JPS5956516A - Method for adjusting flow rate of cooling water - Google Patents

Abstract

PURPOSE:To optimize the flow rate of feed water and to economize driving power consumtion by changing the number of revolutions of a feed water pump which supplies cooling water in compliance with the temp. of feed water and controlling the flow rate of the water in accordance with the change in the temp. CONSTITUTION:A titled method consists of a stage for detecting the temp. and pressure for feed water, a stage for calculating the pressure of the feed water from the temp. signal thereof by a calculator 20 for determining pressure, a stage for inputting the calculated pressure signal of the feed water and the above-mentioned detection signal for the pressure of the feed water to a pressure controller 28 and calculating the pressure deviation between both and a stage for controlling the number of revolutions of a feed water pump 4. The detection of the above-described temp. and pressure is accomplished by a water temp. detector 18 and a water pressure detector 22 provided on the discharge side of the pump 4. The flow rate of feed water is optimized by the above-mentioned method and driving power consumption is economized.

Description

[Detailed Description of the Invention] 4. The invention relates to a cooling water flow h1 adjustment method, and! This invention relates to a method that can reduce the power consumption of water pumps.

Generally, a huge amount of cooling water is used in a manufacturing factory. As an example of a conventional cooling water supply system, a steel rolling mill shown in Fig. 1 will be explained. The water in the water tank 2 is pressurized by the water pump 4, passes through the water pipe 6, and then is connected to automatic water 114 valve 8 or manual water! Water is supplied to the cooler 12 through a control valve 10, and a return pipe 14. Cooling tower 16'! circulating through i-.

Conventionally, such cooling water supply systems have had the following problems.

(a) When the amount of water supplied decreases, the pressure at the pump outlet increases unnecessarily, resulting in wasted energy. As shown in the pump characteristic diagram of FIG. 6, which will be described later, the water supply pressure increases due to the decrease in the amount of water supply, and the electric power cost per unit of stored water increases.

(b) When the water supply temperature decreases, the required amount of water supply decreases. The water supply amount and water pressure of the cooling water supply system are adjusted based on the highest water supply temperature in the summer, so
In seasons other than summer, the water supply temperature is low, so the truly necessary water supply i is less than this cutoff value, and the truly necessary water supply pressure also decreases as the amount of water supply decreases. Therefore, the pressure at the pump outlet tends to fluctuate unnecessarily except in summer.

Generally, a steelworks has a large number of various heating furnaces including blast furnaces and converters, and each device is equipped with a cooling water supply system as shown in Figure 1 to protect these devices from heat.

Each device is equipped with cooling piping and valves,
1m long with an infinite number of valves! 8- It is not possible to finely adjust the amount of water due to changes, and cooling water is often used at a constant valve opening for five years.

Depending on the equipment, a flow control valve may be installed to adjust the flow rate, or the flow rate may be adjusted manually by opening and closing the valve [7]
However, when looking at the entire factory, it cannot be said that the flow rate of the cooling water supply system is managed properly.

The object of the present invention is to solve the problems of the prior art described above.

We provide a complete method for adjusting the flow rate of cooling water that automatically adjusts the flow rate according to the temperature of the water supply.

The gist of the present invention is as follows.

In other words, in the flow rate adjustment method suitable for the supplied cooling water temperature, there are two steps: detecting the temperature and pressure of the water supply using a water temperature detector and a water pressure detector installed on the discharge side of the water supply pump, and (7) Feed water temperature U (>``'') is the pressure controller, and the firefly calculates the pressure deviation ′(
and a step of receiving the pressure deviation signal to a rotation speed control device to control the rotation speed of the water supply pump. This is a cooling water departure adjustment method based on the % characteristic.

The details of the present invention will be explained with reference to examples and drawings thereof. Second
17 is a diagram of the cooling water supply system of the present invention in which an automatic adjustment function is newly added to the conventional cooling water supply system shown in FIG. The water temperature detector 18 installed in the water supply pipe 6 detects the hidden water supply, and the necessary water supply pressure P? is calculated by the pressure calculation unit 20 from the following equation (1).

Just 1. P: Water supply pressure (kg/crl) te: Water supply temperature (cooling water temperature) (℃) PO: Minimum required water supply pressure (℃) K hm: Pressure loss of the entire water supply system at the maximum water supply temperature of m cooler (ky , /cJ) Q: Heat removal rate of the m cooler (Kcal/h) qm: Water supply interval at the maximum water supply temperature of the m cooler (kg/hl) Te: Cooler inlet temperature of the object to be cooled in the m cooler ( ℃
) Td:m Cooler outlet temperature of the object to be cooled in the cooler (°C
) Heat transfer surface P* of the Arm cooler This is the cooler that requires the highest water supply pressure.

