Heat exchanger for wasted heat with its cleaning apparatus

A waste heat recovery system includes: a tank; heat exchange pipes connected with one another in the form of a ‘S’ shape in multiple steps inside the tank and having city water flow pipes bound up into a bundle; circulation leading plates mounted between the heat exchange pipes for inducing a flow of waste water; movable nozzles mounted on the circulation leading plates and connected with a high pressure water pipe for spraying high pressure water onto the surface of the heat exchange pipe or having a brush for cleaning the surface of the heat exchange pipe; a nozzle driving part for driving the movable nozzle by means of a driving motor; and waste water inlet and outlet for flowing hot waste water from the upper portion to the lower portion of the tank and city water inlet and outlet for flowing city water from the lower portion to the upper portion of the tank.

TECHNICAL FIELD

The present invention relates to a waste heat recovery system with a cleaning apparatus for recovering heat of water wasted from a public bath, a factory or a swimming pool, and more particularly, to a waste heat recovery system with a cleaning apparatus, which can allow an effective recovery of waste heat and an easy cleaning of the waste heat recovery system, thereby increasing heat exchange efficiency and providing an easy maintenance.

BACKGROUND ART

In general, a waste heat recovery system for reusing heat of water wasted from a place where a great deal of hot water is used, such as a public bath, a swimming pool, a fish-farm, or other place, heats cold water inside a heat exchange pipe in such a manner that the heat exchange pipe for carrying cold water is installed inside a water tank and waste water of high temperature discharged from the public bath is induced into the water tank so as to transfer heat between the heat exchange pipe and the waste water. However, in the conventional waste heat recovery system, the waste water is strained through a filter before being induced into the water tank to prevent stopping of the water tank or a flow channel due to foreign matters because foreign matters or wastes contained in the waste water are induced into the water tank. However, the conventional waste heat recovery system has a problem in that it is difficult to transfer heat smoothly as the foreign matters are stained on the external surface of the heat exchange pipe or sludge is formed on the external surface of the heat exchange pipe in spite of installation of the filtering device while the waste heat recovery system is used for a long time. Therefore, the water tank has a cover or a hole for cleaning, and so, a user can remove the foreign matters using a brush. However, it is difficult to clean a conduit and the heat exchange pipe since the conduit and the heat exchange pipe are in a spiral form or have a complicated shape to increase the surface area for heat transfer.

DISCLOSURE OF INVENTION

Accordingly, it is an object of the present invention to provide a waste heat recovery system with a cleaning apparatus, which can easily clean a heat exchange pipe and provide a convenient maintenance. Another object of the present invention is to provide a waste heat recovery system with a cleaning apparatus, which can increase a heat recovery efficiency of waste heat.

To achieve the above objects, the present invention provides a waste heat recovery system with a cleaning apparatus including: a tank; a number of heat exchange pipes connected with one another in the form of a ‘S’ shape in multiple steps inside the tank and having a number of city water flow pipes bound up into a bundle; circulation leading plates mounted between the heat exchange pipes for inducing a flow of waste water; movable nozzles mounted on the circulation leading plates respectively, the movable nozzle being connected with a high pressure water pipe for spraying high pressure water onto the surface of the heat exchange pipe or having a brush for cleaning the surface of the heat exchange pipe; a nozzle driving part for driving the movable nozzle by means of a driving motor; and waste water inlet and outlet for flowing hot waste water from the upper portion to the lower portion of the tank and city water inlet and outlet for flowing city water from the lower portion to the upper portion of the tank.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings.

As shown inFIGS. 1 and 2, a waste heat recovery system includes: a tank100; a number of heat exchange pipes500connected with one another in the form of a ‘S’ shape in multiple steps inside the tank100and having a number of city water flow pipes bound up into a bundle; circulation leading plates200mounted between the heat exchange pipes500to form waste water paths; a movable nozzle part mounted on the outer surface of the circulation leading plate200and connected with a high pressure water induction pipe300; a nozzle driving part mounted inside the circulation leading plate for driving the movable nozzle part along a guide rail230formed on the circulation leading plate200; a driving part mounted on the outer surface of an assembly plate170of the tank100for driving the nozzle driving part; and a position sensing part connected to the driving part for controlling the rotational direction of a driving motor using a position sensor for sensing position of the movable nozzle part.

