JP2000234893A - Operation control method for ozone circulating cleaner of heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize reduction in overall size and economization of a facility by switching valves to form a circulation loop passing one of a plurality of juxtaposed heat exchangers and sucking ozone generated from a single ozone circulator into cleaning water in the circulation loop thereby cleaning a heat exchanger. SOLUTION: A heat exchanger comprising a plurality of juxtaposed heat exchangers A is provided with a single set of ozone circulator B. When some heat exchanger A is cleaned, a circulation pump 12 is operated while closing the shutoff valves 6, 7 associated with the water supply pipe 4 and the drainage pipe 5 of the heat exchangers A and opening a corresponding circulation valve 9. Consequently, water is circulated through a circulation loop 11 comprising the water supply pipe 4, the heat exchanger body 3, the drainage pipe 5 and an interconnecting pipe 8. Ozonized gas generated from an ozone generating source 14 is sucked through an ejector 13 into circulating water and mixed therewith to produce ozone dissolving water which is used for cleaning the heat exchangers A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method in an ozone circulation cleaning apparatus mainly applied to cleaning of a heat transfer surface of a heat exchange plate in a plate heat exchanger. The indirect heat exchange between the heat medium passing through the heat exchange unit and the water passing outside the heat exchange unit inside the heat exchanger body is performed through the heat transfer surface of the heat exchange unit. The present invention relates to an operation control method in an ozone circulation cleaning device for a heat exchanger.

[0002]

2. Description of the Related Art In a heat exchanger of this type, a heat exchanger which is indirectly heat-exchanged through a heat medium passing through a heat exchange portion charged into a heat exchanger body and a heat transfer surface of the heat exchange portion. Sewage, river water, seawater, or the like is often used as water passing through the inside of the main body. However, when sewage, river water, or seawater is used as internal passing water, microorganisms contained in the passing water adhere to the heat transfer surface of the heat exchange section over time and grow. Microbial fouling called slime is generated on the heat transfer surface, and the generation of the microbial fouling deteriorates the heat transfer performance and lowers the heat exchange efficiency.

In order to solve such a problem, the present applicant circulates water passing through the heat exchanger body, supplies ozonized gas to the circulation loop, and forcibly circulates ozone-dissolved water. In addition, an ozone circulating cleaning apparatus has been proposed which removes microbial stains attached to the heat transfer surface and suppresses attachment and growth of microorganisms to the heat transfer surface. The application of the ozone circulation cleaning device (hereinafter, referred to as a previously proposed device) already proposed by the present applicant to a plate heat exchanger will be described below with reference to FIGS. 4 and 5.

That is, the plate heat exchanger A is composed of an aggregate of a plurality of heat exchange plates 1. Each heat exchange plate 1 is connected to an inlet 2 A of a heat exchange unit 2 inserted in a heat exchanger body 3. The heat medium F is introduced into the heat exchanger body 3 and passed therethrough, and is led out from the outlet 2B.
The water W such as sewage, river water or seawater passes through the heat exchange plate 1.
And the heat medium F are indirectly exchanged heat via the heat transfer surfaces of the heat exchange plates 1.

The inlet 3A and the outlet 3 of the heat exchanger body 3
A water supply pipe 4 and a drainage pipe 5 are connected to B, respectively. Water supply cutoff valves 6 and 7 are interposed in the water supply pipe 4 and the drainage pipe 5, respectively. A position immediately downstream of the water shutoff valve 6 of the water supply pipe 4 and a position immediately upstream of the water shutoff valve 7 of the drainage pipe 5 are connected to each other through a communication pipe 8. A valve 9, a second circulating valve 10 composed of a check valve that allows the flow from the communication pipe 8 to the water supply pipe 4, and a circulating pump 12
The two water cutoff valves 6 and 7 are closed, and the first circulation valve 9 is opened to operate the circulation pump 12, so that the water supply pipe 4 and the heat exchanger A circulation loop 11 including the inside of the main body 3, the drain pipe 5 and the communication pipe 8 can be formed.

The communication pipe 8 on the suction side of the circulation pump 12 has an ozone supply pipe 15 and an ozone suction ejector 13.
An ozone generation source 14 is connected via the circulating loop 11. By operating the circulation pump 12 and the ozone generation source 14 in a state where the circulation loop 11 is formed, an ozonized gas is supplied into the circulation loop 11 to 11 is configured to forcibly circulate ozone-dissolved water.

