Flow Control Valve

Abstract

A flow rate control valve that can suppress the wasteful discharge of fluid. A flow rate regulating valve 4 of the present invention regulates the flow rate of a second fluid S according to the temperature of a first fluid W. The flow rate regulating valve 4 includes a first fluid line 28 through which the first fluid W flows, a second fluid line 30 through which the second fluid S flows, a drive source 32 that expands and contracts according to the temperature of the first fluid W flowing through the first fluid line 28, and a valve element 34 that is driven by the drive source 32 to open and close the second fluid line 30. With respect to the opening and closing direction of the valve element 34, an outlet 4d of the second fluid line 30 is located on the opposite side of the drive source 32 from an inlet 4c of the second fluid line 30.

Description

[Technical Field]

[0001] The present invention relates to a flow rate regulating valve that regulates the flow rate of one fluid depending on the temperature of the other fluid. [Background technology]

[0002] A hot water supply system is known that heats room-temperature feedwater using a heating fluid such as steam as a heat source and adjusts the feedwater temperature regardless of the feedwater flow rate to maintain a constant temperature (see, for example, Patent Document 1). Such a hot water supply system has the advantage that it requires no electricity and can be installed as long as steam and feedwater are available. The main components of a hot water supply system include a heat exchanger that heats the feedwater with steam, a steam regulating valve that adjusts the steam flow rate according to the hot water temperature at the heat exchanger outlet, and a hot and cold water mixing valve that changes the mixing ratio of high-temperature hot water and room-temperature water to match the set temperature. The steam regulating valve in Patent Document 1 is a type of flow control valve that adjusts the flow rate of one fluid, steam, depending on the temperature of the other fluid, water, and uses a thermoelement as its driving source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5463096 Summary of the Invention [Problem to be solved by the invention]

[0004] In a hot water supply system like that described in Patent Document 1, after hot water supply is stopped, the steam regulating valve closes and the steam supply stops. The temperature of the water around the temperature-sensing part of the thermoelement drops over time due to heat radiation. This temperature drop causes the steam regulating valve to open again and steam to flow. This causes the temperature of the temperature-sensing part of the thermoelement to rise again and the steam regulating valve to close again. In this way, when hot water supply is stopped, the steam regulating valve repeatedly opens and closes.

[0005] An example of a conventional steam regulating valve is shown in Figure 3. The steam regulating valve 100 in Figure 3 has, as passages for steam S, a main passage 101 through which the steam S flows, shown by a solid line, and an auxiliary passage 102 through which the steam S flows, shown by a dashed line. The auxiliary passage 102 extends to the vicinity of the temperature-sensing part 103a of the thermoelement 103, and is set to quickly raise the temperature of the thermowax 103 and quickly close the steam regulating valve 100.

[0006] However, as shown in Figure 3, when the steam regulating valve 100 is slightly open and the steam flow rate is low, steam S does not easily flow into the auxiliary passage 102. In other words, steam S does not easily flow near the temperature-sensing part 103a of the thermo-element 103. As a result, it takes time for the temperature-sensing part 103a of the thermo-wax 103 to rise in temperature, and it takes time for the valve to close. As a result, unnecessary steam S is discharged from the main passage 101 of the steam regulating valve 100.

[0007] An object of the present invention is to provide a flow rate control valve that can suppress the wasteful discharge of fluid. [Means for solving the problem]

[0008] To achieve the above object, a flow control valve of the present invention is a flow control valve that adjusts the flow rate of a second fluid depending on the temperature of a first fluid, and includes: a first fluid line through which the first fluid flows; a second fluid line through which the second fluid flows; a drive source that expands and contracts depending on the temperature of the first fluid flowing through the first fluid line; and a valve element that is driven by the drive source to open and close the second fluid line. With respect to the opening and closing direction of the valve element, an outlet of the second fluid line is located on the opposite side of the drive source from an inlet of the second fluid line. The first fluid is, for example, water, and the second fluid is, for example, steam.

