JPS5946497A - Outlet temperature controlling system for cooling water of water cooling tower - Google Patents

Abstract

PURPOSE:To automatically control the outlet temperature of cooling water positively, by detecting the average temperature on the surface of water in the cooling water pit of a water cooling tower, and by automatically changing the number of revolution of a cooling fan, based on the detected signals of the average temperature. CONSTITUTION:The air flow rate of a cooling fan is controlled by detecting the average temperature in the surface part of water in a cooling water pit, where the change in temperature in cooling water can be detected fastest by a temperature detecting means 14, and by putting the detected value into a temperature controller unit 11 as a feedback signal, and then by automatically changing the number of revolution of a cooling fan 3 in accordance with a deviation signal. By this means, the change in temperature in cooling water can be detected with little time lag being produced, even in the case of a cooling water system in which fluctuation in temperature and the flow rate of return water are large, and the temperature at the outlet of cooling water can be automatically controlled positively, by controlling the number of revolution of a cooling fan smoothly without producing the hunting action.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling water system having at least one cooling water tower basin and distributing cooling water between the cooling tower and the process.
This invention relates to a system for automatically controlling the cooling water output temperature of a cooling tower to a management target temperature required by the process side.

The conventional cooling water outlet temperature + 1 + II control system with this value will be explained with reference to Fig. 1. 1 is a cooling water tower, 2'
t 2b is the cooling water outlet piping and cooling water return distribution B for circulating cooling water between the cooling tower 1 and the process (Igl not shown), and 3 is the cooling installed on the convex IS of the chilled water tower 1. A fan, 4 is its drive motor, 5 is a cooling air intake loop, 6 is a cooling water pit provided at the bottom width 5 of the cold water heater 1, which communicates with the cooling water outlet mark α2a. .

As the cooling water tower 1, a circulation type cooling water tower as shown in FIG. 2a or a direct-flow type cooling water tower as shown in the second section 1b can be used. 7 is a sprinkler pipe connected to the cooling water return pipe 2b;
Reference numeral 8 designates a filling/proboscis provided below the water spray pipe 7, and 9 designates an eliminator. IO is a delivery bonder inserted in the cooling water outlet mark #2a, which is used to circulate the cooling water. Then, the low-temperature cooling water 13 in the cooling water pit 6 is pumped out through the delivery bonder and distributed to the process to cool the process, and the heated cooling water is returned and distributed.
After b, water is sprayed - Return to #7, water is sprayed - Cooling water is sprayed from #7 and passes through the filling port 8 t1 Cooling fan 3 seals -
The cooling air flow sucked into the interior of the pipe 5 and discharged to the outside through the charger 8 and the eliminator 9 causes the cooling water to be returned to the pit 6 and circulated.

In order to automatically TFF control the cooling water outlet temperature to the management target temperature, the conventional system detects the cooling water temperature on the suction side or the discharge side (cooling water outlet piping 2a) of the delivery pump 10,
The cooling water temperature detection signal is input to the temperature adjustment needle unit 11 and compared with the temperature setting signal (signal set to the management target rm degree required by the process side), and the rotation speed is controlled according to the deviation signal. The unit 12 automatically changes the rotational speed of the cooling fan g-motor 4 and the cooling fan 3. That is, when the detection signal is larger than the setting signal, the rotation speed of the cooling fan drive motor 4 and the cooling fan 3 is increased, and when the detection signal is smaller than the setting signal, the rotation speed of the cooling fan drive motor 4 and the cooling fan 3 is increased. The rotation speed of the automatic type 1 is reduced to make the deviation signal zero, and the air volume of the cold 417 An 3 is increased or decreased to bring the cooling water outlet temperature to the management target temperature.
I have something to control.

