JP2005221219A - Warm water type heating system and operation method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a warm water type heating system suitable for a system in which a radiating terminal is set in a higher position than a heat source machine, and an operation method thereof. <P>SOLUTION: In stopping the operation, the drive of a circulation pump 4 is stopped in response to a heating stop request from a floor heating panel 12 side, and subsequently a thermal valve 8 and a thermal valve 9 are simultaneously stopped to heat. Although both thermal valves start to close with stopping of heating, the wax capacity of the thermal valve 8 is smaller than that of the thermal valve 9 so that its valve closing speed is higher and the valve is totally closed at the time T5. On the other hand, the thermal valve 9 is totally closed at the time T6. Thus, the thermal valve 9 of a return circuit 7 opened to the atmosphere is totally closed later, so that an increase in internal pressure of the pipe due to cooling of the pipe can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hot water heating system that circulates hot water through a hot water pipe and an operation method thereof, and more particularly to a hot water heating system suitable for a system including a heat radiating terminal that is installed at a higher position than a heat source device and an operation method thereof. About.

In a hot water heating system that circulates hot water through a hot water pipe, a phenomenon occurs in which air enters the pipe due to various causes and stays in the circulation path over time. As a result, when an open cistern (expansion tank), which is an open location, is installed at a lower position than the heat radiating terminal, there is a problem that the water in the pipe “drops” and overflows from the cistern. In order to prevent this, a method has been proposed in which the air staying in the piping is removed by forcibly circulating the water in the hot water piping by periodically driving a circulation pump (for example, actual open-air 5). -83617). However, in this method, the operation must be performed even when air is not retained in the pipe. Also, when the air bleeding operation and the heating operation overlap, the heat radiation terminal in a room that is not subject to heating is also used. The inconvenience that hot water circulates arises.
Japanese Utility Model Publication No. 5-83617

  In order to solve this problem, in addition to the shut-off valve (thermal valve) usually installed in the outgoing circuit of the hot water circulation circuit, a shut-off valve is also installed in the return circuit (upstream of the circulation pump). Thus, it is conceivable to prevent “water drop” by closing both shut-off valves when the operation is stopped. FIG. 13 shows an example of such a hot water heating system. In the figure, the circulation circuit of the hot water heating system 100 includes a heat source unit 101, an open-type cistern 108 built in the heat source unit, a circulation pump 104, a heat exchanger 105 that receives heat from combustion of a burner (not shown), It is composed of a floor heating panel 102 as a heating terminal installed at a higher position than the heat source unit 101, a forward side circuit 103 and a return side circuit 104 connecting the heat source unit 101 and the floor heating panel 102. A cross-linked polyethylene pipe (PE pipe) is used as the piping material for the forward side circuit 103 and the return side circuit 104. Stop valves 106 and 107 are provided in the middle of the forward circuit 103 and the return circuit 104, respectively. The piping constituting these circulation circuits is filled with hot water, and the open expansion tank 108 is configured to always store hot water 109.

  In such a system, if the shutoff valves 106 and 107 are closed when the operation is stopped, there is a problem that high pressure is applied to the piping due to thermal contraction of the piping over time.

  The present invention is for solving such a problem, and even in the case where a shut-off valve (thermal valve) is installed on the upstream side of the circulation pump, the pressure in the pipe is increased by the thermal contraction of the resin pipe. The technique which avoids is provided.

  The gist of the present invention is as follows. That is,

  (1) A circulation circuit having a heat source unit, one or a plurality of heat radiation terminals, one or a plurality of forward and return circuits connecting the heat source unit and each heat radiation terminal by piping, and an open type in the circulation circuit A hot water heating system having a systern, a circulation pump, and one or more forward stop valves and return stop valves in the forward circuit and the return circuit, respectively, and prevents an increase in the internal pressure of the pipe when the operation is stopped A hot water heating system comprising a pressure rise prevention means in a circulation circuit.

  By providing the “pressure rise prevention means” in the circulation circuit, it is possible to prevent the internal pressure of the pipe from rising even if the both shut-off valves are closed when the operation is stopped.

  As the “closing valve”, a thermally operated valve, an electromagnetic valve, or the like can be used.

  As the “heat radiating terminal”, a hot water heating terminal such as a floor heating panel or a fan convector can be used.

  (2) The forward side circuit and the return side circuit each include a collecting pipe part and a plurality of branch pipe parts branched from the collecting pipe part to reach each heat radiating terminal, and the return side stop valve (1) The hot water heating system according to (1), characterized in that it is provided in a collective piping section of a return side circuit, and the forward stop valve is provided in each branch piping section of the forward circuit.

  The present invention is an effective system particularly when a plurality of heat dissipating terminals are connected by the header method. According to the present invention, even when a plurality of heat dissipating terminals are individually operated as described later, it is possible to prevent an increase in the internal pressure of the pipe when the operation is stopped.

