Opening / closing valve mechanism

Abstract

An opening / closing valve mechanism VM according to the present invention comprises: a lever 2 that is coupled to a power source PS and rotates around a fulcrum P1; a valve body 6 that is interlocked with the lever 2 and seated on a valve seat 4; a valve holder 8 that holds the valve body 6; and a rotary shaft body 10 that is coupled to the lever 2 and rotatably supports the valve body 6 and the valve holder 8.

Description

Opening and closing valve mechanism

[0001] The present invention relates to an on-off valve mechanism that opens and closes a valve provided on a lever by power acting on the lever.

[0002] There is a so-called downward-facing bucket steam trap that utilizes the difference in specific gravity between steam and condensate to operate a valve using the buoyancy of a bucket, which is an open float (see, for example, Patent Document 1). In the valve mechanism of a steam trap such as that in Patent Document 1, the bucket and the opening / closing valve mechanism are connected by a lever, and the buoyancy of the bucket acts as a force in the valve closing direction to open and close the valve.

[0003] JP 2010-065831 A

[0004] An example of such a valve mechanism is shown in Figures 5A and 5B. Figure 5A shows the closed valve state, and Figure 5B shows the fully open valve state. As shown in Figure 5A, a valve holder 102 is fixed to a lever 100, and a valve disc 104 is held within the valve holder 102. When the lever 100 rotates due to the floating or sinking of a bucket, the valve disc 104 rotates relative to the valve seat 106 and seats on the valve seat 106. In other words, the valve disc 104 moves in an arc together with the valve holder 102, centered on the lever fulcrum 108.

[0005] 5B , if the valve disc 104 is seated in an inclined state relative to the valve seat 106 by the rotational movement of the lever 100, the valve disc 104 may not be able to seat smoothly on the valve seat 106, which may result in seating failure (failure to close the valve). To seat the valve disc 104 smoothly on the valve seat 106, the valve disc 104 needs to be kept perpendicular to the valve seat 106. By keeping the valve disc 104 perpendicular, it is possible to apply an even valve-closing force to the valve disc 104.

[0006] An object of the present invention is to provide an opening and closing valve mechanism that can achieve a smooth valve closing operation.

[0007] In order to achieve the above object, the opening and closing valve mechanism of the present invention comprises a lever connected to a power source and rotating around a fulcrum, a valve body that seats on a valve seat in conjunction with the lever, a valve holder that holds the valve body, and a rotating shaft that is connected to the lever and supports the valve body and the valve holder so that they can rotate freely.

[0008] With this configuration, the valve and valve holder are rotatably supported on the lever via the rotating shaft, allowing the valve and valve holder to always be oriented vertically relative to the movement of the lever. This reduces the misalignment between the central axis of the valve disc and the central axis of the valve seat. As a result, near the seating (valve closing) position, the force that draws fluid into the valve orifice acts evenly around the valve disc, achieving a smooth seating (valve closing) operation.

[0009] In the on-off valve mechanism of the present invention, the center of gravity of the valve body and the valve holder may be located below the axis of the rotating shaft. With this configuration, the valve body and the valve holder can always be oriented vertically.

[0010] In the on-off valve mechanism of the present invention, when the radial clearance between the valve disc and the rotating shaft is A, the vertical clearance between the valve disc and the valve holder is B, and the horizontal clearance between the valve disc and the valve holder is C, the clearances may be set so that A > B and A > C. According to this configuration, by providing clearances such that A > B and A > C, the valve disc can be maintained in a free state. This makes it possible to prevent forces other than the valve-closing load due to internal pressure from acting on the valve disc, thereby improving the durability of the valve disc.

[0011] The steam trap of the present invention includes the on-off valve mechanism of the present invention and a valve seat member that forms the valve seat. With this configuration, a smooth seating (valve closing) operation can be achieved.

[0012] In the steam trap of the present invention, the power source may be a downward-facing bucket that rises due to the buoyancy of steam and rotates the lever. With this configuration, the opening and closing valve mechanism of the present invention can be applied to a downward-facing bucket steam trap.

[0013] In this case, a weight may be further provided, fixed to the lever on the opposite side of the valve opening mechanism across the bucket connection portion. With this configuration, the valve opening load is determined by the weight of the weight in addition to the weight of the bucket and the lever. This allows for the steam trap to be made more compact and allows for greater design flexibility. Furthermore, the placement of the weight makes it easier to change the valve opening load, facilitating design changes to accommodate different operating pressures.