[0009] With this configuration, steam flows near the driving source even when the valve disc is slightly open. This allows the driving source to be heated quickly even when the flow rate of the second fluid is very low. As a result, the time required for the valve to close is shortened, and unnecessary discharge of the second fluid is reduced.

[0010] The hot water supply system of the present invention adjusts the temperature of water supplied by heating room temperature water using the second fluid as a heat source, and includes a heat exchanger that heats the water with the second fluid, and a flow control valve of the present invention that adjusts the flow rate of the second fluid supplied to the heat exchanger in accordance with the temperature of the water discharged from the heat exchanger. Here, "room temperature water" refers to water at a temperature of 15 to 35°C.

[0011] This configuration shortens the time required to close the valve and reduces the unnecessary discharge of the second fluid. This also reduces the thermal load on other components such as the heat exchanger and flow control valve. Furthermore, since the system only requires replacing the flow control valve, it can be easily applied to existing hot water supply systems. [Effects of the Invention]

[0012] According to the flow rate adjustment valve and hot water supply system of the present invention, the time required to close the valve is shortened, and unnecessary discharge of the second fluid can be suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram showing a hot water supply system including a steam regulating valve, which is a type of flow rate regulating valve, according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the steam regulating valve. [Figure 3] FIG. 1 is a cross-sectional view showing a steam regulating valve of a conventional hot water supply system. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will now be described with reference to the drawings. Fig. 1 shows a schematic configuration diagram of a hot water supply system SY equipped with a steam regulating valve 4, which is a type of flow rate regulating valve, according to a first embodiment of the present invention.

[0015] The flow rate control valve 4 is a flow rate control valve that adjusts the flow rate of the second fluid S depending on the temperature of the first fluid W. The flow rate control valve 4 of this embodiment is a steam control valve 4 that adjusts the flow rate of the steam S depending on the temperature of the water W. That is, in this embodiment, the first fluid W is water W, and the second fluid S is steam S. However, the first fluid and the second fluid are not limited to this.

[0016] The hot water supply system SY of this embodiment heats room temperature water W using steam S, which is a second fluid, as a heat source, and adjusts and keeps the supply water temperature constant regardless of the supply water flow rate. The hot water supply system SY of this embodiment has the advantage that it does not require electricity and can be installed with just steam S and water W. Here, "room temperature water" refers to water at 15 to 35°C. In the following description, "upstream" and "downstream" refer to "upstream" and "downstream" in the flow direction of the steam S or water W.

[0017] The hot water supply system SY includes, as its main components, a heat exchanger 2, a steam regulating valve 4, and a hot and cold water mixing valve 6. The heat exchanger 2 heats room-temperature water W with steam S to generate hot water W. In the following description, "hot water W" refers to the water W heated by the heating fluid S in the heat exchanger 2. The steam regulating valve 4 adjusts the flow rate of the steam S in accordance with the temperature of the hot water W discharged from the heat exchanger 2. In other words, in this embodiment, the steam regulating valve 4 constitutes a regulating valve that adjusts the flow rate of the heating fluid supplied to the heat exchanger 2 in accordance with the temperature of the water W discharged from the heat exchanger 2. The hot and cold water mixing valve 6 changes the mixing ratio of the hot water W and room-temperature water W in accordance with the set temperature.

[0018] The heat exchanger 2 is, for example, a "plate heater" in which a plurality of plates are stacked and passages for steam S and passages for water W are alternately arranged between the plates. However, the heat exchanger 2 is not limited to a plate heater.

[0019] A water supply passage 8 is connected to the water inlet 2a of the heat exchanger 2, a hot water passage 11 is connected to the water outlet 2b of the heat exchanger 2, a steam supply passage 12 is connected to the steam inlet 2c of the heat exchanger 2, and a steam discharge passage 14 is connected to the steam outlet 2d of the heat exchanger 2. Water W from the water inlet 2a and steam S from the steam inlet 2c exchange heat in the heat exchanger 2, and the hot water W after the heat exchange is discharged from the water outlet 2b, and the steam S after the heat exchange is discharged from the steam outlet 2d.