  Further, according to the present invention, the power supply of the forward stop valve can be branched from the same terminal portion without providing a new terminal block, so that cost reduction and space saving can be achieved.

  (3) (1) or (2), wherein the pressure rise prevention means includes a sealed expansion tank disposed upstream of the return-side shut-off valve in the circulation circuit. Hot water heating system.

  A closed expansion tank can be used as the “pressure rise prevention means”. As the closed expansion tank, for example, a diaphragm type tank can be used. The installation position of the sealed expansion tank may be any of a forward circuit, a heating terminal unit, and a return circuit.

  (4) The pressure rise prevention means starts the circulation pump after opening the return side closing valve when starting operation, and closes the return side closing valve after stopping the circulation pump when stopping operation. The hot water heating system according to any one of (1) to (3), characterized in that it comprises means.

  By closing the return-side stop valve after the circulation pump is stopped, the pressure inside the circulation pump is released, so that the internal pressure of the pipe does not increase. The stop time difference between the circulation pump and the return-side stop valve can be determined in consideration of the degree of pipe heat shrinkage accompanying cooling.

  (5) The pressure rise prevention means opens the return-side shutoff valve after opening the return-side shutoff valve at the start of operation, and opens the forward-side shutoff valve when the operation is stopped. The hot water heating system according to any one of (1) to (3), further comprising means for closing the return-side stop valve later.

  (6) The hot-water heating system according to any one of (1) to (5), wherein the forward-side shut-off valve and the return-side shut-off valve are a forward-side thermal valve and a return-side thermal valve, respectively.

  The thermal valve is widely used as a shut-off valve for a hot water heating system, and the speed of the opening / closing valve can be easily controlled by changing the specification of the expansion agent of the thermal valve as described later. It is extremely effective as a “control means”.

  (7) The return side thermal valve has a heat capacity of the encapsulated expansion agent smaller than that of the expansion agent enclosed in the forward side thermal valve, and has a heating capacity of the forward side thermal valve. The hot water heating system according to (6), which is larger than the heating capacity.

  The time required for closing is controlled by making the heat capacity and heating capacity of the expansion agent (for example, wax) enclosed in the thermal valve different between the forward side thermal valve and the return side thermal valve as in the present invention. As described later, it can function as a pressure rise prevention means. Specifically, it can also be realized by installing a thermal valve that is difficult to cool by increasing the amount of wax on the return side so that it closes late. Further, in this case, the return side thermal valve can be opened earlier at the start of operation by making the heater capability of the return side thermal valve larger than that of the forward side thermal valve.

  (8) The hot water heating system according to (6), wherein the return-side thermal valve has a larger thermal expansion coefficient than the forward-side thermal valve.

  This can also be realized by reducing the coefficient of thermal expansion of the wax used for the return side thermal valve so that it does not shrink easily and closing the return side late. Further, in this case, the return side thermal valve can be opened quickly at the start of operation by making the heater capacity larger than the forward side thermal valve.

  (9) The pressure rise prevention means includes a bypass circuit that bypasses the return-side stop valve, and an overpressure relief valve provided in the bypass circuit (1), ( 2) The hot water heating system according to (4) to (8).

  As the “pressure rise prevention means”, a configuration in which an overpressure relief valve is installed in a bypass circuit that bypasses the return-side stop valve can be used. As a result, when the internal pressure of the pipe becomes a certain value or more, the bypass circuit bypasses the hot water and returns to the systern, thereby reducing the internal pipe pressure.

  (10) In the hot water heating system according to the above (5) or (6), the return-side stop valve is opened earlier than the forward-side stop valve of the heating target system at the start of operation, and the operation is stopped when the operation is stopped. A method for operating a hot water heating system, wherein the return side closing valve is closed later than the forward side closing valve.

  (11) In the hot water heating system according to the above (5) or (6), at the start of operation of one or a plurality of heating target systems, after the return-side stop valve of the collective piping section is opened, the one or The return-side shut-off valve of the collective piping section after opening the forward-side shut-off valve of the plurality of heating target systems and closing the forward-side shut-off valve of the one or more heating target systems when the operation is stopped The operation method of the hot water type heating system characterized by closing valve.

  (12) A heat circuit, one or a plurality of heat radiating terminals, a circulation circuit having one or a plurality of forward and return circuits connecting the heat source machine and each heat radiating terminal by piping, and an open type in the circulation circuit A hot water heating system comprising a systern, a circulation pump, and one or more forward stop valves and return stop valves in the forward circuit and the return circuit, respectively, and pipe pressure is set when operation is stopped A hot water heating system comprising pressure maintaining means for maintaining a pressure lower than a withstand pressure value.

  While the inventions of the above (1) to (11) prevent the increase in the internal pressure of the pipe by shifting the closing time of the both stop valves when the operation is stopped, in the present invention, in the pipe after the both stop valves are closed. The object is achieved by maintaining the pressure at a pressure lower than the piping withstand pressure value. By such means, it is possible to prevent the occurrence of negative pressure in the pipe due to, for example, oxygen permeation through the resin pipe or slight leakage from the connecting portion.