[0014] The on-off valve mechanism and steam trap of the present invention can achieve smooth valve closing operation.

[0015] Fig. 1 is a cross-sectional view showing a closed state of an on-off valve mechanism according to a first embodiment of the present invention; Fig. 2 is a cross-sectional view showing a maximum open state of the on-off valve mechanism; Fig. 3 is a cross-sectional view showing a valve body and a valve holder of the on-off valve mechanism; Fig. 4 is a vertical cross-sectional view showing a steam trap equipped with the on-off valve mechanism; Fig. 5 is a plan view showing an on-off valve mechanism of a steam trap; Fig. 6 is a cross-sectional view showing a closed state of a conventional on-off valve mechanism; Fig. 7 is a cross-sectional view showing the maximum open state of the on-off valve mechanism;

[0016] Preferred embodiments of the present invention will now be described with reference to the drawings. Fig. 1A is a cross-sectional view showing an on-off valve mechanism VM according to a first embodiment of the present invention in a closed state, and Fig. 1B is a cross-sectional view showing the same in an open state. In the following description, the terms "primary side" and "secondary side" refer to the "primary side" and "secondary side" in terms of the direction of fluid flow relative to the valve port.

[0017] The on-off valve mechanism VM of this embodiment is mounted on a valve device such as a steam trap, and includes a lever 2 connected to a power source PS and swinging about a fulcrum P1, a valve element 6 that opens and closes in conjunction with the lever 2 and seats on a valve seat 4, and a valve holder 8 that holds the valve element 6.

[0018] In this embodiment, lever 2 is made of a plate having a longitudinal direction (the left-right direction in FIG. 1A ), and has a fulcrum P1 at one end of the longitudinal direction (the right end in FIG. 1A ). In other words, lever 2 is supported by, for example, the case of the valve device so as to be rotatable around fulcrum P1.

[0019] A power source PS is connected to the longitudinal middle of the lever 2. The power source PS moves the lever 2 up and down. In other words, when the power source PS is driven, the lever 2 rotates up and down around a fulcrum P1. The power source PS is, for example, a float that operates based on the liquid level, a bucket that operates based on the difference in specific gravity of the fluid, an electric or hydraulic actuator, etc.

[0020] In this embodiment, the valve disc 6 and valve holder 8 are supported near the fulcrum P1 between the connecting portion of the power source PS on the lever 2 and the fulcrum P1. Therefore, when the lever 2 rotates up and down about the fulcrum P1 by driving the power source PS, the valve disc 6 and valve holder 8 also move up and down. In other words, in this embodiment, the up and down direction coincides with the opening and closing direction of the valve disc 6. Specifically, the valve disc 6 and valve holder 8 move in an arcuate orbit around the fulcrum P1.

[0021] The valve element 6 of this embodiment is a tapered needle valve whose diameter gradually decreases toward the tip 6a (upper conical portion in FIG. 1A ). However, the valve element 6 is not limited to a needle valve. The valve is in a closed state when the tip conical portion 6a of the valve element 6 is seated on the valve seat 4 ( FIG. 1A ), and in an open state when the tip conical portion 6a is separated from the valve seat 4 ( FIG. 1B ).

[0022] In this embodiment, the upward direction is the valve closing direction, and the downward direction is the valve opening direction. That is, the valve element 6 moves downward from the closed state of Fig. 1A to open, and reaches the maximum open state of Fig. 1B. The valve element 6 moves upward from the maximum open state of Fig. 1B to close, and reaches the closed state of Fig. 1A. However, the valve opening direction and the valve closing direction are not limited to this, and the upward direction may be the valve opening direction and the downward direction may be the valve closing direction.

[0023] As shown in Figure 2, the valve element 6 of this embodiment has a cylindrical shape with an axis in the valve opening / closing direction, and includes a large diameter portion 6b supported by the lever 2 (Figure 1), a medium diameter portion 6c that protrudes from the large diameter portion 6b in the valve closing direction and has a smaller diameter than the large diameter portion 6b, and a small diameter portion 6d that protrudes from the medium diameter portion 6c in the valve closing direction and has a smaller diameter than the medium diameter portion 6c. The conical tip portion 6a of the small diameter portion 6d gradually decreases in diameter toward the valve closing direction (upward). The conical tip portion may also be provided on the medium diameter portion 6c. The large diameter portion 6b constitutes a supported portion that is supported by the lever 2 (Figure 1), and a valve through hole 6e facing horizontally is formed in the large diameter portion 6b.