The driving part includes a driving pulley450mounted on a shaft of a driving motor400, a number of slave pulleys460for transferring driving power of the driving motor400, and a belt470for connecting the driving pulley and the slave pulley. The slave pulleys have the same number as the nozzle driving parts mounted on the circulation leading plates200, so that driving power of the driving motor can be transferred to the entire nozzle driving parts of the circulation leading plates200.

As shown inFIG. 2, a number of the circulation leading plates200are welded inside the assembly plate at regular intervals, and rectangular channels310are mounted at right and left sides of the outer surface of the assembly plate and connected with the high pressure water induction pipe300. The assembly plate170is screwed to a tank flange180formed at a side of the tank100and assembled with the tank100. An electronic valve340is mounted on the high pressure water induction pipe300for controlling induction of high pressure water.

The tank100includes a number of tank inspection holes130formed in a side portion thereof, a city water inlet140and a waste water outlet120formed in the lower portion of the side thereof, and a city water outlet160and a waste water inlet110formed in the upper portion of the side thereof, so that hot waste water flows from the upper portion to the lower portion of the tank and city water flows from the lower portion to the upper portion of the tank.

As shown inFIG. 2, the heat exchange pipe500has a number of the city water flow pipes of the ‘S’ shape, which are welded one another, and the surface of the heat exchange pipe500has a plate type structure for increasing a heat exchange efficiency and providing an easy cleaning of the surface thereof. The heat exchange pipe500may have a heat exchange pin mounted on the surface thereof to increase a heat transferring area within the limit allowing the easy cleaning. The circulation leading plates200and the heat exchange pipes500are designed in such a manner to be smoothly assembled at a little space from the tank100and to easily discharge sewage after the cleaning. The tank inspection holes130formed in the side of the tank100allows a user to inspect the inside of the tank with naked eyes and to clean the tank from the outside with high pressure water or any cleaning tool. The tank inspection holes130may be formed all sides or upper or lower portions of the tank as occasion demands. Temperature sensors (not shown) are mounted on the city water inlet and outlet140and160and the waste water inlet and outlet110and120to inspect the driving condition of the waste heat recovery system.

The plate type circulation leading plates200shown inFIG. 3are mounted between the heat exchange pipes500of the ‘S’ shape for circulating waste water inside the tank in a zigzag form so as to transfer lots of heat to the city water of the heat exchange pipes as much as possible. The circulation leading plate200is a rectangular hollow box type, and includes the movable nozzle parts mounted on the upper and lower portions of the circulation leading plate200, reinforcing plates250mounted inside the circulation leading plate200at regular intervals for reinforcing the nozzle driving part driving the movable nozzles210and the circulation leading plate200, and through holes260formed in the reinforcing plates250for allowing easy installation and driving of the nozzle driving part and the movable nozzle part.

The movable nozzle part includes the movable nozzle210having a number of nozzle holes220formed in the upper portion thereof, a guide protrusion240formed on the lower surface of the movable nozzle210for guiding the movable nozzle onto the guide rail230formed on the circulation leading plate200, a soft high pressure water distribution pipe320for connecting the movable nozzle210and the rectangular channel310to induce high pressure water, and a high pressure water connector330for connecting the high pressure water distribution pipe320to the movable nozzle210. The movable nozzle210has a number of the nozzle holes220opposed to the surface of the heat exchange pipe500, so that the high pressure water can clean the external surface of the heat exchange pipe. It is preferable that the movable nozzle210, as shown inFIG. 3, has an arc-shaped edge formed on a side thereof so as to prevent damage of the edge of the movable nozzle when the high pressure water distribution pipe320moves together with the movable nozzle210. The high pressure water distribution pipe320has a length sufficient to move the movable nozzle on the guide rail.

As shown inFIG. 4, the nozzle driving part includes a driving shaft410connected with the driving motor400, and a driving wire430wound on the driving shaft a round and supported by a support roller420. When the driving shaft rotates, the driving wire430wound on the driving shaft is driven by frictional force between the driving wire430and the driving shaft, and thereby, the movable nozzle210connected with the driving wire is also moved. One driving shaft may have the driving wire and the support roller for supporting the driving wire to drive two movable nozzles210mounted on the upper and lower portions of the circulation leading plate200. In this case, the driving wires430can be mounted right and left sides of the driving shaft to prevent interference between the driving wires430. The movable nozzles210move along the guide rail230from a side of the circulation leading plate200to the other side thereof, and are returned to an original position as the rotational direction of the motor is changed by the sensing part when the movable nozzles210reach the other side of the circulation leading plate200.