  As the “pipe pressure value”, an appropriate value can be adopted depending on the pipe material to be used.

  (13) The hot water heating system according to (12), characterized in that the pressure maintaining means includes means for continuously operating the circulation pump for a time until the pressure reaches a pressure lower than the piping withstand pressure value when the operation is stopped. .

  (14) In the hot water heating system according to the above (12) or (13), when the operation is stopped, the return-side stop valve is closed, the circulation pump is operated for a predetermined time, and then the circulation pump is stopped. A method of operating a hot water heating system, wherein the forward side closing valve is closed.

  As the “pressure maintaining means”, a method in which the circulation pump is operated for a predetermined time to pressurize can be used.

  (15) The hot water heating system according to (1) or (2), wherein the pressure rise prevention means includes a check valve disposed in the return side circuit.

  As the “pressure rise prevention means”, a check valve disposed in the return side circuit can be used. In this case, it is necessary to select the valve opening pressure of the check valve in consideration of the pressure applied to the check valve when the circulation pump is driven, as will be described later.

  (16) The hot water heating system according to any one of (1) to (15), wherein one or a plurality of the heat radiating terminals are installed at a higher position than the open systern. .

  When the open system turn, which is an open part, is installed at a lower position than the heat radiating terminal, the above-mentioned inventions are particularly effective because “water drop” due to negative pipe pressure is likely to occur as described above.

  (17) The hot water heating system according to any one of (1) to (16), wherein the branch pipe portion is piped with a resin pipe.

Each of the above inventions is particularly effective when a resin pipe is used for the branch pipe portion. Resin pipes have a lower pressure resistance than metal pipes and are easily affected by an increase in the internal pressure of the pipe. Therefore, according to the above inventions, it is particularly required to “prevent pressure rise” or “maintain pressure below the pressure resistance”.
(18) The pressure rise prevention means includes a return-side stop valve provided on the upstream side of the return-side header, an overpressure relief valve having an overpressure drain provided on the upstream side, the overpressure drain, The hot water heating system according to any one of (1), (2), (4) to (8), characterized in that it includes an escape pipe connecting the return side header.

  The present invention is characterized in that an overpressure relief valve is connected in series with a return side shut-off valve upstream of the return side header, and an overpressure drain of the overpressure relief valve is connected to the return side header. In addition, the overpressure relief valve in the present invention is opened when the pressure is lower than the operating pressure, the hot water flows downstream, and is closed when the pressure is higher than the operating pressure, and the hot water is released from the overpressure drain side through the piping to the return header. Operates as led. With such a configuration, an increase in pressure at the time of operation stop is suppressed, and it is possible to return to a cistern without discharging waste water during pressurization to the outside.

  In addition, according to the present invention, only the necessary system needs to be provided with a return-side stop valve and an overpressure relief valve. It can also be attached. Furthermore, since an overpressure relief valve and a shut-off valve are installed upstream of the return header, application to an existing system is facilitated.

  Unlike conventional systems, the above-described inventions can avoid the risk that the internal pressure of the pipe will rise above the pressure resistance of the pipe.

  According to the invention of claim 12 and below, the amount of air penetrating the pipe can be reduced by maintaining the internal pressure of the pipe within the pressure resistance value of the pipe.

  Further, according to the invention of claim 2 and the like, it is possible to realize cost reduction and space saving of the system.

  Hereinafter, an embodiment of a hot water heating system according to the present invention will be described in more detail with reference to FIGS. In addition, in order to avoid duplication, in each figure, the same structure is shown using the same code | symbol. Needless to say, the scope of the present invention is described in the claims and is not limited to the following embodiments.

(First embodiment)
FIG. 1 shows an overall configuration of a hot water heating system 1 according to a first embodiment of the present invention. In the figure, a hot water heating system 1 includes a heat source device 2, an open-type cistern 3 built in the heat source device 2, a circulation pump 4, and a heat exchanger 5 that transfers heat from combustion gas to a heat medium (water). And a circulation circuit constituted by a floor heating panel 12, which is a heating terminal, a forward circuit 6 connecting the heat source device 2 and the floor heating panel 12, and a return circuit 7. The piping of the circulation circuit is filled with water (or hot water) and is circulated in the circulation circuit by the circulation pump 4. The cistern 3 is a buffer tank against the expansion of hot water in the pipe accompanying the heating operation, and is configured to be drained to the outside through an overflow pipe (not shown) when rising above a predetermined water level.

  A cross-linked polyethylene pipe (PE pipe) is used as a piping material for the forward circuit 6 and the return circuit 7. In each path of the forward circuit 6 and the return circuit 7, thermal valves 8 and 9 are provided as closing valves. The heat source device 2 includes a control unit (not shown) inside, and based on requests from the floor heating panel 12 side, combustion, driving and stopping of the circulation pump 4, and opening of the thermal valves 8 and 9 It is configured to instruct system operation control such as valve closing.