[0007] An expansion tank 16, an air valve 28, and an ozone decomposer 17 filled with activated carbon are connected in series via a gas-liquid separator 27 at a position downstream of the first circulation valve 9 in the communication pipe 8 forming the circulation loop 11. A discharge pipe 18 is branched and connected to the expansion tank 16 to absorb an apparent increase in volume in the circulation loop 11 and to remove excess gas (mixed gas of waste ozone and oxygen) into the ozone decomposer 17. After being guided to the atmosphere. A water supply tank 21 is connected to the communication pipe 8 on the discharge side of the circulation pump 12 via a water supply pipe 22 provided with a check valve 24 and a water supply valve 23. Further, a drain pipe 26 is branched and connected to the communication pipe 8 via a drain valve 25.

In the ozone circulation cleaning apparatus for a plate heat exchanger having the above structure, as shown in FIG. 4, the water cutoff valves 6 and 7 are opened, the first circulation valve 9, the water supply valve 23 and the drain valve are opened. By passing water W such as sewage, river water, or seawater into the heat exchanger body 3 with the valve 25 closed, each of the heat exchange plates 1 charged in the heat exchanger body 3 and the passing water W is passed through. Are indirectly exchanged with the heat medium F passing through the heat exchange surfaces of the heat exchange plates 1.

If it is desired to perform the ozone circulation cleaning regularly or periodically in this state, as shown in FIG. 5, close the water cutoff valves 6 and 7 and open the first circulation valve 9. The circulation loop 11 is formed by the
Is opened, water is supplied from the water supply tank 21 to the circulation loop 11 to fill the circulation loop 11 with water, and then the circulation pump 1
2 and the operation of the ozone generation source 14 are started to forcibly circulate the ozone-dissolved water through the circulation loop 11 to remove microbial dirt called slime generated on the heat transfer surface of the heat exchange plates 1. Ozone circulation cleaning is performed to suppress the attachment and growth of microorganisms to the heat transfer surface.

After the ozone circulation cleaning as described above, the operation of the circulation pump 12 is stopped, the water supply valve 23 is closed, and the drain valve 25 is opened, so that the cleaning of the circulation loop 11 is completed. 5 is discharged to the drain pipe 26, and then the first circulation valve 9, the water supply valve 23 and the drain valve 25 are closed, and the water cutoff valves 6 and 7 are opened, so that the state shown in FIG. That is, the passing water W inside the heat exchanger main body 3 and the heat medium F passing through the heat exchange plates 1 charged in the heat exchanger main body 3 are passed through the heat transfer surfaces of the heat exchange plates 1. To return to the state of indirect heat exchange.

[0011]

According to the proposed apparatus having the above-described structure, the cleaning is performed in a manner different from the disassembly cleaning, the stationary cleaning using a chemical called CIP or the stationary cleaning using warm water. , Ozone cleaning treatment that can remove microbial dirt on the heat transfer surface of the heat exchange section and suppress the adhesion and growth of microorganisms on the heat transfer surface that causes the dirt is labor-saving and labor-saving. On the other hand, the proposed device has the advantage that it can be efficiently executed, but the proposed device has one heat exchanger or one heat exchanger unit (which is composed of a plurality of heat exchangers and piping connecting them, These heat exchangers are always operated at the same time, and are not independent units.) Each of these units is equipped with one set of ozone circulating device. Or multiple In constructing a system for cleaning the heat exchanger units of the system, a set number of ozone circulators corresponding to the number of heat exchangers to be cleaned or the number of heat exchanger units are required, and the pipes, etc., were very large in size. In addition to complicated equipment, there remains a problem that the equipment cost is inevitably enormous.

The present invention has been made in view of the above circumstances, and a plurality of heat exchangers can be washed with a single set of ozone circulating devices, thereby reducing the size and cost of the entire equipment. Ozone circulation cleaning of heat exchangers that can efficiently and rationally perform cleaning of multiple heat exchangers without causing troubles such as simultaneous transfer to cleaning operation and time loss. It is an object of the present invention to provide an operation control method in a device.

[0013]