The position sensing part mounted on the outer surface of the assembly plate170includes a sensing wire610wound on the driving shaft410a round like the nozzle driving part and supported by a support roller600, a movable body620mounted on the sensing wire610, and a limit switch630for sensing movement position of the movable body. When the driving shaft rotates, the sensing wire610wound on the driving shaft is also moved, and thereby, the movable body620connected with the sensing wire610is also moved. The movable body and the limit switch630are mounted in such a manner that the movable body620is in contact with the limit switch630when the nozzle driving part is arrived at right and left ends of the circulation leading plate200.

FIG. 5shows a structure of the heat exchange plate500. The heat exchange pipe500having a number of the city water flow pipes bound into one is connected to the city water inlet and outlet140and160and a hollow box type city water connecting part510. The city water connecting part510of the city water inlet140side has a flux control device520mounted therein so as to distribute city water inside the entire heat exchange pipe500. The flux control device520is hinged to an upper plate540of the city water connecting part by means of a plate type member530, and the lower portion of the plate type member530is heavier than the upper portion thereof and is mounted downwardly from a hinge shaft550by the self-weight. The plate type member530of the flux control device520is higher than the city water connecting part510and inclined somewhat against a perpendicular line.

Next, a driving process of the present invention will be described in detail. As shown inFIG. 2, in the upper portion of the tank, waste water is induced into the tank100through the waste water induction pipe110and transfers heat of the waste water to the heat exchange pipe500while flowing to the lower portion of the tank along the waste water path formed by the circulation leading plates200. The city water is induced from the lower portion of the tank through the city water inlet140and flows along the S-shaped heat exchange pipe500. The city water heated by heat of the waste water is discharged through the city water outlet160of the upper portion of the tank. The discharged city water is stored in a temporary storage tank (not shown) when additional heating is not needed, but transferred to a hot water boiler when additional heating is needed. The induced city water is distributed uniformly inside the entire heat exchange pipe500by means of the flux control device520of the city water inlet140side. The flux control device520closes a flow channel of the city water connecting part510by the weight of the plate type member530serving as a valve, and opens the flow channel while rotating on the hinge550due to hydraulic pressure of the city water. In this process, the plate type member530acts to distribute the city water uniformly in a width direction of the city water connecting part510.

The present invention senses temperature of the inflow and outflow city water by means of the temperature sensor mounted on the city water inlet and outlet during driving of the waste heat recovery system to determine whether or not heat recovery is carried out properly. If the heat recovery efficiency is less than the optimum value, the waste heat recovery system determines it that foreign matters are accumulated on the surface of the heat exchange pipe and cleans the surface of the heat exchange pipe. In general, a boiler system in a public bath and other boiler system do not need additional pump for generating high pressure as using high pressure water, but in case of boiler systems which do not use high pressure water, additional pump is mounted between the existing boiler system and the waste heat recovery system of the present invention. When the electronic valve340is opened by means of a controller to induce high pressure water into the circulation leading plates200, the high pressure water is induced into the rectangular channel310through the high pressure water induction pipe300, and the high pressure water is induced into each movable nozzle210through the high pressure water distribution pipe320and sprayed onto the surface of the heat exchange pipe. The high pressure water removes sewage stained on the surface of the heat exchange pipe500and discharged to a space between the heat exchange pipe500and the tank body. The high pressure water is discharged to the outside of the tank together with the waste water. If necessary, a sewage discharge hole is formed in the tank to discharge sewage to the outside of the tank.

Referring toFIGS. 3 and 4, the operation of the movable nozzle part will be described in detail. Each movable nozzle210is driven by the driving motor400and moves along the guide rail230of the circulation leading plate200, and at this time, the movable body620of the position sensing part is also moved in the same way as the movable nozzle210. When the movable nozzle210arrives at an end portion of a side of the circulation leading plate, the movable body contacts with the limit switch630located at a side of the movable body, and the controller inverts the rotational direction of the driving motor by a signal of the limit switch630. As a result, the movable nozzle returns to its original position, and the movable body moving in the same way as the movable nozzle210is in contact with the limit switch630of the other side of the movable body and transfers the signal to the controller. Thereby, the driving motor is stopped, and the electronic valve340is closed.

If one driving of the movable nozzle part cannot provide sufficient cleaning and heat recovery efficiency, the movable nozzle part carries out the cleaning of the heat exchange pipe several times. If the heat exchange pipe is not cleaned sufficiently even by the above method, as a subsidiary method, the user directly sprays high pressure water onto the surface of the heat exchange pipe by inserting a high pressure hose or other cleaning tool into the tank inspection holes130formed in the side surface of the tank.