  FIG. 6 shows a cross-sectional structure of the forward-side heat operated valve 8 used in the hot water heating system 1. The main body 61 of the thermal valve 8 mainly includes a hot water inflow portion 61a, a cylinder portion 61b, a hot water outflow portion 61c, a hot water inflow port 61d, and a heating portion 62. The piston part 63 which has the warm water outflow hole 63a is stored in the cylinder part 61b. A wax chamber 66 is provided in the warm water inflow portion 61a, and a wax 67 and a valve seat 65, which are expansion agents, are stored therein. The valve seat 65 and the piston portion 63 are connected by a shaft 64, and are configured to open and close the valve. The heating unit 62 includes a heater 62a and a power supply line 62b, and is configured to receive power from a power source (not shown) and to energize the heater 62a to heat the wax 67. The hot water flows from the hot water inlet 61d and is configured to flow downstream via the hot water inlet 61a, the hot water outlet hole 63a, and the hot water inlet 61d.

  Here, FIG. 6A shows a state when the valve is closed, and FIG. 6B shows a state when the valve is opened. That is, in FIG. 6A, the heater 62a is in a non-energized state, and the wax 67 is cooled, so the volume is small. For this reason, the piston part 63 is in a state of being accommodated in the cylinder part 61b, and the hot water does not flow out from the hot water outflow hole 63a. On the other hand, in FIG. 6A, the heater 62a is energized, the wax 67 is heated and expanded, the valve seat 65 is lifted upward, and the piston part 63 is lifted above the cylinder part 61b. The warm water flows out to the warm water outflow portion 61c through the warm water outflow hole 63a.

  The structure of the return-side thermal valve 9 is the same as that of the forward-side thermal valve 8, except that the heat capacity of the encapsulated expansion agent is smaller than that of the forward-side thermal valve, and the heating capacity of the heater is large. Thereby, a time difference can be provided in the valve opening / closing speed with respect to the return side. The power supply lines of the thermal valves 8 and 9 are branched from the same terminal of a terminal block (not shown).

  Next, with reference also to FIG. 5, the operation | movement of each part and the fluctuation | variation of the pressure in piping at the time of the operation | movement start of the hot water type heating system 1 and an operation stop are demonstrated. FIG. 5 shows temporal transitions of the valve openings of the thermal valve 8 and the thermal valve 9 during the period from the start of operation to the stop of operation. Actually, it is a curve depending on the opening characteristic of the valve, but here it is schematically shown as a straight line. In addition, the following operation | movement is performed based on the instruction | indication from the above-mentioned control part.

  In response to a heating start request from the floor heating panel 12 side, the thermal valve 8 and the thermal valve 9 start opening simultaneously. When the opening of both heat valves starts, the circulation pump 4 starts to drive, and the water in the pipe circulates in the circulation circuit. Then, combustion starts. The heat medium (water) in the pipe receives heat from the heat exchanger 5 and is heated to a predetermined temperature, and is supplied to the floor heating panel 12 as hot water.

  The time transition of the valve opening of the thermal valve 8 and the thermal valve 9 during this time is as follows. The thermal valve 8 and the thermal valve 9 start to open at the same time at T1, which is the operation start time. However, since the heating capacity of the thermal valve 9 is larger than the heating capacity of the thermal valve 8, the valve opening speed is fast. Fully open at T2. On the other hand, the thermal valve 8 is fully opened at time T3. Thus, since the valve opening speed of the thermal valve 9 on the atmosphere opening side is fast, the pressure is released, and a sudden increase in the internal pressure of the pipe accompanying the driving of the circulation pump 4 can be avoided.

  Next, when the operation is stopped, the circulation pump 4 stops driving in response to a heating stop request from the floor heating panel 12 side, and then the heat valve 8 and the heat valve 9 are heated and stopped simultaneously. At this time, the temporal transitions of the valve openings of the thermal valves 8 and 9 are as follows. That is, both heat valves start closing when heating is stopped, but the wax volume of the heat valve 8 is smaller than that of the heat valve 9, so that the valve closing speed is high and the valve is fully closed at time T5. On the other hand, the thermal valve 9 is fully closed at time T6. As described above, since the thermal valve 9 of the return side circuit 7 that is open to the atmosphere is late and fully closed, it is possible to prevent an increase in the pressure in the pipe accompanying the cooling of the pipe.

  In the present embodiment, a method of avoiding a pressure increase by making the valve opening speed and the valve closing speed different by appropriately selecting the heating speed and the wax volume of both the heat operated valves is not limited thereto, It is possible to cope with this problem by appropriately selecting the wax heat capacity and the coefficient of thermal expansion of both the heat operated valves.