However, in such conventional systems, since the cooling water outlet temperature is detected, in the case of a cooling water tank where the return water temperature or water volume fluctuates greatly, the water expansion bit 6 is used to detect changes in the cold water temperature. As a result of the time delay in dissolving the retained water in the cooling water pit 6, the control of the coating layer (fan 30 rotation speed 1) will be greatly disturbed (hunting).The source of this hunting is that the retained water in the cooling water pit 6 is large. If the size is too large, there is a drawback that the cooling water outlet temperature cannot be automatically controlled.

The present invention is aimed at improving the above-mentioned drawbacks, and the detection point is selected as the detection point immediately below the water surface of the cold water bit, where changes in cooling water temperature can be detected earliest, and the average temperature of the water surface Ii
f,? ! - Even in the case of a cooling water system with large fluctuations in water temperature and water volume, changes in cooling water temperature can be detected with almost no time delay, and cooling fan rotation speed can be detected by hunting. I've made it possible for you to wholesale 1 Jjh city 1 ha without causing any trouble and to be able to wholesale cold meat 11 cold water rkw all the way.

The system of the present invention will be explained below with reference to the drawings.

In the present invention, the detection point is selected as the detection point immediately below the water surface of the cooling water pit 6, where changes in cooling water temperature can be detected earliest.

The reason for detecting average rM ) i k is that even within the same chilled water 41, the cooling effect partially differs depending on the shape of the filling 8, the direction of the gas and liquid wind, the type of the cooling tower 1, etc.
This is because the warm dead bodies on the water surface are partially different. For example, if looper 5 (cooling air intake) is installed on the east and west sides of cold water 41, if the wind direction is east wind, then the east light side 'l'
'/ The cooling water sprinkled over 18 districts is better for drinking. In addition, in the case of a countercurrent type cold water tank as shown in Figure 2a, filling,
The wind speed of the cooling air passing through the Il/I8 tray is faster at the center and slower toward the outside, so the center of the filling 8 is moderately cooled, and the cooling water flowing through the tray is well distributed. In addition, in the case of a cross-flow cooling water tower as shown in Fig. 2, as the cold air passes through the filling's nose 8 from the outside to the inside, the air rises. The outer part of the cut 8 is moderately cool, and the cooling water that passes through the cut 1 is well cooled. If the cooling effect is partially different in this way, the temperature of the water in the cooling water pit 6 will be partially different, and once the difference has passed, it will be stirred and convected over time, and the temperature of the water in the cooling water pit 6 will be equalized by stirring and convection. However, since there is a time delay, the temperature detection point for the water amount is set at one location, and the water temperature is
This is because if the average VAj standard of the river is not detected, as mentioned above, the rotation speed control of the cooling fan 3 may not be performed smoothly due to the hunting mechanism, and there is a risk that the cooling water outlet temperature may not be determined in an intransitive manner. .

As the average temperature detection means 14! As shown in Figure 4S1, temperature detection elements 14a to 1 such as thermocouples and resistance temperature detectors are arranged at multiple detection points to detect the average temperature of the water stream.
40 and a temperature averaging processing unit (14t) which averages the temperature detected by these temperature detection elements 14a to 140 and uses it as an average temperature detection means, or as shown in FIG. Multiple temperature detection elements 14a
~14 (A device in which L is connected in series, in parallel, or in series and parallel, or a combination of these can be used. Because of the detection points (number of temperature detection elements), the number of temperature detection elements is 2 to 8.
11 pieces of m', preferably 1 piece of 3 to 6 pieces.

Temperature detection elements 14a configuring the average temperature detection means 14
The temperature sensing portion of L4d is located in the water near the surface of the water directly below the filler 8, where the sprayed water is falling, in order to detect changes in the cooling water temperature as quickly as possible.

The depth of the water should be as close to the water surface as possible without exposing the temperature sensitive part to the air, and should be within 30 mm below the water surface, preferably within bcrn.