If there is a need to replace the internal components or clean the inside of the waste heat recovery system due to a long term use of the waste heat recovery system, the screw coupling between the assembly plate170and the tank flange180formed at a side of the tank is unscrewed so as to separate the assembly plate170from the tank100, so that the user can easily replace the internal components or clean the inside of the tank.

FIG. 6shows a second preferred embodiment of the present invention. In the second preferred embodiment, the waste heat recovery system adopts a motor driving type nozzle driving part, differently from the first preferred embodiment, in which the wire driving type nozzle driving part having the driving motor, the driving wire and the pulleys. The motor driving type driving part shown inFIG. 6includes a driving motor700, a deceleration gear710connected with the driving motor700, a rotation sensor720for sensing rotational frequency of the driving motor700, and a power transferring part800for transferring driving power of the deceleration gear to each driving shaft740. The power transferring part800has pulleys810mounted on the driving shafts740and connected with the deceleration gear710by means of belts. The pulleys810are oppositely mounted so as to rotate the adjacent driving shafts in the opposite directions.

The nozzle driving part has the driving shafts740, which has an end connected with the pulley810, the other end connected with a driving shaft supporter750, and a screw thread for slidably moving the guide protrusion240. The guide protrusion240is connected with the two movable nozzles210mounted on the upper and lower portions of the circulation leading plate200.

The driving part shown inFIG. 6is mounted on the outer surface of the tank100to drive the movable nozzles210in a longitudinal direction of the circulation leading plate200. The driving motor700, the deceleration gear710and the power transferring part800can be installed in consideration of relationship between other components. Furthermore, the driving shafts740mounted on the adjacent circulation leading plates have opposed rotational directions due to the pulleys mounted oppositely. Therefore, one of the adjacent driving shafts has a right-hand screw and the other has a left-hand screw to drive the movable nozzles210mounted on different circulation leading plates200in the same direction. The shape of the reinforcing plate250or the internal structure of the circulation leading plate200in which the nozzle driving part is mounted can be changed to easily operate the guide protrusion240along the driving shaft740.

A driving process of the motor driving type waste heat recovery system as shown inFIG. 6will be described in detail. When the driving motors700drive, driving power transferred to each pulley810through the deceleration gear710, and thereby, the driving shafts740connected with the pulleys respectively are rotated. Thereby, the guide protrusions240coupled with the movable nozzles210slide on the driving shafts740. When the driving motors drive, the electronic valve330is opened by the controller, and high pressure water is induced into the movable nozzles210and sprayed onto the surface of the heat exchange pipe. The controller discriminates by means of the rotation sensor720whether or not the movable nozzles210arrive at the end portions of the sides of the circulation leading plates200, and change the rotational direction of the driving motors700. When the movable nozzles are returned to their original positions, the driving motors700stop the driving and the electronic valve is closed. The driving motors700, which are mounted on the circulation leading plates200respectively, are driven by one controller in the same way, and operate the movable nozzles210of the circulation leading plates200.

FIG. 7shows a third preferred embodiment of the present invention, which adopts a brush cleaning type waste heat recovery system for directly cleaning the surface of the heat exchange pipe by mounting a brush on each movable nozzle.

As shown inFIG. 7, a brush280is mounted on the upper surface of the movable nozzle210in such a manner not to stop the nozzle holes220. The brush280is in a direct contact with the surface of the heat exchange pipe500and operated in the longitudinal direction of the heat exchange pipe500to remove foreign matters stained on the surface of the heat exchange pipe. The movable nozzles having the brushes280can be adopted on both of the wire driving type waste heat recovery system shown inFIG. 4and the motor driving type waste heat recovery system shown inFIG. 6. This embodiment can adopt all of the high pressure water cleaning method for cleaning the surface of the heat exchange pipe with high pressure water and the brush cleaning method for cleaning the surface of the heat exchange pipe with the brush mounted on the movable nozzle.

FIG. 8shows a fourth preferred embodiment of the present invention adopting a brush cleaning type waste heat recovery system for cleaning the surface of the heat exchange pipe only with brushes mounted on the movable nozzles, from which components related with high pressure water mounted on the waste heat recovery systems according to the first to third preferred embodiments are all removed.