(Second embodiment)
FIG. 2 shows an overall configuration of a hot water heating system 20 according to the second embodiment of the present invention. The hot water heating system 20 is different from the hot water heating system 1 according to the first embodiment in that the hot water heating system 20 includes a sealed expansion tank 21 in the circulation path. Furthermore, the opening and closing speeds of the outward-side thermal valve 22 and the return-side thermal valve 23 are the same. Since other configurations are the same as those of the first embodiment, the description thereof is omitted. The inside of the closed expansion tank 21 is divided into an N ₂ gas chamber 21b and a hot water chamber 21c through which hot water in the pipe is guided through the diaphragm 21a. When the hot water pressure rises, the diaphragm 21a is pushed up to increase the pressure. The rise is absorbed.

  Next, changes in valve operation and piping internal pressure when the hot water heating system 20 is started and stopped will be described. At the start of operation, the thermal valves 22 and 23 are simultaneously opened in response to a heating start request from the floor heating panel 12 side. Next, the circulation pump 4 is driven and the heat medium (water) circulates in the circulation circuit. Further, combustion is started, the heat medium in the circulation circuit is warmed to become hot water, and is supplied to the floor heating panel 12.

  When the operation is stopped, the circulation pump 4 stops driving in response to a heating stop request from the floor heating panel 12 side, and then the thermal valves 8 and 9 are closed. After the operation is stopped, the PE pipe shrinks with time and the pressure in the pipe gradually increases, but the pressure increase is suppressed by the buffer function of the sealed expansion tank 21. Thereby, the pressure in the piping can be suppressed to within the allowable pressure.

  In this embodiment, the speeds of opening and closing of the outward-side thermal valve 22 and the return-side thermal valve 23 are the same. However, the present invention is not limited to this. The opening / closing valve speed may be different.

(Third embodiment)
FIG. 3 shows a configuration of a hot water heating system 30 according to the third embodiment of the present invention. This embodiment differs from the second embodiment in that in this embodiment, a bypass circuit 31 and an overpressure relief valve 32 that bypass the return side thermal valve 9 are provided instead of the sealed expansion tank 21. It is. Other configurations are the same as those of the second embodiment. The overpressure relief valve 22 opens when the pipe internal pressure exceeds a predetermined pressure, and has a function of suppressing the pressure rise by flowing warm water downstream.

  Next, the operation of each part of the hot water heating system 20 and the fluctuations in the piping internal pressure will be described. About operation | movement at the time of a driving | operation start, since it is substantially the same as 1st embodiment, description is abbreviate | omitted. At this time, the overpressure relief valve 32 is closed.

  When the operation is stopped, the circulation pump 4 stops driving in response to a heating stop request from the floor heating panel 12 side, and then the thermal valves 8 and 9 are closed. After the operation is stopped, the PE pipe thermally contracts with time, and the pressure in the pipe gradually increases. At this time, when the internal pressure of the pipe reaches the set pressure of the overpressure relief valve 32, the valve is opened, and the hot water in the return side circuit 7 is guided to the open system 3 via the bypass circuit 31. Thereby, it can suppress that the pressure in piping exceeds an allowable pressure.

(Fourth embodiment)
FIG. 4 shows an overall configuration of a hot water heating system 40 according to the fourth embodiment of the present invention. The present embodiment is different from the above-described embodiments in that the present embodiment is provided with two floor heating panels (terminals A and B in the figure) instead of one as a heating terminal. In addition, the circulation circuit is divided into a collecting pipe part and a branch pipe part. That is, the forward side system is divided into the branch piping parts L1 and L2 from the collective piping part L5 via the header H1, and further led to the floor heating panels A and B ahead. The return side system is led from the floor heating panels A and B through the branch piping portions L3 and L4 to the collective piping portion L6 by the header H2, and further returns to the systern 3 in the heat source unit 2. Further, the outwardly operated thermal valves V1 and V2 are provided in the branch piping parts L1 and L2, respectively, and the return thermal valve V3 is provided in the collective piping part L6. Other configurations are the same as those of the first embodiment.

  Next, with reference also to the flowchart of FIG. 7, an example of each part operation | movement at the time of the operation start in this embodiment and the time of an operation stop is demonstrated. In the following operation example, at the start of operation, terminal A operates first, and terminal B operates during operation of terminal A. When the operation is stopped, a pattern is assumed in which the terminal A stops operating first, and then the terminal B stops operating.

  Along with the start of operation control, it is determined whether there is an operation request from any terminal (step S101). When the operation request is detected from the terminal A, the return side thermal valve V3 is first opened (step S102). Next, the forward side thermal valve V1 installed in the branch pipe portion L1 is opened (step S103).

  During the operation of the terminal A, it is continuously determined whether or not there is an operation stop request (step S104), and when the operation stop request is detected, the process skips to the steps described later (* 1). If there is no operation stop request, it is further determined whether there is an operation request from another terminal (terminal B) (step S105). If not, the monitoring in step S104 is continued (step S112). When there is an operation request from the terminal B, the thermal valve V2 is opened (step S106).

