JPH0753736Y2 - Temperature controller for paint distribution system - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a paint flow system in which paint is circulated between a preparation tank and each coating machine, in order to adjust the temperature of the paint flowing in the system to adjust its viscosity. The present invention relates to a control device, and more particularly, to an improvement in a pipe configuration for supplying hot water and cold water to a heat exchanger used for the temperature control.

INDUSTRIAL APPLICABILITY The present invention is particularly useful for a tunnel-type painting booth, for example, a painting booth of an automobile factory equipped with a paint circulation system that supplies the painting tank from a preparation tank to each predetermined painting place in the booth and then collects the paint again to the preparation tank. Is.

(Prior Art) Conventionally, in a paint circulation system such as an automobile paint booth, in order to maintain a stable paint discharge amount from a paint machine and ensure good paint quality, it is always necessary to appropriately adjust the viscosity of the paint. An apparatus for controlling the temperature of the paint flowing through the circulation system to a desired value by heating or cooling is incorporated.

Such temperature control is generally achieved by incorporating a heat exchanger into the paint circulation pipe that communicates with the coating machine in the coating booth, so that hot water (e.g., 25-40 ° C water) and cold water (e.g.
The temperature is controlled by heat exchange by supplying water (° C. water) to the heat exchanger.

FIG. 3 shows a characteristic example of the temperature control device. This apparatus comprises a single heat exchanger 2, a cold water tank 14 and a hot water tank, in which a plurality of or n (= integer integers of 2 or more) paint tubes 1 ... In communication with a coating machine (not shown) are incorporated. The cold water tank 14 and the hot water tank 15 are respectively connected to the heat exchanger 2 by the cold water supply pipe 5 and the hot water supply pipe 6 in which the switching valve 9 is interposed, respectively, and as the return path, the switching valve is provided. The cold water tank 14 and the hot water tank 15 are respectively connected to the heat exchanger 2 by a cold water recovery pipe 7 and a hot water recovery pipe 8 in which 9 are respectively interposed. The cold water and hot water supply pipes 5 and 6 have pumps 18 and 19 interposed therebetween and return pipes 21 and 22 with a throttle valve 20 interposed therebetween. Further, the supply pipes 5 and 6 and the recovery pipes 7 and 8 merge near the heat exchanger 2, and in fact, the confluence pipes 16 and 17 merge into the heat exchanger 2.
And combined with each.

Thus, in controlling the paint temperature in the above conventional apparatus, when the paint temperature is lowered, cold water is supplied from the tank 14 to the heat exchanger 2 through the pipe 5 by the operation of the pump 18, and then the heat is exchanged. When water is collected again in the tank 14 through the pipe 7 and when the temperature of the paint is increased, hot water is supplied from the tank 15 to the heat exchanger 2 through the pipe 6 by operating the pump 19.
After that, the heat-exchanged water is recovered again in the tank 15 via the pipe 8, and the amounts of cold water and hot water to be supplied are adjusted by adjusting the degree of opening of the switching valve 9.

Further, when the water flowing through the heat exchanger 2 is changed from cold water to hot water or from hot water to cold water, the opening / closing operation of the switching valve 9 ... Switching valve 9 on the water recovery side is slightly delayed after opening / closing of switching valve 9 on the water side
Was opening and closing.

In the supply of hot and cold water, generally, the supply amount of cold water or hot water is relatively high for a while after the start of the control, that is, while the actual temperature of the paint is largely deviated from the target temperature. We have adopted a procedure in which a large amount of water is set, then the amount of supplied water is gradually reduced as the temperature shift becomes smaller, and finally the supply of water is stopped.

(Problems to be solved by the invention) However, since the above-mentioned conventional device has a piping configuration for directly supplying hot and cold water from the tank to the heat exchanger 2, the actual paint temperature and the target same temperature are When the deviation is large (that is, for a while after the start of control), it does not matter so much, but at the stage where the deviation of the temperature is small and the supply amount of cold water or hot water is small (that is, during the coating of the product). Causes a considerable difference in the degree and speed of heat exchange between the paint pipes that come in faster contact with the hot and cold water supplied in the heat exchanger and the paint pipes that come in relatively slow contact, resulting in control. In some cases, there was a variation in the paint temperature of each subsequent tube that would cause a problem in the actual painting process.

