CN105512948A - Automatic water quantity measuring method of small-scale pumping station - Google Patents

Abstract

The invention relates to an automatic water quantity measuring method of a small-scale pumping station and belongs to the water-saving irrigation technical field. A pressure detection device for measuring pressure is installed on the water outgoing pipeline of a water pump; a distance from the water surface of the water source of the pumping station to the center line of the water outgoing pipe of the pumping station is detected; and a pumping station flow rate calculation formula can be derived through using a Bernoulli equation, a water quantity continuous equation and a water pump performance curve. With the measuring method adopted, a small-scale water pump measuring device and a controller can be developed. The measuring method can be applicable to water quantity measurement of pumping stations of different models in different occasions. The automatic water quantity measuring method has the advantages of low cost, simple device, convenient operation and accurate measurement, and can be applied to and popularized in small-scale pumping stations.

Description

A kind of automatic water gauge metering method of small pumping station

Technical field

The present invention relates to a kind of automatic water gauge metering method of small pumping station, belong to water-saving irrigation technique field.

Background technology

Agricultural irrigation water accounts for more than 60% of total Water, measures agricultural irrigation water, by side's charge, very important meaning is had to propelling agricultural water-saving irrigation, at present, adopt existing pumping plant measuring apparatus (equipment) cost higher, be difficult to spread.

Patent content

Object of the present invention is exactly the deficiency existed for existing water consumption measurement technology, according to the energy Bernoulli equation of water pump intake-outlet, water yield continuity equation and characteristic curve of pump, provides a kind of automatic water gauge metering method of small pumping station.

The object of the present invention is achieved like this, a kind of automatic water gauge metering method of small pumping station, it is characterized in that, first measure water pump water outlet pipe pressure, then the distance of the pumping plant intake pool water surface to pumping plant rising pipe central datum line is detected, finally utilize Bernoulli Jacob's energy equation, water yield continuity equation and characteristic curve of pump, derive pumping plant flow rate calculation formula;

Wherein, with water inlet 1-1 section to rising pipe 2-2 section, Bernoulli Jacob's energy equation is set up:

$\frac{p_1}{\mathrm{\ρ}}+\frac{v_1^2}{2g}-h_1=\frac{v_2^2}{2g}+\frac{p_2}{\mathrm{\ρ}}+h_f-H_t---\left(1\right)$

In formula, p ₁for the pressure of water inlet 1-1 section, its value is zero;

ρ is 1.0;

V ₁, v ₂be respectively water inlet 1-1 and rising pipe 2-2 section water velocity;

P ₂for rising pipe 2-2 cross-section pressure meter reading;

H ₁for the pumping plant intake pool water surface is to the distance of pumping plant rising pipe center line;

H _ffor the loss of flood peak;

H _tfor pump head;

Set up water yield continuity equation:

A ₁v ₁＝A ₂v ₂＝Q(2)

In formula, A ₁for water inlet 1-11 cross-sectional area;

A ₂for rising pipe 2-2 cross-sectional area;

Q is ducted flow;

Set up pump characteristic equations:

H _t＝aQ ²+bQ+c(3)

In formula, a, b, c are coefficient, can draw according to characteristic curve of pump;

By equation (1), (2) and (3) can derive pumping plant flow and water level, pressure relation as follows:

$Q=\frac{-b+\sqrt{b^2-4(a+\frac{1}{2{\mathrm{gA}}_1^2}-\frac{1}{2{\mathrm{gA}}_2^2})(c-p_2-h_f-h_1)}}{2(a+\frac{1}{2{\mathrm{gA}}_1^2}-\frac{1}{2{\mathrm{gA}}_2^2})}---\left(4\right)$

Record h ₁and p ₂just can calculate pumping plant flow, thus obtain the pump-out of pumping plant.

Described water pump water outlet pipe pressure is measured by the pressure-detecting device be installed on pumping line, and described pressure-detecting device is tensimeter.

The advanced science of the inventive method, by method provided by the invention, a kind of small pumping station water consumption measurement method, mainly installs a pressure-detecting device and measures pressure, then detect the distance of pumping plant source water face to pumping plant rising pipe center line on pump outlet pipeline.Utilize Bernoulli Jacob's energy equation, water yield continuity equation and characteristic curve of pump, derive pumping plant flow rate calculation formula.And develop water pump flowmeter with this.Researched and developed by this metering method, can realize the accurate measurement of small pumping station pump-out, save agricultural irrigation water amount.

Main detected parameters has: pump outlet pipeline hydraulic pressure (P ₂); Intakes of pumping station water level is to the distance (h of pumping plant rising pipe center line ₁).

Whole system is by the tensimeter with communication function, water level detecting and communication and be with the computing unit etc. of CPU module, memory module and communication module to form.