On the other hand, the water pressure detector 22M installed in the water supply pipe 6 at the discharge (111) of the water supply pump 4 detects the water supply pressure [7, Performance 1!
The total pressure controller 24 calculates the pressure deviation of El, water supply pressure, etc., and this pressure deviation signal is converted by the rotation speed control device 26. The number of revolutions of the motor 28 of the water supply pump 4 is controlled. Thus, as shown in the third ash.

Supply water temperature π suitable 1. The water supply pump'4) can be turned around depending on the pump rotation speed and discharge pressure.

Example 2 In a steel rolling factory with a cooling water supply system shown in Fig. 2f, the temperature and pressure of the water supply were detected using the method π of the present invention, and the rotational speed of the water pump was controlled to adjust the cooling water. The specifications of the system are as follows.

Maximum water supply temperature: 32℃ Maximum discharge rate of water supply pump: 1450 d/h Maximum head of water supply pump: 42m Number of coolers: 36 units 13 units of coolers have an automatic control valve to automatically adjust wrinkles in the cooling water However, the remaining 23 cold 7AL units took into consideration the effect of 1. It does not have an automatic control valve.

The results of this example are shown in the diagrams of Figures 4-8.

It has an automatic adjustment function based on the temperature of the cooling water supply (shown in comparison with a conventional example).

Line A shows the embodiment of the present invention, and line Y3 shows the conventional examples 1-5.

Figure 4 shows the relationship between the water supply temperature and the water supply amount.1 The difference in the water supply amount between the example of the present invention and the conventional example is the difference in the cooler pressure without using the automatic control valve k'4. This is also due to the fact that excess cooling water did not flow due to the application l effect.

FIG. 5 shows the relationship between the water supply temperature and the pump power consumption. On the low temperature side, the pump power consumption of the example of the present invention is equal to
It can be seen that the automatic control of the present invention is highly effective.

FIG. 6 shows the relationship between the water supply temperature and the pump discharge pressure, that is, the water supply pressure, and the example of the present invention in which the pressure is changed depending on the temperature of the water supply has a significantly lower pressure than the conventional example.

Figure 7 shows all the monthly average seasonal trends in water supply temperature.

Figure 8 shows the trends in monthly average pump power requirements.
Example of the present invention) Consumption type, power V is 9 on average for 17 years compared to conventional example
5 KW '9・Reduction of 1-% shows that the effect is remarkable in the cold season.

As is clear from the present invention &-',,t,',%'2 Examples, in the amount of cooling water supplied (i'1), the rotation In of the water supply pump is changed depending on the temperature of the water supply, and the water supply ratio is adjusted. By doing so, we were able to significantly reduce the power consumption of the water pump.

It goes without saying that the method of the present invention can be widely applied to cooling other than steel factories, but can also be widely applied to iron manufacturing related equipment as described below.

(b) Roll cooling water for rolling mills (b) Cooling water for hot rolling mills (c) Cooling water for the following departments that uses seawater for the entire time stave cooling water

[Brief explanation of drawings]

Figure 1 is a conventional cooling water supply system diagram, Figure 2 is a cooling water supply system diagram of the present invention, and Figure 3 is a diagram showing the relationship between the water supply gA degree, the water pump rotation speed, and the water pump discharge pressure of the present invention. ,
Figure 4 is a line showing the relationship between feed water temperature and water supply amount, and Figure 5 is a line showing the relationship between feed water temperature and pump power consumption.Figure 1-6 is a line showing the relationship between feed water temperature and pump discharge force. Figure 7 is a diagram showing changes in annual water supply m[, and Figure 8 is a diagram showing changes in monthly average pump power consumption over the year. 4... Water supply pump, 6... Water supply pipe. 12...Cooler, 18...Water temperature detector. 20...Pressure determination calculator, 22...Water pressure detector, 2
4... Pressure controller, 26... Rotation speed control device. Agent Takeo Nakaji ψ 111! ! ", 0- ) Go 4 Misakibato

Claims (1)

[Claims] (1) A flow meter adjustment method suitable for the supplied cooling water temperature, which includes the steps of: detecting the temperature and pressure of the water supply using a water temperature detector and a water IE detector provided on the discharge side of the water supply pump; The m open signal is sent to the pressure determining calculator, which calculates the water supply pressure suitable for the water supply temperature, and the detected water supply pressure signal and the calculated water supply pressure A are converted to a pressure of 1 tNI.
The pressure difference between the two is J) Ill stage;
^ [(The stage where the distribution pressure deviation signal is sent to the rotational speed control device is the stage that controls the rotating sand of the front Ae water supply pump] What is the difference between 1° and 1°? Characteristics - Cooling water flow h1 adjustment method θ mi .