Temperature detection element 14 a - 14 (l is attached to a float so that the temperature sensing part is always located at the same position below the water surface even when the water level of the cooling water pit 6 changes. Also, when the water level of the cooling water pit 6 changes, If not, the temperature detection cords 14a-14d are placed with the filling 8 so that the W=1HA section is located below the water surface.
It can also be attached to

The average temperature detection signal detected by the average temperature detection means 14 is input as a back signal to the temperature controller unit 11 and is compared with the temperature setting signal.

As the temperature controller unit 11, either an analog type or a digital type can be used.

Temperature adjustment=1 The @difference signal of the unit 11 is input to the rotation speed control unit 12, and the rotation speeds of the cooling/Q7 undrive motor 4 and the cooling fan 3 are automatically changed according to the deviation signal. As the rotation speed control unit 12, various types of rotation +1jlJ control devices can be used, such as commercial means such as an inverter, or mechanical means such as a stepless speed control unit.

Note that ]5 is an outlet temperature detection element provided in the cooling water outlet 1 BC2a, which is used to display the entire light of the outlet.

Since the present invention has the above-mentioned container configuration, the average temperature of the water in the cooling water pit 6 is detected by the half-average temperature detection means 14.
The detection signal is manually input to the temperature control unit 11 and compared with the temperature setting signal number, and the deviation signal is input to the temperature control unit 12. The +4sm motor 4 and the cooling fan 3 are changed in speed by the rotation speed '+jlJ i wholesale unit' 2 due to the deviation signal.In other words, when the detection signal is the setting signal, the rotation speed is changed to 'jnJ'. The number is increased, and conversely when it is small, it is decreased and automatically controlled so that the deviation signal becomes zero.As a result, the cooling fan 3
The air flow rate is increased or decreased, and the cooling water outlet temperature is the set temperature), that is, ′
#I will automatically apply 1[1j to the target temperature/falsity.

Note that the present invention is of course applicable not only to a cooling water system having one cooling water tower, but also to a cooling water system having a plurality of cooling water towers.

As described above, according to the present invention, the detection point is selected as the detection point immediately below the water surface of the cooling water pit, where cooling water temperature reduction can be detected earliest.
Since the average water droplet temperature is detected and the cooling water outlet temperature is automatically controlled, even in the case of a cooling water system where there are large fluctuations in return water temperature or timber frame, there is almost no time delay and water expansion can be achieved. It is possible to detect the change ``□'' during the number of rotations of the cooling fan ++ aia =) and smoothly without causing the pinching phenomenon, thereby achieving the effect of reliably automatically lowering the cooling water outlet temperature.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the system of the present invention, FIGS. 2 a and b are configuration explanatory diagrams showing rows of cooling towers applicable to the present invention, and FIG. 3 is another example. FIG. 1・・・・・・・・・Cold water tower, 2a・・・・・・・・・
Cooling water outlet piping, 2b...Cooling water return pipe, d13...Cooling fan, 4...
...Cooling fan, drive motor, 5...
・Uso' Reito 1j Louver for nitrogen intake, 6...
・・・Cooling water pit, 7・・・・・・December water test, 8
・・・・・・・・・Full IA product, 9・・・・・・・・・Engineer 1 Nominator, 10・・・・・・・・・Delivery pump, 1
1...Hyouno0 ii! i Nlj meter unit, 12......1 brittle failure control unit, 13......cooling water, 14a to i4d...
・・・・・・Temperature rte detection unit, 14t・・・・・・
...Temperature averaging processing unit, 14...
・Average+i! degree detection means. Representative Patent Attorney Hajime Ishito

Claims (1)

[Claims] In a cooling water system that has at least one cooling water tower and destroys the cooling water between the cooling water tower and the process, the average temperature of the water surface of the cooling water pit of the cooling tower is detected, and the average temperature is detected based on the average temperature detection signal. The rotation speed of the cooling fan of the cooling tower is automatically adjusted to increase or decrease the air volume to adjust the cooling water outlet temperature.
Cooling water outlet temperature control system in a cooling water tower with a wari cape.