In this approach, the hardware unit of exploitation is simple, cost is low, computing formula logicality strong, and metering is accurately, easy to operate.Water yield cheek formula in described method, can adapt to the water consumption measurement of different occasion, dissimilar irrigation lift pumping station (mixed-flow pump, centrifugal pump, axial flow pump, diving pump station etc.).Small-sized irrigation pumping station One's name is legion, measuring apparatus cost is in the past high, is difficult to spread.The related device of small pumping station metering method of the present invention and exploitation, is only about 1/10th of existing similar metering outfit, can spread.

Accompanying drawing explanation

Fig. 1 is pumping for water pump principle schematic.

Embodiment:

Install a tensimeter at pumping plant effluent pipe mouth, at water source, water level device is measured in installing, measures water pump water outlet pipe pressure and the pumping plant water source water surface (the intake pool water surface) distance two parameters to pumping plant rising pipe central datum line;

With water inlet 1-1 section to rising pipe 2-2 section, set up Bernoulli Jacob's energy equation:

$\frac{p_1}{\mathrm{\ρ}}+\frac{v_1^2}{2g}-h_1=\frac{v_2^2}{2g}+\frac{p_2}{\mathrm{\ρ}}+h_f-H_t---\left(1\right)$

In formula, p ₁for the pressure of water inlet 1-1 section, its value is zero;

ρ is 1.0;

V ₁, v ₂be respectively water inlet 1-1 and rising pipe 2-2 section water velocity;

P ₂for rising pipe 2-2 cross-section pressure meter reading;

H ₁for the pumping plant intake pool water surface is to the distance of pumping plant rising pipe center line;

H _ffor the loss of flood peak;

H _tfor pump head;

Set up water yield continuity equation:

A ₁v ₁＝A ₂v ₂＝Q(2)

In formula, A ₁for water inlet 1-11 cross-sectional area;

A ₂for rising pipe 2-2 cross-sectional area;

Q is ducted flow;

Set up pump characteristic equations:

H _t＝aQ ²+bQ+c(3)

In formula, a, b, c are coefficient, can draw according to characteristic curve of pump;

By equation (1), (2) and (3) can derive pumping plant flow and water level, pressure relation as follows:

$Q=\frac{-b+\sqrt{b^2-4(a+\frac{1}{2{\mathrm{gA}}_1^2}-\frac{1}{2{\mathrm{gA}}_2^2})(c-p_2-h_f-h_1)}}{2(a+\frac{1}{2{\mathrm{gA}}_1^2}-\frac{1}{2{\mathrm{gA}}_2^2})}---\left(4\right)$

Record h ₁and p ₂just can calculate pumping plant flow, thus obtain the pump-out of pumping plant, can pump capacity be calculated.Method and system structure is simple, and cost is low, and implement easily, metering is reliable.

Claims (2)

1. the automatic water gauge metering method of a small pumping station, it is characterized in that, first measure water pump water outlet pipe pressure, then the distance of the pumping plant intake pool water surface to pumping plant rising pipe central datum line is detected, finally utilize Bernoulli Jacob's energy equation, water yield continuity equation and characteristic curve of pump, derive pumping plant flow rate calculation formula;

Wherein, with water inlet 1-1 section to rising pipe 2-2 section, Bernoulli Jacob's energy equation is set up:

$\frac{p_1}{\mathrm{\ρ}}+\frac{v_1^2}{2g}-h_1=\frac{v_2^2}{2g}+\frac{p_2}{\mathrm{\ρ}}+h_f-H_t---\left(1\right)$

In formula, p ₁for the pressure of water inlet 1-1 section, its value is zero;

ρ is 1.0;

V ₁, v ₂be respectively water inlet 1-1 and rising pipe 2-2 section water velocity;

P ₂for rising pipe 2-2 cross-section pressure meter reading;

H ₁for the pumping plant intake pool water surface is to the distance of pumping plant rising pipe center line;

H _ffor the loss of flood peak;

H _tfor pump head;

Set up water yield continuity equation:

A ₁v ₁＝A ₂v ₂＝Q(2)

In formula, A ₁for water inlet 1-11 cross-sectional area;

A ₂for rising pipe 2-2 cross-sectional area;

Q is ducted flow;

Set up pump characteristic equations:

H _t＝aQ ²+bQ+c(3)

In formula, a, b, c are coefficient, can draw according to characteristic curve of pump;

By equation (1), (2) and (3) can derive pumping plant flow and water level, pressure relation as follows:

$Q=\frac{-b+\sqrt{b^2-4(a+\frac{1}{2{\mathrm{gA}}_1^2}-\frac{1}{2{\mathrm{gA}}_2^2})(c-p_2-h_f-h_1)}}{2(a+\frac{1}{2{\mathrm{gA}}_1^2}-\frac{1}{2{\mathrm{gA}}_2^2})}---\left(4\right)$

Record h ₁and p ₂just can calculate pumping plant flow, thus obtain the pump-out of pumping plant.

2. the automatic water gauge metering method of a kind of small pumping station according to claim 1, is characterized in that, described water pump water outlet pipe pressure is measured by the pressure-detecting device be installed on pumping line, and described pressure-detecting device is tensimeter.