In order to achieve the above-mentioned object, an operation control method for an ozone circulation cleaning apparatus for a heat exchanger according to the present invention is directed to a method for controlling heat passing through a heat exchange section charged into a heat exchanger body. Heat exchange between the medium and water supplied and discharged inside the heat exchanger body through the outside of the heat exchange section through a water supply pipe and a drain pipe connected to an inlet and an outlet of the heat exchanger body, respectively. A plurality of heat exchangers configured to allow indirect heat exchange via the heat transfer surface of the section, and a plurality of heat exchangers each having a water cutoff valve interposed in the water supply pipe and the drain pipe. A communication pipe that connects the downstream side of the water supply cutoff valve of the water supply pipe and the upstream side of the water supply cutoff valve of the discharge pipe to each other through a circulation valve, a circulation pump provided in the communication pipe, and an ozone generation source. Having both water shutoff valves in each of the heat exchangers closed. And, by operating the circulation pump by opening the circulation valve, water supply pipe, the heat exchanger body,
A single loop configured to form a circulation loop including a drain pipe and a communication pipe, and configured to forcibly circulate ozone-dissolved water in the circulation loop by supplying ozone generated by the ozone generation source to the circulation loop. An operation control method for an ozone circulation cleaning device of a heat exchanger including a set of ozone circulation devices, wherein priorities are set in advance for the plurality of heat exchangers, When a cleaning signal using the fully-closed signal of the shut-off valve is transmitted from the central control unit, it is determined whether or not the cleaning operation is being performed in order from the heat exchanger having the highest priority, and any one of the heat exchangers is determined. When it is determined that the exchanger is in the cleaning operation, it is determined that all the plurality of heat exchangers are not performing the cleaning operation while restricting the cleaning operation of the remaining heat exchangers until the cleaning is completed. Case and wash When the cleaning operation of the operating heat exchanger is completed, the cleaning operation is started from the heat exchanger having the higher priority, and the cleaning signal is transmitted to the central control unit to prohibit the heat exchange operation of the heat exchanger. It is characterized by performing operation control as follows.

According to the present invention, even when a plurality of cleaning signals using the fully closed signals of the two water cutoff valves in the plurality of heat exchangers are transmitted from the central control unit, the plurality of heat exchangers are transmitted to the plurality of heat exchangers. It is possible to restrict the start of the ozone circulation cleaning operation at the same time and to shift to the cleaning operation in order from the heat exchanger having the highest priority, and when a cleaning signal is transmitted, any one of the heat exchangers is transmitted. When the heat exchanger is in the cleaning operation, it is possible to restrict the transition of another heat exchanger to the cleaning operation until the cleaning of the heat exchanger is completed. Further, when one heat exchanger is in the cleaning operation, the cleaning signal is transmitted to the central control unit, and the heat exchange operation of the heat exchanger can be prohibited. By performing such operation control, a plurality of heat exchangers can be used while reducing the size and cost of the entire facility, such as performing ozone circulation cleaning for a plurality of heat exchangers using a single set of ozone circulation devices. A plurality of heat exchangers can be sequentially and automatically cleaned efficiently under a set priority without causing trouble such as shifting to a cleaning operation at the same time or causing a time loss.

In particular, in the operation control method as described above, before starting the cleaning operation of each heat exchanger, it is checked whether a predetermined time has elapsed since the previous cleaning, and if the predetermined time has not elapsed, the cleaning operation is started. Is provided, it is possible to eliminate waste that is washed at an unnecessarily high frequency, and it is possible to further increase the efficiency of ozone circulation washing for a plurality of heat exchangers.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an ozone circulation cleaning apparatus for a plate heat exchanger applied to the practice of the method of the present invention. In the figure, A-1, A-2, A-3 ~
A to N are a plurality of heat exchangers (a plurality of heat exchangers or a plurality of heat exchanger units) installed in parallel, and the plurality of heat exchangers A-1, A-2, A-3,. Since the configuration of A-N is the same as that of the heat exchanger A in the proposed device shown in FIGS. 4 and 5 as shown in FIG. 2, the same or corresponding parts are denoted by the same reference numerals and detailed description thereof will be given. Is omitted.

In FIG. 1, B is a single set of ozone circulating apparatus. As shown in FIG. 2, this ozone circulating apparatus B has a single communication pipe 8, a circulation pump 12, an ozone supply pipe 15, and an ozone supply pipe 15. Ejector 13 for inhalation and ozone source 14
A plurality of first circulation valves 9 and second circulation valves 10 comprising check valves, the number of which is equal to the number of the heat exchangers 3; 5
And the downstream sides of the plurality of second circulation valves 10 are connected to the water supply pipe 4 via branch pipes 31, respectively, and the heat exchangers A (A-1, A-2, A-3 to AN) are provided. ), The circulating pump 12 is operated in a state in which the two water shutoff valves 6 and 7 are closed and the corresponding first circulating valve 9 is opened, so that the branch pipe 31, the water supply pipe 4, and the heat exchanger body 3, a drainage pipe 5, a branch pipe 30, and a communication pipe 8, a circulation loop 11 can be formed, and the ozone generation source 14 is operated in the state of the formation of the circulation loop 11 so that ozone is introduced into the circulation loop 11. The ozone-dissolved water is forcibly circulated through the circulation loop 11 by supplying a chemical gas.