[0020] Water W at room temperature, for example, tap water W, flows through the water supply passage 8. A first check valve 10 is provided in the water supply passage 8. The first check valve 10 prevents the water W from flowing back from the heat exchanger 2 into the water supply passage 8.

[0021] Hot water W that has undergone heat exchange in the heat exchanger 2 flows through the hot water passage 11. The above-mentioned steam regulating valve 4 and hot and cold water mixing valve 6 are provided in the hot water passage 11. In detail, the hot water W that is discharged from the water outlet 2b of the heat exchanger 2 flows into the steam regulating valve 4 from the water supply inlet 4a of the steam regulating valve 4 and flows out from the water supply outlet 4b of the steam regulating valve 4. The opening degree of the steam regulating valve 4 is adjusted depending on the temperature of the hot water W that flows into the steam regulating valve 4. The hot water W that flows out from the water supply outlet 4b is introduced into the hot and cold water mixing valve 6.

[0022] A mixed water passage 16 branches off from the water supply passage 8 upstream of the first check valve 10. In other words, the mixed water passage 16 branches off from a branch point 17 of the water supply passage 8. The mixed water passage 16 is connected to the hot and cold water mixer 6. In the hot and cold water mixer 6, hot water W from the hot water passage 11 is mixed with room-temperature water W from the mixed water passage 16 to generate hot water W at a desired temperature, which is supplied via the hot water passage 13. Here, "hot water W" refers to the hot water W and room-temperature water W mixed by the hot and cold water mixer 6. A second check valve 18 is provided in the mixed water passage 16. The second check valve 18 prevents water W from flowing back from the hot and cold water mixer 6 into the mixed water passage 16.

[0023] Steam S, which is a heating fluid, flows through the steam supply passage 12. A steam regulating valve 4 is provided in the steam supply passage 12. In detail, the steam S flows into the steam regulating valve 4 from a steam inlet 4c of the steam regulating valve 4 and flows out from a steam outlet 4d of the steam regulating valve 4. As described above, the flow rate of the steam S that flows into the steam regulating valve 4 is regulated by the temperature of the hot water W that flows in from the feedwater inlet 4a. The steam S that flows out from the steam outlet 4d is introduced into the heat exchanger 2. Details of the steam regulating valve 4 will be described later.

[0024] Steam S discharged from a steam outlet 2d of the heat exchanger 2 flows through the steam discharge passage 14. A steam trap 20 is provided in the steam discharge passage 14. The steam trap 20 discharges drain D and traps the steam S.

[0025] The steam regulating valve 4 will be described using Figure 2. In the following description, the steam inlet 4c side in Figure 2 will be referred to as the upper side, and the steam outlet 2d side as the lower side. As shown in Figure 2, the steam regulating valve 4 has a cylindrical casing 22 with open upper and lower ends, an upper cover 24 that closes the upper opening, and a lower cover 26 that closes the lower opening. The upper cover 24 and the lower cover 26 are detachably attached to the casing 22 with a plurality of bolts. The casing 22, the upper cover 24, and the lower cover 26 are made of stainless steel, for example. However, the materials of the casing 22, the upper cover 24, and the lower cover 26 are not limited to this.

[0026] The steam regulating valve 4 includes a water supply line 28 through which water W flows, a steam line 30 through which steam S flows, a drive source 32 that expands and contracts depending on the temperature of the water W flowing through the water supply line 28, and a valve element 34 that is driven by the drive source 32 to open and close the steam line 30. In this embodiment, the water supply line 28 constitutes a first fluid line through which a first fluid flows, and the steam line 30 constitutes a second fluid line through which a second fluid flows.