  Next, during operation of both terminals, it is monitored whether there is an operation stop request from either terminal (step S107), and when there is no operation stop request, monitoring is continued (step S112). When an operation stop request is issued from any terminal (terminal A in this embodiment), the thermal valve V1 is closed (step S108).

  Further, it is determined whether or not there is an operation stop request from another terminal (terminal B) that is in operation (step S109). When there is an operation stop request, the thermal valve V2 is closed (step S110). After all the outward-side thermal valves are closed, the return-side thermal valve V3 is closed (step S111).

  In this embodiment, although the example of 2 systems was shown as a heating terminal, it can control similarly not only in this but in the case of multiple systems. That is, at the start of operation, the closing valve installed in the collective piping section is opened first, and then the closing valve of each terminal installed in the branch piping section is opened. On the contrary, at the start of operation, all the shut-off valves on the collective piping section are closed after all the forward-side shut-off valves are closed. Such a flow can prevent the pressure in the pipe from exceeding the allowable pressure.

(Fifth embodiment)
Further, another embodiment of the present invention will be described. Since the configuration of this embodiment is the same as that of the above-described fourth embodiment, it will be described with reference to FIG. This embodiment is different from the fourth embodiment in that all terminals stop operating and the circulation pump 4 is driven after the return side thermal valve is closed to pressurize the inside of the piping system within a range not exceeding the allowable pressure. That is.

  FIG. 8 shows an operation flow based on this embodiment. In the figure, Steps S201 to S208 are the same as Steps S101 to S108 of the fourth embodiment, and thus description thereof is omitted. Hereinafter, the added steps will be described.

  After the terminal A's outward-side thermal valve V1 is closed, it is determined whether there is a request for stopping operation from another terminal (terminal B) that is still operating (step S209). When there is an operation stop request, the return-side thermal valve V3 is closed (step S210). Next, the circulation pump 4 is driven for a predetermined time (step S211). At this time, since the forward side thermal valve V2 is opened and the return side thermal valve V3 is closed, the circulation path is pressurized as the circulation pump 4 is driven. In this case, the drive time of the circulation pump 4 is set so that the pressurization by the drive of the circulation pump 4 becomes a predetermined pressure within the pipe allowable pressure. After the circulation pump 4 is stopped, the thermal valve V2 is closed (step S210). This makes it possible to maintain the inside of the circulation path at a predetermined internal pressure.

  In the present embodiment, the pipe pressure is managed based on the driving time of the circulation pump 4. However, the present invention is not limited to this, and other systems, for example, a system that maintains the allowable pressure by detecting the pipe pressure can also be adopted. .

  In this embodiment, the speeds of opening and closing of the outward-side thermal valve 22 and the return-side thermal valve 23 are the same. However, the present invention is not limited to this. The opening / closing valve speed may be different.

(Sixth embodiment)
FIG. 9 shows an overall configuration of a hot water heating system 50 according to the sixth embodiment of the present invention. The hot water heating system 50 is different from the hot water heating system 1 according to the first embodiment in that the hot water heating system 50 includes a check valve 51 instead of a thermally operated valve as a return side stop valve. It is. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

FIG. 10 shows the structure and operation of the check valve 51. The check valve 51 is provided in the middle of the return side circuit 7 and includes a valve seat 54, a valve 53, a spring 52, and a stopper 55. Here, (a) shows a state when the valve is closed, and (b) shows a state when the valve is opened. Since the pressure is not applied to the valve 53 when the circulation pump 4 is not driven, the valve 53 is pressed against the valve seat 54 by the force of the spring 52 as shown in FIG. When the circulation pump 4 is driven, the force of the spring 52 is overcome as shown in FIG. 10B, the valve 53 is opened, and hot water flows. The valve opening pressure P ₀ of the check valve 51 is set to satisfy P ₁ > P ₀ > P ₂ . Here, P1 is the pressure applied to the check valve 51 when the circulation pump 4 is driven, P2 is the head pressure of the floor heating panel 12 piping at a high place, and P1 = circulation pump discharge pressure + P2—piping resistance. Therefore, when the floor heating panel 12 is installed at a height of 10 m, P ₀ ≈100 kPa may be set.

  Next, changes in valve operation and piping internal pressure at the start and stop of operation of the hot water heating system 50 will be described. At the start of operation, the thermal valve 8 is opened in response to a heating start request from the floor heating panel 12 side, and then the circulation pump 4 is driven to circulate the heat medium (water) in the circulation circuit. As a result, the pipe internal pressure becomes equal to or higher than the valve opening pressure of the check valve 51, so that the valve is opened (the state shown in FIG. 10B). When the operation is stopped, the circulation pump 4 stops driving in response to a heating stop request from the floor heating panel 12 side, and then the thermal valve 8 is closed. Further, the check valve 51 is also closed due to a drop in the internal pressure of the piping accompanying the stoppage of the circulation pump 4 (state shown in FIG. 10A).