Further, if the switching valve 9 is opened / closed incorrectly and the operation time difference between the water supply side valve 9 and the water recovery side valve 9 is improper, the cold water directly flows into the hot water flow system or the hot water directly flows into the cold water. There was also a problem that it would flow into the distribution system and cause the temperature change of hot and cold water. The change in temperature of hot and cold water is a problem that leads to instability in control of the paint temperature, and sometimes adversely affects the coating quality.

The present invention has been made in consideration of the above circumstances, and its purpose is not only in the stage where the difference between the actual paint temperature and the target paint temperature is large, but also in the stage where the difference is small. However, the temperature of the paint can be controlled with high accuracy so that the paint temperature after control is uniform for all paint pipes, and very high control stability can be obtained, and direct mixing of hot water and cold water can be avoided. A technical object of the present invention is to provide a temperature control device for a paint flow system, which makes it possible to keep the amount of water supplied to a heat exchanger constant regardless of the difference between the actual temperature and the target temperature. Especially.

(Means for Solving the Problem) The present invention forms a water circulation path having a temperature intermediate between cold water and hot water between a heat exchanger and circulates the intermediate temperature water and replenishes the cold water and the hot water. It is designed to always supply a certain amount of water or more to the heat exchanger.

That is, the present invention is a device for controlling the temperature of each paint by circulating hot and cold water in a single heat exchanger incorporating a plurality of paint pipes, in which a pump is installed between the heat exchanger and the intermediate water tank. The present invention relates to a temperature control device for a paint distribution system, which is provided with a pipe through which water circulates during operation, and in which hot water and cold water supply pipes and hot water and cold water recovery pipes are connected to the circulation pipe or an intermediate water tank. .

The present invention allows water of low temperature or elevated temperature to flow to a heat exchanger incorporating paint tubes, and particularly effectively to a single heat exchanger incorporating multiple paint tubes. ,
It can be applied to a device that controls the temperature of each paint.
The heat exchanger preferably incorporates a plurality of paint pipes for each paint color, such as a conventional double pipe structure type heat exchanger.

The control device of the present invention comprises a circulation pipe for circulating water having an intermediate temperature between cold water and hot water between the heat exchanger and the intermediate water tank. A general piping configuration for water circulation, which incorporates valves, etc., is sufficient.

Further, the intermediate water tank may be a tank capable of storing the above intermediate temperature water, and the special configuration and elements are
It may be provided, but is not particularly required.

However, the capacity of the pump in the circulation pipe should be set beyond the minimum required capacity to supply a large flow rate of water to the heat exchanger so as to keep the paint temperature constant for each paint pipe. It is preferable that the total volume of the inside of the pipe and the intermediate water tank should be set to a volume corresponding to the flow rate of the circulating water determined by the pump capacity.

The cold water supply pipe and the cold water supply pipe are led from a cold water source, for example, a cold water tank via a switching valve or a pump, and are connected to the circulation pipe or the intermediate water tank. Similarly, the hot water supply pipe and the recovery pipe are led from a hot water source, for example, a hot water tank via a switching valve, a pump, etc., and are connected to the circulation pipe or the intermediate water tank.

Next, a method of operating the device of the present invention will be described. As one of the methods, at the beginning when there is a large difference between the actual paint temperature in the paint pipe and the target temperature, a relatively large amount of cold water or hot water is supplied to the intermediate water tank or circulation pipe from those supply pipes. While supplying water to the heat exchanger, the water is circulated between the intermediate water tank and the heat exchanger by the operation of the pump, and water close to the temperature of the cold water or the hot water is supplied to the heat exchanger, after which the temperature difference gradually decreases. In accordance with the above, the amount of cold or hot water to be supplied will be reduced, and when there is no temperature difference, almost all of the water in the intermediate water tank will be supplied to the heat exchanger, and cold or hot water will be supplied. There is a procedure to keep the amount to a small amount as needed.