[0024] The valve holder 8 has a cylindrical shape, and the valve element 6 is held in its hollow portion. The valve element 6 is held in a free state, i.e., movably, by the valve holder 8. In this embodiment, the valve holder 8 is cylindrical with its axis in the valve opening / closing direction, and the end on the valve closing direction side is closed by a bottom wall 8a, and the end on the valve opening direction side is open.

[0025] The large diameter portion 6b of the valve element 6 is housed in the hollow portion of the valve holder 8. The radial dimension of the internal space of the valve holder 8 is slightly larger than the outer diameter of the large diameter portion 6b of the valve element 6, and the length in the valve opening / closing direction (axial dimension) is slightly larger than the length in the valve opening / closing direction (axial dimension) of the large diameter portion 6b of the valve element 6. A holder through-hole 8c facing horizontally is formed in the peripheral wall 8b of the valve holder 8.

[0026] Two holder through holes 8c are provided radially opposite to each other in the peripheral wall 8b of the valve holder 8. The two holder through holes 8c are provided circumferentially offset by 180°, and the axes of the two holder through holes 8c are aligned.

[0027] When the valve element 6 is housed in the valve holder 8, the axis of each holder through-hole 8c of the valve holder 8 is arranged to substantially coincide with the axis of the valve through-hole 6e of the valve element 6. The diameter of the valve through-hole 6e of the valve element 6 is set to be larger than the diameter of each holder through-hole 8c of the valve holder 8.

[0028] An insertion hole 8d facing in the valve opening / closing direction is formed in the bottom wall 8a of the valve holder 8. The diameter of the insertion hole 8d is set smaller than the outer diameter of the large diameter portion 6b of the valve element 6 and larger than the outer diameter of the medium diameter portion 6c. A part of the medium diameter portion 6c and the small diameter portion 6d of the valve element 6 protrude from the valve holder 8 in the valve closing direction through this insertion hole 8d. The outer peripheral surface of the medium diameter portion 6c of the valve element 6 faces the inner peripheral surface of the insertion hole 8d via a gap. In this way, the valve element 6 is housed in the hollow portion of the valve holder 8 with a predetermined clearance between them. The clearance between the valve element 6 and the valve holder 8 will be described in detail below.

[0029] 1A, the on-off valve mechanism VM of this embodiment includes a rotating shaft 10 that is connected to the lever 2 and rotatably supports the valve element 6 and the valve holder 8. The rotating shaft 10 is, for example, a cylindrical rod-shaped shaft. The central axis 10a of the rotating shaft 10 extends in a direction perpendicular to both the longitudinal direction of the lever 2 and the opening / closing direction (vertical direction) of the valve element 6.

[0030] 2, the rotating shaft 10 passes through the holder through-hole 8c of the valve holder 8 and the valve through-hole 6e of the valve element 6. As a result, the valve element 6 and the valve holder 8 are rotatably supported on the lever 2 via the rotating shaft 10. The center of gravity G of the valve element 6 and the valve holder 8 is located below the axis 10a of the rotating shaft 10.

[0031] The radial clearance between the valve element 6 and the rotary shaft 10 is A, the vertical clearance between the valve element 6 and the valve holder 8 is B, and the horizontal clearance between the valve element 6 and the valve holder 8 is C. In this case, the relationships A>B and A>C are set.

[0032] Here, each of the clearances A, B, and C is set in a reference state in which the axis of the valve through hole 6e of the valve element 6, the axis of the holder through hole 8c of the valve holder 8, and the axis 10a of the rotating shaft body 10 are aligned. That is, in the reference state, the difference between the radius of the valve through hole 6e of the valve element 6 and the radius of the rotating shaft body 10 is clearance A. In the reference state, the distance between the end face on the closing direction side of the large diameter portion 6b of the valve element 6 and the inner surface of the bottom wall 8a of the valve holder 8 is clearance B. In the reference state, the distance between the outer peripheral surface of the medium diameter portion 6c of the valve element 6 and the inner peripheral surface of the insertion hole 8d of the valve holder 8 is clearance C.

[0033] In addition, in the standard state, the distance between the outer peripheral surface of the large diameter portion 6b of the valve body 6 and the inner peripheral surface of the peripheral wall 8b of the valve holder 8 is defined as clearance D. In this embodiment, clearance C is set to be larger than clearance D (C>D). Therefore, clearance A is necessarily larger than clearance D (A>D).

[0034] 2, the center of gravity G of the valve body 6 and the valve holder 8 is located below the axis 10a of the rotary shaft 10. This allows the valve body 6 and the valve holder 8 to always be oriented vertically.