After the operation is stopped, the pressure in the pipe gradually increases with time due to the heat shrinkage of the PE pipe, but when the pressure in the pipe exceeds P ₀ , the check valve 51 is opened and the pressure rise is suppressed. Thereby, the pressure in the piping can be suppressed to within the allowable pressure.
(Seventh embodiment)
FIG. 11 shows a configuration of a hot water heating system 60 according to the seventh embodiment of the present invention. FIG. 12 is a view showing a closed state (FIG. 12A) and an opened state (FIG. 12B) of the overpressure relief valve 61 having the overpressure drain port 62. This embodiment is the same as the fourth embodiment (see FIG. 4) in that it includes two floor heating panels (terminals C and D in the figure) that are heating terminals. The same applies to the point that the circulation circuit is divided into a collecting pipe part and a branch pipe part. The forward side system is divided into the branch piping parts L1 and L2 from the collective piping part L5 via the header H1, and further led to the terminals (floor heating panels) C and D, respectively. The same applies to the points where V1 and V2 are provided in the branch pipe portions L1 and L2, respectively.

The difference from the above-described fourth embodiment is that, in the fourth embodiment, the shutoff valve V3 is arranged downstream of the header H2 of the return side system, whereas in this embodiment, “water drop” is caused. For a system that may be in danger, an overpressure relief valve is connected in series with a shut-off valve upstream of the header. That is, in this embodiment, it is assumed that the terminal C is installed on the second floor and the terminal D is installed on the first floor, and an overpressure relief valve is installed for the terminal C system that is likely to “drop water”. Specifically, for the return side system of the terminal C, an overpressure relief valve 61 and a stop valve V4 are connected in series upstream of the header H3. Further, the overpressure drain 62 of the overpressure relief valve 61 and the header H3 are connected by a relief pipe L7.
As a result, the hot water leaving the terminal C is guided to the header H3 via the branch pipe portion L3, the overpressure relief valve 61, and the closing valve V4, and further returns to the systern 3 via the collective piping portion L6. On the other hand, the terminal D system is not provided with an overpressure relief valve and a stop valve. For this reason, the hot water is directly led to the header H3 through the branch pipe portion L4 and returns to the systern 3 through the collective pipe portion L6.

  In the present embodiment, the overpressure relief valve 61 has the valve body 63 pressed against the valve seat 65 by the spring 64 below the operating pressure, so that warm water passes downstream (FIG. 12A). The body 63 overcomes the reaction force of the spring 64 and moves away from the valve seat 65, and guides the hot water to the header H3 via the overpressure drain 62 and the escape pipe L7 (FIG. 12 (b)). That is, since the pressure is lower than the operating pressure of the overpressure relief valve 61 during the terminal operation, the hot water flows toward the closing valve V4. When the shutoff valve V4 is closed due to the operation stop, the internal pressure of the pipe rises. When the operating pressure of the overpressure relief valve 61 is exceeded, the hot water is guided to the header H3 not via the shutoff valve V4 but via the relief pipe L7. Further, the system returns to the systurn 3 through the collective piping portion L6. Thereby, a pressure rise is suppressed.

  In this embodiment, although the example of two systems was shown as a heating terminal, it is not restricted to this, and also in the case of a multi-system, it is the same. In addition, the same control as in the fourth embodiment is possible for the open / close control of the stop valve.

  INDUSTRIAL APPLICABILITY The present invention can be widely used in a hot water heating system that circulates hot water through hot water piping.

It is a figure showing warm water type heating system 1 concerning a first embodiment of the present invention. It is a figure which shows the hot water type heating system 20 which concerns on 2nd embodiment of this invention. It is a figure which shows the hot water type heating system 30 which concerns on 3rd embodiment of this invention. It is a figure which shows the hot water type heating system 40 which concerns on 4th embodiment of this invention. It shows the time transition of the valve opening degree of the forward side thermal valve and the return side thermal valve during the period from the start to the shutdown. It is sectional drawing which shows the state at the time of valve closing of a thermally operated valve. It is a figure which shows the flow of each part operation | movement from a driving | operation start in 4th embodiment to a stop. It is a figure which shows the flow of each part operation | movement from the operation start to a stop in 5th embodiment. It is a figure which shows the hot water type heating system 50 which concerns on 6th embodiment of this invention. It is a figure which shows the structure and effect | action of a check valve. It is a figure which shows the structure of the hot water type heating system 60 which concerns on 7th embodiment of this invention. It is a figure which shows the overpressure relief valve. It is a figure which shows the conventional warm water type heating system.