[0027] Water supply line 28 is formed inside casing 22. Water supply line 28 has a driving source housing 36 in which driving source 32 is disposed, a primary water supply line 28a that runs from water supply inlet 4a to driving source housing 36, and a secondary water supply line 28b that passes through driving source housing 36 and then runs to water supply outlet 4b.

[0028] The driving source 32 has a thermoelement 38 that expands and contracts depending on the water temperature in the water supply line 28. The thermoelement 38 of the driving source 32 is disposed in the driving source housing portion 36 of the water supply line 28. More specifically, the temperature-sensing portion 38a of the thermoelement 38 is disposed in the driving source housing portion 36 of the water supply line 28.

[0029] The steam regulating valve 4 further has a piston 40 that moves up and down due to the expansion and contraction of the thermoelement 38. That is, in this embodiment, the opening and closing direction of the steam regulating valve 4 coincides with the up and down direction. The piston 40 is a shaft member that extends up and down, with a base end (lower end) 40a that abuts against the thermoelement 38 and a tip end (upper end) 40b to which the valve body 34 is attached. In this embodiment, the thermoelement 38 and the piston 40 are housed inside a case 39 and formed into a unit. That is, the piston 40 moves up and down while being guided by the case 39.

[0030] Case 39 has a lower end 39a that is threadedly connected (screwed) to a cylindrical member 45 that is fitted onto the inner peripheral surface of casing 22, and an upper end 39b that is threadedly connected (screwed) to the outer peripheral surface of a cylindrical portion 48 (described below) that is formed on top cover 24. In other words, top cover 24, cylindrical member 45, case 39, valve body 34, piston 40, and drive source 32 are formed as a unit that is detachable from casing 22.

[0031] The valve body 34 has a large-diameter annular portion 34a and a small-diameter valve body portion 34b, and the annular portion 34a and the valve body portion 34b are connected via a reduced-diameter portion 34c. The reduced-diameter portion 34c has an inclined shape that gradually reduces in diameter as it goes upward.

[0032] The tip portion 40b of the piston 40 and the cylindrical spring holder 42 attached thereto are inserted into the hollow hole of the annular portion 34a. The outer diameter of the spring holder 42 is set to be approximately the same as, but slightly smaller than, the inner diameter of the hollow portions of the annular portion 34a and the valve body portion 34b.

[0033] The valve body portion 34b is cylindrical with an open lower end and a closed upper end by a top wall 34ba. The opening at the lower end of the valve body portion 34b is connected to the opening at the upper end of the cylindrical portion 34a. A first spring member 44 is interposed between the top wall 34ba of the valve body portion 34b and the upper surface of the spring holder 42. The first spring member 44 is biased in the opening direction (downward) by, for example, a coil spring. An inner peripheral surface 34bb of the valve body portion 34b functions as a guide for the first spring member 44.

[0034] The steam line 30 is formed inside the casing 22 and inside the top cover 24. A valve body 34 is arranged in the steam line 30. A steam inlet 4c of the steam line 30 is provided in the peripheral wall of the top cover 24, and a steam outlet 4d is provided in the peripheral wall of the casing 22. Details of the positional relationship between the steam inlet 4c and the steam outlet 4d of the steam line 30 will be described later.

[0035] A portion of the steam line 30 is formed inside the top cover 24. The steam line 30 inside the top cover 24 opens downward, and this opening forms the valve port 24a. In other words, the opening 24b at the lower end of the top cover 24 forms the valve seat 24b. When the valve body portion 34b of the valve body 34 rises and abuts against the valve seat 24b of the top cover 24, the steam line 30 closes.

[0036] A downwardly protruding cylindrical portion 48 is formed on the lower surface of the upper lid 24. The inner diameter of the cylindrical portion 48 is set to be approximately the same as, but slightly larger than, the outer diameter of the cylindrical portion 34a of the valve body 34. In other words, the inner peripheral surface of the cylindrical portion 48 functions as a guide for the valve body 34.

[0037] A male thread 48a is formed on the outer peripheral surface of the cylindrical portion 48. The female thread formed on the upper end portion 39b of the case 39 is fastened to the male thread 48a of the cylindrical portion 48, whereby the case 39 is supported by the upper lid 24.

