀ / p ₀ = 145.77 / 9.05 = 16.107 kW / (kg / cm ² )

We calculate the operational coefficient η _ek

η _ec = (N _o / p _o ) (p _o1 / N ₀₁ ) = 16.107.6 / 150.4 = 0.643,

where N ₀ , p ₀ , N ₀₁ , p ₀₁ - respectively, the power and pressure taken from the passport characteristic of the pump, and the power and pressure obtained when the pump was operated with a closed valve.

We determine the deviation of power and pressure from the nominal values in the entire range of characteristics

ΔN = N ₀ -N ₀₁ kW, Δp = p ₀ -p ₀₁ , kg / cm ²

The resulting deviations in power and pressure are added over the entire range to the pump performance.

We calculate in the entire range according to the passport data the estimated expenditure coefficient M _p , with the coefficient of convergence K = 1, according to the formula

M _p = ((N ± ΔN / (p ± Δp)) η _ek -N ₀ / p ₀ ),

and from the calculated M _p and the certified value of M, we calculate the convergence coefficient K = M / M _p

We build graphs of the dependence of the passport expenditure coefficient M on the estimated expenditure coefficient M = f (M _p ) and K = f (M _p ) or calculate by the formula K = M / M _p

In the process of measurement, the calculated expenditure coefficient M _{p is} calculated by the formula

M _p = (N / p) η _ek -N ₀ / p ₀ ), and according to the calculated value of M _p

by the characteristic M = f (M _p ) (Fig. 9), or by the formula

M = (N / p) η _ek -N ₀ / p ₀ ) K

The actual flow coefficient M, according to the schedule Q = f (M) (Fig. 7), the volumetric flow rate Q ₀ m ³ / h is determined.

Below are the calculation formulas for calculating the required values obtained from the above graphs.

Settlement formulas:

Q = 9E-05 M ⁴ -0.0076 M ³ -0.4059 M ² +69.522 M-6.27 m ³ / hour

M = ((N / p) η _eq -16.107) K

M _p = (((N ± ΔN) / (p ± Δp)) η _ek -16,107) K, where K = 1

η _ec = (N ₀ / p ₀ ). (p ₀₁ / N ₀₁ )

N ₀ -N ₀₁ = ± ΔN, r _about -p _o1 = ± Δp

K = 55.38 / ((N + ΔN / (p-Δp)) η _ek -16.107

K = 55.38 / ((421.77 + ΔN) / (5.9-Δp)) η _ek -16.107

The convergence coefficient in the limit of the operating range of the pump varies slightly and amounts to 1.5%. The difference in K also depends on the accuracy of recalculation of the nameplate characteristic of the pump.

Functional diagram of the automation of one pump is given in Fig.11.

On Fig shows the experimental graphs for measuring the flow rate of water for two days, supplied by pumps 14 NDS and 18 VAT at the pumping station 2NFS "Samaravodokanal" with an additional measurement of the available water flow meter.

On Fig shows the experimental graphs for measuring the flow rate of water for two days supplied by the pumps 14 VAT and 18 VAT at the pumping station 2 of the NFS Samaravodokanal.

On these characteristics there are designations: 1 - characteristics of one working pump 18 VAT; 2 and 3 - characteristics of two parallel-running pumps 14 VAT and 18 VAT; 4 - total consumption during operation of two pumps 14 VAT and 18 VAT; 5 is a flow characteristic of an ultrasonic flow meter.

The automated information system under consideration for measuring and analyzing in real time the main performance indicators of pumping stations with centrifugal electric pumps in water supply and sanitation systems conducts a continuous analysis of the operation of pumping equipment at pumping stations. These data carry information on flow rate, pressure, power temperature, efficiency, specific energy consumption, mean time between failures, which are given in the form of graphs and tables for analysis and decision-making on maintaining optimal operating conditions of the pumping station. Currently, this system operates at one Samaravodokanal pumping station. It is planned to introduce this system at all pumping stations that are connected to a central control center.

Information sources

1. Patent 2119148 of the Russian Federation. A method of measuring the mass flow rate and density of a fluid 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 measuring and analyzing in real time the main performance indicators of pumping stations with centrifugal electric pumps in water supply and sanitation systems, containing pumping stations with pressure sensors and power sensors, characterized in that it is equipped with temperature sensors in addition to pressure sensors and power sensors , for measuring the temperature of the bearings and the pump housing and a sensor for measuring the vibration of the pumping unit, data transmission system, volume connecting the outputs of all sensors and messages with an information center containing a computer and a database of measured parameters, using which the power acting on the shaft of each pump N is calculated taking into account the drive of the pump from the synchronous motor of the asynchronous motor, by multiplying the power consumed from the network P _with efficiency of the motor η _ed calculated pressure generated by pump p, by subtracting the output pressure of the pump p _O, the pressure p at the input _Rin, calculated on the passport data of Achen consumable coefficient M ₀ at zero flow at the beginning of the performance, by dividing the power N ₀ on the pressure p _0, the experimentally determined service factor η _eq of the pump of the closed valve, by multiplying the power dividing the product N _o at pressure p _o, at work pump at the closed valve, taken from the pump performance, the result of dividing the measured pressure values p _o1 on the measured power of the pump shaft N _o1, on operational coefficient η _eq determined rejected power ± ΔN and pressure ± Δр, from the nominal values and in the entire range of rating characteristics, the resulting deviations in power and pressure are added to the pump performance in terms of power N ± ΔN and pressure p ± Δр, calculated over the entire range from the rating data coefficient M _p , without the coefficient of convergence K, by multiplying the result of dividing the power N ± ΔN by the pressure value p ± Δp, by the operating coefficient η _ek , minus the value of the consumption coefficient M ₀ , a dependency chart is built of the flow coefficient M from the calculated M _{p of the} expenditure coefficient M = f (M _p ), during the measurement period, the calculated value of M _p by the characteristic M = f (M _p ) determines the actual expenditure coefficient M, and according to the schedule Q = f (M ), the volumetric flow rate 0 is determined when determining the flow rate using the convergence coefficient K, which is determined over the entire range of characteristics, by dividing the passport flow coefficient M by the estimated flow coefficient M _p , and the graphs K = f (M _p ) or K = M are constructed / Mr, the found value of K is calculated the flow coefficient M by the formula, by dividing the convergence coefficient K by the calculated flow coefficient M _p , the volume flow rate Q is calculated from the calculated flow coefficient by the flow characteristic Q = f (M), and the flow rate is calculated using the calculated pressure characteristic HQ , and according to it the density p of the pumped liquid by dividing the effective pressure created by the pump by the effective design pressure H and the coefficient g, the pump efficiency is calculated by multiplying I pressure on the result of dividing the flow rate by the power, the specific energy consumption W _beats , by dividing the density by the efficiency of the pump and electric motor with the corresponding coefficients, the temperature on the pump bearings and the temperature of the pump casing are measured by instruments, and the vibration amplitude is measured by the sensor measuring vibration, the calculated data on the transmission system are sent to the control room in a computer containing the appropriate database, with the help of which all the necessary information is calculated stations for measuring and analyzing in real time the main performance indicators of pumping stations.

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