Also, as another method, during the first time when the actual paint temperature and the target temperature are largely different, the water in the intermediate water tank is not circulated, but only cold water or hot water is sent to the circulation pipe and supplied to the heat exchanger. Then, at the stage where the temperature difference becomes smaller, the circulation of water in the intermediate water tank is started instead of cold water or warm water, the circulating water amount is gradually increased, and at the end, There is a procedure in which all the water in the intermediate water tank is supplied to the heat exchanger, and the amount of cold or hot water supplied is kept to a minimum.

(Operation) In the present invention, since one circulation pipe is formed between the intermediate water tank and the heat exchanger, by circulating water in the pipe, especially in the tank by operating the pump, It is possible to supply water to the heat exchanger, that is to say at least a flow rate of water such that there is no variation in paint temperature for each paint pipe. Since the flow rate of the circulating water does not have to be changed in relation to the magnitude of the deviation between the actual paint temperature and the target temperature, the steady water amount can always be maintained stable. Therefore, the paint temperature in the paint tube can be controlled uniformly for all tubes.

Also, when changing the supply water to the heat exchanger between cold water and hot water, or between the water from the intermediate water tank, even if the operation of changing the supply water is mistaken, the temperature between the cold water and the hot water The above-mentioned water mainly flows into the intermediate water tank and partly into the recovery channel of the hot / cold water, and the cold water and the hot water themselves do not directly flow into these recovery channels. Therefore, even if an erroneous operation is performed, the heat energy loss becomes smaller.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 As shown in FIG. 1, the apparatus of this embodiment has a double-tube heat exchanger 2 incorporating n (= integer of 2 or more) paint pipes 1 ... Connected to a coating machine. And the heat exchanger 2,
An intermediate water tank 3 containing water having an intermediate temperature between cold water and warm water (for example, water at room temperature) is originally connected to a pump 10 to form one circulation pipe 4. The water in the water tank 3 circulates in the pipe 4 as shown by the arrow a and is supplied to the heat exchanger 2.

Then, a cold water supply pipe 5 from a cold water tank (not shown)
And a hot water supply pipe 6 from a hot water tank (not shown) to the circulation pipe 4 slightly upstream of the water inlet of the heat exchanger 2,
A cold water recovery pipe 7 returning to the cold water tank and a hot water recovery pipe 8 returning to the hot water tank are connected to a circulation pipe 4 slightly downstream of the water outlet of the heat exchanger 2.

The circulation pipe 4, both cold water and hot water supply pipes 5 and 6, and both cold water and hot water recovery pipes 7 and 8 are provided with switching valves 9 at appropriate positions. In the figure,
Reference numeral 11 indicates a water discharge pipe in the intermediate tank.

In order to control the paint temperature, the circulating water from the intermediate water tank 3 is supplied to the heat exchanger 2 by switching the valves 9 based on an automatic control device (not shown), or the circulating water and the supply pipe 5 are supplied. , 6 is mixed with cold water or hot water at an appropriate ratio in the confluence section 23, and the mixed water is supplied to the heat exchanger 2, or
Alternatively, by supplying cold or hot water directly from the pipes 5, 6 to the heat exchanger 2, more specifically, for example by supplying water to the heat exchanger 2 according to the two procedures described above. , The paint in the paint pipe 1 ... Is adjusted to a desired temperature.

In this embodiment, regardless of whether the difference between the actual paint temperature and the target temperature is large or small, it is possible to always supply a certain amount of water or more to the heat exchanger 2 from the intermediate water tank or the like, and The paint temperature could be adjusted uniformly for all paint tubes 1 ...

In particular, in the apparatus of this embodiment, hot and cold water is sent from the supply pipes 5 and 6 to the heat exchanger 2 without passing through the tank 3, so that the cold water and the hot water are supplied to the heat exchanger 2 while maintaining almost that temperature. And has the advantage that the paint temperature can be adjusted quickly.

Further, even if an error occurs in the time difference operation between the water supply side and the water recovery side, the cold water (hot water) supplied to the heat exchanger 2
Does not flow into the collection pipe for hot water (cold water) as it is, but is collected in the intermediate water tank 3 and in the form of being mixed with the water in the pipe 4, mixing the hot water into the cold water source and the cold water into the hot water source. No contamination occurred.