[0038] A second spring member 50 is interposed between the upper cover 24 and the valve body 34. The second spring member 50 is, for example, a coil spring, and is biased in the opening direction (downward). In this embodiment, the second spring member 50 is set to have a smaller "spring force" than the first spring member 44.

[0039] A cylindrical portion 48b that protrudes downward is formed on the lower surface of the cylindrical portion 48. The upper end of the second spring member 50 abuts against the lower surface of the cylindrical portion 48 on the radially inner side of the case 39 and on the radially outer side of the cylindrical portion 48b.

[0040] A step portion 34aa is formed between the annular portion 34a and the reduced diameter portion 34c of the valve body 34. The lower end of the second spring member 50 abuts against the step portion 34aa on the radially inner side of the case 39 and on the radially outer side of the reduced diameter portion 34c. In this embodiment, the inner diameter surface of the case 39 functions as a guide for the second spring member 50.

[0041] When the temperature of the water W in the water supply line 28 is low, the spring force of the second spring member 50 moves the valve element 34 downward, and the valve element 34 is separated from the valve seat 48ba. In other words, the steam line 30 is opened, and steam S is supplied to the heat exchanger 2 (FIG. 1).

[0042] When steam S is supplied to heat exchanger 2, the temperature of water W in water supply line 28 supplied from heat exchanger 2 rises. When the temperature of water W in water supply line 28 rises, thermoelement 38 is activated and an upward force is exerted by piston 40. When this upward force from drive source 32 becomes greater than the spring force of second spring member 50, valve element 34 moves upward and seats on valve seat 24b. In other words, steam line 30 is closed and the supply of steam S to heat exchanger 2 (FIG. 1) is stopped.

[0043] In this embodiment, when the temperature of the thermoelement 38 reaches 90°C, the valve element 34 seats on the valve seat 24b. However, the temperature of the thermoelement 38 may continue to rise even after the valve element seats, and the piston 40 may continue to extend even after seating. The first spring member 44 is designed to absorb this force of the piston 40.

[0044] When the supply of steam S to the heat exchanger 2 is stopped, the temperature of the water W in the water supply line 28 supplied from the heat exchanger 2 drops. When the temperature of the water W in the water supply line 28 drops, the upward force acting on the piston 40 decreases. When the spring force of the second spring member 50 becomes greater than the upward force from the drive source 32, the valve element 34 moves downward and separates from the valve seat 24b. In other words, the steam line 30 is opened, and the supply of steam S to the heat exchanger 2 (FIG. 1) resumes.

[0045] Next, the structure of the steam line 30 will be described. With respect to the opening and closing direction of the valve element 34, the outlet 4d of the steam line 30 (steam outlet 4d) is arranged on the opposite side of the drive source 32 to the inlet 4c of the steam line 30 (steam inlet 4c). In the illustrated example, the inlet 4c of the steam line 30 is arranged at the upper end of the steam regulating valve 4, and the outlet 4d of the steam line 30 is arranged at the lower end of the steam regulating valve 4. Furthermore, with respect to the vertical direction, the drive source 32 is arranged between the outlet 4d and inlet 4c of the steam line 30.

[0046] A portion of the steam line 30 upstream of the valve port 24a is formed inside the upper cover 24. A portion of the steam line 30 downstream of the valve port 24a is formed inside the casing 22 and is closed by the lower cover 26. In other words, the steam line 30 extends from a steam inlet 4c formed in the upper cover 24 downward inside the casing 22 to reach the lower cover 26 and communicates with a steam outlet 4d formed in the peripheral wall of the lower end of the casing 22.