The ozone circulating apparatus B has, in addition to the above-described configuration, a plurality of first pipes formed by a communication pipe 8 forming the circulating loop 11.
A discharge pipe 18 in which an expansion tank 16, an air valve 28, and an ozone decomposer 17 filled with activated carbon are interposed in series via a common gas-liquid separator 27 at a position downstream of the circulation valve 9 is branched and connected.
A water supply tank 21 is connected to the communication pipe 8 on the discharge side of the circulation pump 12 via a water supply pipe 22 provided with a check valve 24 and a water supply valve 23. A drain pipe 26 is branched and connected via a drain valve 25.

In FIG. 1, C is a central control panel, D is
Is a controller for controlling the cleaning operation, and centralizes a cleaning signal using the fully closed signal of the water cutoff valves 6 and 7 in each of the heat exchangers A-1, A-2 and A-3 to AN. By transmitting from the control panel C to the controller D, one of the first circulation valves 9 in the ozone circulation device B is opened to form the circulation loop 11 and the circulation loop 11
A predetermined cleaning operation is performed by forcibly circulating ozone-dissolved water.

The controller D is composed of a computer. The controller D is set in advance so that the priorities for the plurality of heat exchangers A are A-1, A-2, A-3, and AN. Memory for each heat exchanger A-
1, A-2, A-3 to AN, a timer means for measuring the elapsed time from the last cleaning operation (start or end), the measured elapsed time t1 and the predetermined time t0
By comparing {generally set to one day (24 hours)}, only when t1 ≧ t0, a time lapse checking means allowing the start of the cleaning operation and a signal during cleaning are transmitted to the central control panel C. And the like. Further, when the central control panel C receives the signal during cleaning, the water shutoff valves 6 and 7 in the heat exchanger A to be cleaned are kept in the fully closed state, and the heat exchange operation of the heat exchanger A is prohibited. An interlock is provided.

Next, the cleaning operation in the ozone circulation cleaning apparatus for the plate heat exchanger configured as described above will be described with reference to the flowchart of FIG.

First, a plurality of heat exchangers A-1, A-2, A-3 to AN are sent from the central control panel C to the controller D.
A cleaning signal using the fully closed signal of each of the water cutoff valves 6 and 7 is transmitted. The controller D having received the cleaning signal determines which of the plurality of heat exchangers A the cleaning signal is based on in the priority order (A-1 → A-).
2 → A−3 → AN). Subsequently, it is determined whether or not the water cutoff valves 6 and 7 in the determined heat exchanger A to be cleaned are maintained in the fully closed state by timer counting for a predetermined time. It is determined whether or not A is performing a cleaning operation.

In this determination, when it is determined that any one of the cleaning operations is being performed, the cleaning operation for the other heat exchanger A is regulated until the cleaning is completed.
If it is determined that all of the plurality of heat exchangers A are not in the cleaning operation and if the cleaning operation of the heat exchanger A during the cleaning operation is completed, the time from the previous cleaning operation in the heat exchanger A to be cleaned is Whether or not the predetermined time t0 has elapsed is confirmed by comparison with the elapsed time t1 measured by a timer. This confirmation is for preventing the washing from being performed at an unnecessarily high frequency.
Only when it is 0, it is determined whether or not the central control panel C is in an operation standby mode in which the closing operation of the water cutoff valves 6 and 7 in the heat exchanger A to be cleaned is maintained. If not, switch to the operation standby mode.

Thereafter, the first circulation valve 9 corresponding to the heat exchanger A to be cleaned in the ozone circulation device B is opened, and the circulation pump 12 is operated, so that the branch pipe 31,
Water supply pipe 4, inside heat exchanger body 3, drain pipe 5, branch pipe 3
Ozone gas is supplied into the circulation loop 11 by operating the ozone generation source 14 in a state where the circulation loop 11 is formed, and the ozone generation source 14 is operated in the state where the circulation loop 11 is formed. Water is forcibly circulated to start the ozone circulation cleaning for the heat exchanger A to be cleaned, and a signal during cleaning is transmitted to the central control panel C. While receiving the in-wash signal, the water shutoff valves 6 and 7 in the heat exchanger A to be washed are kept in the fully closed state from the central control panel C to the controller D, and the heat exchanger A An interlock signal for inhibiting the heat exchange operation will be transmitted.