Embodiment 2 As shown in FIG. 2, the temperature control apparatus of this embodiment has a heat exchanger 2 and an intermediate water tank 3 each having the same construction as that of Embodiment 1, incorporating n paint pipes 1 ... The circulation pipe 4 and the pump 10 are provided, and water is circulated between the heat exchanger 2 and the tank 3 by the pump operation as shown by an arrow a.

In this embodiment, a cold water supply pipe 5 connected to a cold water source (not shown) and a hot water supply pipe 6 connected to a hot water source (not shown) are brought into confluence via a switching valve 9, respectively, and the confluent pipe is joined.
12 is connected to the intermediate water tank 3, and another merging pipe 13 branched from the circulation pipe 4 is branched into a cold water recovery pipe 7 and a hot water recovery pipe 8 and the switching valves 9 are respectively connected to the cold water source and the hot water source. It is arranged through.

Each switching valve 9 and pump 10 are connected to an automatic control device (not shown), and operate according to a control program relating to the temperature and flow rate of water. Also,
Such a control device is provided with a detection unit (not shown, which is known) for measuring temperature and flow rate,
Provide control data to the program.

The temperature control of the paint in this apparatus is basically performed in the same manner as in Example 1, except that the hot and cold water supply pipe 5,
Since 6 is connected to the intermediate water tank 3, the original water in the tank 3 or the mixed water of this and cold water or hot water is supplied to the heat exchanger 2 by the procedure according to the case of the first embodiment. Will be performed.

In the apparatus of this embodiment, the paint temperature is always made uniform for all the paint pipes 1 ... Even when the deviation between the actual paint temperature and the target temperature is large or small. Could be adjusted.

In particular, in the apparatus of this embodiment, the water in the tank 3 and the mixed water of cold water or hot water are sent to the heat exchanger 2, so that the temperature of the circulating water in the heat exchanger 2 does not change rapidly. ,
It has the advantage that the stability of temperature control is particularly good.

Further, also in this device, as in the case of Example 1, when the wrong time difference operation occurred, the mixing of the hot water into the cold water source and the mixing of the cold water into the hot water source did not occur.

(Effect of the Invention) As described above, the temperature control device for the paint flow system according to the present invention forms the circulation water passage between the intermediate water tank and the heat exchanger to circulate the intermediate temperature water in the tank. By supplying cold water or hot water, it is possible to always supply a certain amount or more of water to the heat exchanger, so of course there is a large difference between the actual paint temperature and the target paint temperature. Even when the deviation is small, it is possible to perform highly accurate temperature control so that the paint temperature after passing through the heat exchanger will be uniform for all paint pipes, and it has excellent control stability. Is obtained.

In addition, the device according to the present invention, when changing the supply water to the heat exchanger between cold water and hot water, or between these and the water from the intermediate water tank, even if the changing operation is mistaken, Since it does not directly mix with hot water, it is also advantageous in terms of heat utilization.

[Brief description of drawings]

FIG. 1 is a piping configuration diagram showing a temperature control device of a first embodiment of the present invention, FIG. 2 is a piping configuration diagram showing a temperature control device of a second embodiment of the present invention, and FIG. 3 is a conventional paint distribution system. It is a piping lineblock diagram showing a temperature control device. In the figure, 1 ... Paint pipe 2 ... Heat exchanger 3 ... Intermediate water tank 4 ... Circulation pipe 5 ... Cold water supply pipe 6 ... Hot water supply pipe 7 ... Cold water recovery pipe 8 ... Hot water recovery pipe 9 ...... Switching valve 10 ...... Pump a ...... Water flow direction in circulation piping

Claims (1)

[Scope of utility model registration request] 1. A device for controlling the temperature of each paint by circulating hot and cold water through one heat exchanger incorporating a plurality of paint pipes, by operating a pump between the heat exchanger and the intermediate water tank. A temperature control device for a paint distribution system, comprising: a pipe through which water circulates; and a hot water and cold water supply pipe and a hot water and cold water recovery pipe connected to the circulation pipe or an intermediate water tank.