In the waste heat recovery system shown inFIG. 8, the high pressure induction pipe300, the rectangular channel310and the electronic valve340mounted on the outer surface of the waste heat recovery system are removed, the movable nozzle210of the movable nozzle part does not have a number of the nozzle holes220, and the soft high pressure water distribution pipe320for inducing the high pressure water and the high pressure water connector330for connecting the high pressure water distribution pipe320to the movable nozzle210are also removed.

Therefore, the waste heat recovery system shown inFIG. 8includes: a tank100; a number of heat exchange pipes500connected with one another in the form of a ‘S’ shape in multiple steps inside the tank100and having a number of city water flow pipes bound up into a bundle; circulation leading plates200mounted between the heat exchange pipes500to form waste water paths; a movable nozzle part mounted on the outer surface of the circulation leading plates200and having brushes280; a nozzle driving part mounted inside the circulation leading plates for driving the movable nozzle part along guide rails230formed on the circulation leading plates200; a driving part mounted on the outer surface of the tank lo for driving the nozzle driving part; and a position sensing part connected to the driving part to control a rotational direction of a driving motor using a position sensor for sensing position of the movable nozzle part.

The nozzle driving part can adopt the wire driving type of the first preferred embodiment or the motor driving type of the second preferred embodiment.

The brush cleaning type waste heat recovery system for cleaning the surface of the heat exchange pipe only with the brushes can provide a simple structure and an easy maintenance as not needing the components related with high pressure water.

The operation process of the brush cleaning type waste heat recovery system will be described. In the waste heat recovery system, the temperature sensors mounted on the city water inlet and outlet senses temperature of the inflow and outflow city water during the driving of the waste heat recovery system to determine whether or not heat recovery is carried out properly. If the heat recovery efficiency is less than the optimum value, the recovery system determines that foreign matters are accumulated on the surface of the heat exchange pipe, and operates the controller to clean the heat exchange pipe. The controller operates the driving motor400, and operates the movable nozzles210having the brushes to clean the surface of the heat exchange pipe. The rotation sensor720discriminates whether or not the movable nozzles210arrive at the ends of the circulation leading plates, and change the rotational direction of the driving motors. The controller controls the driving motors to repeat the above motion several times till the foreign matters formed on the surface of the heat exchange pipe500are removed, and after that, determines that the heat recovery efficiency is increased by measuring the temperature of the inflow and outflow city water.

FIG. 9shows a waste water distribution device for improving a flow of waste water. The waste water distribution device900serves to uniformly distribute the waste water induced from the upper portion of the waste heat recovery system to the whole heat exchange pipe500. For this, as shown inFIG. 9, the waste water distribution devices are installed at curved portions of the heat exchange pipe. The waste water distribution device900includes a plate type member910connected to the waste heat recovery system body by means of a hinge shaft920to distribute waste water in the width direction of the heat exchange pipe. A torsion spring is mounted on the hinge shaft920or a coil spring is mounted on the bottom surface of the plate type member910to prevent drooping of the plate type member910due to its self weight. The waste water distribution device having the above structure closes the flow channel of the waste water in normal times, but opens the flow channel by the rotation of the plate type member910on the hinge shaft920when waste water is flown in.

In the present invention, the waste heat recovery system has a packing mounted on the guide rail230of the circulation leading plate200, on which the movable nozzle210is moved, to prevent induction of sewage of waste water into the circulation leading plate. The packing can be mounted on the guide rail as there is an interval between the guide protrusion, which is connected with the movable nozzle and moves on the guide rail, and the guide rail. At this time, it is preferable the packing split at the center is used to make a gap when the guide protrusion is moved.

Moreover, in the present invention, other heat transferring fluid or heat transfer oil of high specific heat capacity for reducing corrosion of the pipe channel can be used in stead of city water. In addition, refrigerant can be used in stead of city water. The refrigerant, which passed an evaporator of a cooling system, passes the waste heat recovery system and preheated before being inserted into a compressor to reduce energy consumption of the compressor. Alternatively, the present invention can evaporate the refrigerant without energy consumption by the waste heat recovery system of the present invention serving as the evaporator of the cooling system.

INDUSTRIAL APPLICABILITY

As described above, the waste heat recovery system of the heat exchange method for recovering heat of water wasted from a public bath, a factory or a swimming pool can easily clean the heat exchange pipe, thereby increasing heat exchange efficiency and providing an easy maintenance. Therefore, the present invention can solve the problems of the existing heat exchange systems, such as decrease of heat exchange efficiency due to a long-term use and inconvenient maintenance.