[0035] In the on-off valve mechanism VM configured as described above, the valve element 6 and the valve holder 8 are rotatably supported on the lever 2 shown in Fig. 1B via the rotating shaft 10. This allows the valve element 6 and the valve holder 8 to always face vertically in response to the movement of the lever 2. In other words, even if the lever 2 is tilted relative to the horizontal direction as shown in Fig. 1B, the valve element 6 and the valve holder 8 will rotate on the rotating shaft 10 due to their own weight and face vertically.

[0036] This reduces the positional deviation between the center C1 of the valve disc 6 and the center C2 of the valve seat 4. As a result, near the valve closed position shown in Figure 1A, the force that sucks the fluid into the valve port 4a acts evenly around the circumferential direction of the valve disc 6, achieving a smooth seating (valve closing) operation.

[0037] 1A is fixed to the lever 2, the load applied to the valve disc 6 when the valve is closed increases depending on the lever ratio, which may result in increased wear on the valve disc 6. In the above configuration, the valve disc 6 is housed in the valve holder 8 in a free state, and the clearance is set so that the valve closing load due to internal pressure is minimized when the valve is closed.

[0038] 2, the clearance A between the valve disc 6 and the rotating shaft 10, the vertical clearance B between the valve disc 6 and the valve holder 8, and the horizontal clearance C between the valve disc 6 and the valve holder 8 are set so that A > B and A > C. By providing such clearances, the valve disc 6 can be maintained in a free state. This prevents forces other than the valve-closing load due to internal pressure from acting on the valve disc 6, improving the durability of the valve disc 6.

[0039] Figure 3 is a cross-sectional view showing the steam trap 20 equipped with the on-off valve mechanism VM of this embodiment, and Figure 4 is a plan view of the on-off valve mechanism VM mounted on the steam trap 20. In the following description, common reference symbols are used for components that are the same as those in Figures 1A, 1B, and 2, and detailed description thereof will be omitted.

[0040] The steam trap 20 in Fig. 3 is a downward-facing bucket-type steam trap that utilizes the difference in specific gravity between steam and condensate (drainage) D to operate an on-off valve mechanism VM using the buoyancy of a bucket 22, which is an open float, to discharge the condensate (drainage) D. That is, in the example of Fig. 3, the bucket 22 constitutes the power source for the on-off valve mechanism VM. The bucket 22 has a cylindrical shape with a bottom that is open at the bottom and closed at the top. A vent hole 22a is formed in the upper wall of the bucket 22.

[0041] The steam trap 20 has a case 26 that forms a bucket chamber 24 that houses the bucket 22, and a lever 2 to which the bucket 22 is connected at an intermediate portion 28 in the longitudinal direction (the left-right direction in FIG. 3 ). In other words, the intermediate portion 28 of the lever 2 forms a connecting portion 28 to which the bucket 22 is connected in the lever 2. As shown in FIG. 4 , the bucket 22 is connected to the intermediate portion 28 of the lever 2 via a bucket rotation shaft 25.

[0042] As shown in Fig. 3, the lever 2 is connected to a case 26 at one end in the longitudinal direction (the left end in Fig. 3) and rotates around a fulcrum P1. In this embodiment, the lever 2 is supported by the case 26 via a bracket 29 attached to the case 26. More specifically, as shown in Fig. 4, the lever 2 is connected to the bracket 29 via a lever rotation shaft 27 so as to be rotatable around the fulcrum P1. A valve element 6 of the on-off valve mechanism VM is attached to the lever 2 between a connecting portion 28 and the fulcrum P1, near the fulcrum P1.

[0043] At the beginning of ventilation, initial condensate (drain) D flows into the bucket chamber 24 shown in Figure 3, and the downward bucket 22, due to its lack of buoyancy, is lowered to an open valve position. When steam flows into the downward bucket 22, the bucket 22 rises due to buoyancy, and the lever 2 rotates upward around the fulcrum P1. This causes the valve element 6 of the on-off valve mechanism VM to rise and close the valve. When the inflow of steam into the downward bucket 22 stops, the steam in the bucket 22 decreases due to cooling and condensation, etc., and the bucket 22 loses buoyancy, lowers, and the lever 2 rotates downward around the fulcrum P1. This causes the valve element 6 of the on-off valve mechanism VM to lower and open the valve.