Explanation of symbols

1, 20, 30, 40, 50, 60 ... Hot water heating system 2 ... Heat source machine 3 ... Open-type systern 4 ... Circulation pump 5 ... Heat exchanger 8 , 22 ··· Outward side thermal valve 9, 23 ··· Return side thermal valve 12 ··· Floor heating panel
32, 61 ... Overpressure relief valve 21 ... Sealed expansion tank 31 ... Bypass circuit 51 ... Check valve

Claims (18)

A circulation circuit having a heat source unit and one or more heat radiating terminals, one or a plurality of forward circuit and return circuit connecting the heat source device and each heat radiating terminal with a pipe, and an open systern and circulation in the circulation circuit A hot water heating system comprising a pump and one or more forward stop valves and return stop valves in the forward circuit and the return circuit, respectively.
A hot water heating system, characterized in that the circulation circuit is provided with pressure increase prevention means for preventing an increase in the internal pressure of the pipe when the operation is stopped. The forward-side circuit and the return-side circuit each include a collecting pipe part and a plurality of branch pipe parts branched from the collecting pipe part to reach each heat radiating terminal, and the return-side stop valve is connected to the return-side circuit. 2. The hot water heating system according to claim 1, wherein the forward-side stop valve is provided in each branch pipe portion of the forward-side circuit. 3. The hot water heating system according to claim 1, wherein the pressure rise prevention means includes a hermetic expansion tank disposed upstream of the return-side shut-off valve in the circulation circuit. . The pressure rise prevention means includes means for starting the circulation pump after opening the return side shut-off valve when starting operation, and closing the return side stop valve after stopping the circulation pump when stopping operation. The hot water heating system according to any one of claims 1 to 3, wherein The pressure rise prevention means opens the return-side stop valve after opening the return-side stop valve at the start of operation, and opens the return-side stop valve after closing the forward-side close valve when the operation is stopped. 4. The hot water heating system according to claim 1, further comprising means for closing the side stop valve. The hot-water heating system according to any one of claims 1 to 5, wherein the forward-side closing valve and the return-side closing valve are an outward-side thermal valve and a return-side thermal valve, respectively. The return-side thermal valve has a heat capacity of the encapsulated expansion agent that is smaller than the heat capacity of the expansion agent enclosed in the forward-side thermal valve, and has a heating capacity that is greater than the heating capacity of the forward-side thermal valve. The hot water heating system according to claim 6, wherein the hot water heating system is large. The hot water heating system according to claim 6, wherein the return side thermal valve has a larger coefficient of thermal expansion than the forward side thermal valve. 9. The pressure increase preventing means includes a bypass circuit that bypasses the return-side stop valve, and an overpressure relief valve provided in the bypass circuit. The hot water heating system described. The hot water heating system according to claim 5 or 6, wherein when the operation is started, the return side stop valve is opened earlier than the forward side stop valve of the heating target system, and when the operation is stopped, the return side stop valve is opened. A method of operating a hot water heating system, characterized in that the valve is closed later than the forward side stop valve. The hot water heating system according to claim 5 or 6, wherein when the operation of one or more heating target systems is started, the return side shut-off valve of the collective piping section is opened and then the one or more heating target systems are moved forward. Opening the shut-off valve and closing the return-side shut-off valve of the collective piping section after closing the forward-side shut-off valve of the one or more heating target systems when the operation is stopped. To operate the hot water heating system. A circulation circuit having a heat source device and one or a plurality of heat radiation terminals, one or a plurality of forward and return circuits connecting the heat source device and each heat radiation terminal by piping, and an open systern in the circulation circuit; A hot water heating system comprising a circulation pump and one or more forward stop valves and return stop valves in the forward circuit and the return circuit, respectively.
A hot water heating system comprising pressure maintaining means for maintaining the pressure in the pipe at a pressure lower than the pipe withstand pressure value when the operation is stopped. 13. The hot water heating system according to claim 12, wherein the pressure maintaining means includes means for continuously operating the circulation pump for a time until the pressure reaches a pressure lower than the piping withstand pressure value when the operation is stopped. 14. The hot water heating system according to claim 12 or 13, wherein when the operation is stopped, the return side stop valve is closed, the circulation pump is operated for a predetermined time, the circulation pump is stopped, and the forward side stop valve is operated. A method of operating a hot water heating system, wherein the valve is closed. The hot water heating system according to claim 1 or 2, wherein the pressure rise prevention means includes a check valve disposed in the return side circuit. 16. The hot water heating system according to claim 1, wherein one or a plurality of the heat radiating terminals are installed at a higher position than the open systern. The hot water heating system according to any one of claims 1 to 16, wherein the branch pipe portion is piped by a resin pipe. The pressure rise prevention means includes a return-side stop valve provided on the upstream side of the return-side header, an overpressure relief valve having an overpressure drain provided on the upstream side, the overpressure drain and the return header. The hot water heating system according to any one of claims 1, 2, 4 to 8, characterized in that it includes an escape pipe connecting the two.

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