With the above operation control operation, the ozone circulating cleaning for a plurality of heat exchangers A is performed by using a single set of ozone circulating devices B, thereby reducing the size and cost of the entire equipment, and reducing the cost. Even if a plurality of cleaning signals are transmitted from the control panel C to the controller D at the same time, if a plurality of heat exchangers A shift to the cleaning operation at the same time, or if any one of the heat exchangers A is performing the cleaning operation, There is no occurrence of operation troubles such as the transfer of the other heat exchanger A to the cleaning operation. In addition, when all of the plurality of heat exchangers A are not in the cleaning operation, the operation can be sequentially shifted to the cleaning operation based on the set priority, and no time loss occurs and the plurality of heat exchangers A can be operated. A can be washed automatically and efficiently.

[0026]

As described above, according to the present invention,
In the configuration of the ozone circulation cleaning system for a plurality of heat exchangers or a plurality of heat exchanger units, only a single set of ozone circulation devices needs to be used, and the overall equipment can be reduced in size and economical. Nevertheless, the operation of multiple heat exchangers is automatically performed in accordance with the set priority without causing any operation troubles such as simultaneous operation of multiple heat exchangers for cleaning operation and time loss. This has the effect of enabling efficient and efficient cleaning.

In particular, by providing a step of checking whether or not a predetermined time has elapsed since the last cleaning before starting the cleaning operation of each heat exchanger and regulating the start of the cleaning operation if the predetermined time has not elapsed, Unnecessarily high frequency of waste can be eliminated, and the efficiency of ozone circulation cleaning for a plurality of heat exchangers can be further increased.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ozone circulation cleaning apparatus for a plate heat exchanger applied to the practice of the method of the present invention.

FIG. 2 is an enlarged configuration diagram of a main part in the ozone circulation cleaning device.

FIG. 3 is a flowchart illustrating a cleaning operation by the ozone circulation cleaning device.

FIG. 4 is an overall configuration diagram showing a heat exchange operation state in the ozone circulation cleaning device of the plate heat exchanger already proposed by the present applicant.

FIG. 5 is an overall configuration diagram showing an ozone circulation cleaning operation in the ozone circulation cleaning device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchange plate (heat exchange part) 3 Heat exchanger main body 4 Water supply pipe 5 Drain pipe 6,7 Water cutoff valve 8 Communication pipe 9,10 Circulation valve 11 Circulation loop 12 Circulation pump 14 Ozone generation source A (A-1) , A-2, A-3 to AN) Heat exchanger B Ozone circulation device C Central control panel D Controller for cleaning operation control W Water F Heat medium

Claims (2)

[Claims] 1. A heat medium passing through a heat exchange part charged in a heat exchanger body and a water supply pipe and a drain pipe connected to an inlet and an outlet of the heat exchanger body, respectively, inside the heat exchanger body. It is configured to indirectly exchange heat with water supplied and discharged so as to pass through the outside of the heat exchange unit through a heat transfer surface of the heat exchange unit, and that water flows through the water supply pipe and the drain pipe, respectively. A plurality of heat exchangers provided with a shutoff valve, and a downstream side of a water supply shutoff valve of a water supply pipe and an upstream side of a waterflow cutoff valve of a discharge pipe of each of the plurality of heat exchangers are mutually connected via a circulation valve. It has a communication pipe for communication and connection, a circulation pump and an ozone generation source interposed in the communication pipe, closes both water cutoff valves in each of the heat exchangers, and opens the circulation valve. By operating the circulation pump, the water supply pipe, the inside of the heat exchanger body, the drain pipe and the communication pipe A single set of ozone circulating devices that can form a circulation loop that is configured to forcibly circulate ozone-dissolved water through the circulation loop by supplying ozone generated by the ozone generation source to the circulation loop. An operation control method in an ozone circulation cleaning apparatus for a heat exchanger, wherein priorities are set in advance for the plurality of heat exchangers, and a fully closed signal of both water shutoff valves in each heat exchanger is provided. When the cleaning signal using the is transmitted from the central control unit, it is determined whether or not the cleaning operation is being performed in order from the heat exchanger having the highest priority, and any one of the heat exchangers is performing the cleaning operation. When it is determined that the cleaning operation of the remaining heat exchangers is restricted until the cleaning thereof is completed, while it is determined that all of the plurality of heat exchangers are not performing the cleaning operation and during the cleaning operation, Heat exchanger If Kiyoshi operation is completed with starting the cleaning operation from an early heat exchanger of the priority,
An operation control method for an ozone circulation cleaning apparatus for a heat exchanger, comprising: transmitting a cleaning signal to a central control unit to perform operation control to prohibit a heat exchange operation of the heat exchanger. 2. Before starting the cleaning operation of each heat exchanger, it is confirmed whether or not a predetermined time has elapsed since the last cleaning, and if not, the start of the cleaning operation is regulated. The operation control method for an ozone circulation cleaning apparatus for a heat exchanger according to claim 1.