[0047] The steam line 30 is provided radially outside and below the thermo-element 38. More specifically, the steam line 30 is provided radially outside and below the drive source accommodating portion 36 in which the temperature-sensing portion 38a of the thermo-element 38 is disposed. The steam line 30 is separated from the water supply line 28 by a partition wall of the casing 22 on the radial outside of the drive source accommodating portion 36. Furthermore, the steam line 30 is separated from the water supply line 28 by a partition member 52 on the lower side of the drive source accommodating portion 36.

[0048] The partition member 52 is fitted onto the inner circumferential surface of the lower end of the cylindrical member 45. The partition member 52 is made of a metal having a higher thermal conductivity than the casing 22 and the cylindrical member 45. In this embodiment, the partition member 52 is made of a copper alloy. This allows the heat of the steam S flowing through the steam line 30 to be efficiently transferred to the drive source accommodating portion 36 of the water supply line 28 and the temperature-sensing portion 38a of the thermo-element 38 arranged therein. However, the material of the partition member 52 is not limited to a copper alloy.

[0049] According to the above configuration, the inlet 4c of the steam line 30 is located at the upper end of the flow rate adjustment valve 4, the outlet 4d is located at the lower end of the flow rate adjustment valve 4, and the thermowax 38, which is the driving source 32, is located between the inlet 4c and the outlet 4d in the vertical direction. Therefore, even when the valve element 34 is slightly open, the steam S always flows near the thermowax 38. Specifically, the steam S always flows radially outward and below the temperature-sensing portion 38a of the thermo-element 38. This allows the temperature of the temperature-sensing portion 38a of the thermo-element 38 to be quickly raised even when the flow rate of the steam S is very small. As a result, the time required for the valve to close is shortened, and unnecessary discharge of the steam S can be suppressed.

[0050] In this way, by suppressing the unnecessary discharge of steam S, it is possible to reduce the thermal load on other components such as the flow control valve 4, the heat exchanger 2 in Figure 1, and the hot and cold water mixing valve 6. Furthermore, since the flow control valve 4 only needs to be replaced, the flow control valve 4 of the present invention can be easily applied to existing hot water supply systems.

[0051] The present invention is not limited to the above-described embodiments, and various additions, modifications, and deletions are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, steam S is used as the second fluid, but the second fluid is not limited to steam S and may be, for example, hot water at 80 to 95°C. In this case, the drive source of the flow rate adjustment valve 4 is operated by hot water. Therefore, such a configuration is also included in the scope of the present invention. [Explanation of symbols]

[0052] 2 Heat exchanger 4 Steam regulating valve (flow regulating valve) 4c Steam line inlet (steam inlet) 4d Steam line outlet (steam outlet) 28 Water supply line (first fluid line) 30 Steam line (second fluid line) 32 Drive source (thermoelement) 34 Valve body S Steam (second fluid) W Water (first fluid) SY hot water system

Claims

1. A flow control valve that adjusts the flow rate of steam according to the temperature of water, a first fluid line through which the water flows; a second fluid line through which the vapor flows; a drive source that expands and contracts depending on the temperature of the water flowing through the first fluid line; a valve element driven by the drive source to open and close the second fluid line; Equipped with A flow rate adjustment valve in which the outlet of the second fluid line is located on the opposite side of the drive source from the inlet of the second fluid line in terms of the opening and closing direction of the valve body.

2. A hot water supply system that adjusts the supply water temperature by heating water at room temperature using a second fluid as a heat source, a heat exchanger for heating the water with the second fluid; a flow rate adjusting valve that adjusts the flow rate of the second fluid to be supplied to the heat exchanger in accordance with the temperature of the water discharged from the heat exchanger; Equipped with The flow rate adjusting valve is a first fluid line through which the water flows; a second fluid line through which the second fluid flows; a drive source that expands and contracts depending on the temperature of the water flowing through the first fluid line; a valve element driven by the drive source to open and close the second fluid line; and A hot water supply system, wherein the outlet of the second fluid line is arranged on the opposite side of the drive source from the inlet of the second fluid line in terms of the opening and closing direction of the valve body.

3. 3. The hot water system of claim 2, wherein the second fluid is steam.

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