[0044] The case 26 has a case body 30 that is open at the top and a cover body 32 that is connected to the case body 30 by fastening members 34 such as bolts. The area surrounded by the case body 30 and the cover body 32 forms the bucket chamber 24. Condensate (drain) D and steam are trapped inside the bucket chamber 24. An inlet 36 is formed at the top of the case body 32, through which drain D containing steam S is introduced into the bucket chamber 24. The inlet 36 and the bucket chamber 24 are connected by an inlet passage 35. The inlet passage 35 communicates with the bucket chamber 24 from below.

[0045] The cover body 32 is a member shaped to close the upper opening of the case body 30, and a discharge path 38 for discharging condensate (drainage) D is formed inside the cover body 32. In detail, a primary portion 38a of the discharge path 38 is formed inside the cover body 32, and a secondary portion 38b of the discharge path 38 is formed in the case body 30. An outlet 40 for discharging condensate (drainage) D from the bucket chamber 24 is formed in the upper part of the case body 32.

[0046] A communication passage 42 that connects the bucket chamber 24 and the discharge passage 38 is provided near the upper end of the discharge passage 38 in the cover body 32. The communication passage 42 is formed by a valve seat member 44 that is interposed between the on-off valve mechanism VM and the cover body 32.

[0047] The valve seat member 44 is a cylindrical member having an axis C2 extending in the vertical direction in Figure 3, with its lower side opening to the bucket chamber 24 and its upper side opening to the discharge passage 38. The valve seat member 44 is connected to the cover body 32 by, for example, screwing.

[0048] The valve element 6 of the on-off valve mechanism VM is disposed below the valve seat member 44 in the bucket chamber 24. The valve seat 4 on which the valve element 6 sits is formed at the lower end of the valve seat member 44. The valve seat 4 is formed so as to narrow the communicating passage 42 radially inward, i.e., toward the axial center C2 of the valve seat member 44 (communicating passage 42). A hole formed by the valve seat 4 in the valve seat member 44 constitutes a valve port 46.

[0049] A valve port 46 of the valve seat member 44 communicates between the bucket chamber 24 and the communication passage 42. In other words, when the valve element 6 is seated on the valve seat 4, the valve port 46 is closed and the condensate (drain) D does not flow (closed valve state). When the valve element 6 moves away from the valve seat 4, the valve port 46 is opened and the condensate (drain) D flows (open valve state).

[0050] The steam trap 20 in Fig. 3 is provided with a weight 50 that assists the operation of the on-off valve mechanism VM. The weight 50 is fixed to the lever 2 on the side opposite the on-off valve mechanism VM (the right side in Fig. 3 ) across the connecting portion 28 of the bucket 22. In the example in Fig. 3 , the weight 50 applies a downward force to the lever 2, assisting the opening operation of the on-off valve mechanism VM.

[0051] The weight 50 is preferably made of a corrosion-resistant material, such as austenitic stainless steel such as SUS304. However, the material of the weight 50 is not limited to this. The weight of the weight 50 varies greatly depending on the operating pressure, for example, the valve structure, size, etc., and is set appropriately taking these factors into consideration. In the example of FIG. 3, the weight 50 has a rectangular parallelepiped shape. However, the structure and shape of the weight 50 are not limited to this.

[0052] Next, the operation of the bucket-type steam trap 20 of this embodiment will be described. At the beginning of ventilation, condensate (drainage) D flows into the bucket chamber 24 from below through the inlet 36 and the inlet passage 35. When only condensate (drainage) D is present, the bucket 22 has no buoyancy, the valve element 6 is in an open state, and the condensate (drainage) D passes through the communication passage 42 and the discharge path 38 and is discharged to the outside from the outlet 40. After the condensate (drainage) D is discharged, steam S flows into the bucket 22 and raises the bucket 22 by buoyancy. In other words, the steam S is trapped within the bucket 22. This causes the lever 2 to rotate upward about the fulcrum P1, and the valve element 6 of the on-off valve mechanism VM rises to close the valve.

[0053] At this time, the valve disc 6 and valve holder 8 rotate around the rotary shaft 10 due to their own weight, so they always face vertically (up and down). This prevents the valve disc 6 from seating on the valve seat 4 in an inclined state, achieving a smooth valve closing operation. Furthermore, because the valve disc 6 faces vertically, the positional deviation between the center C1 of the valve disc 6 and the center C2 of the valve seat 4 is reduced. As a result, the force sucking the condensate (drainage) D acts evenly around the circumferential direction of the valve disc 6, ensuring that the valve disc 6 seats reliably on the valve seat 4 and closes the valve.

[0054] When the valve is closed and the inflow of steam S into the downward bucket 22 is stopped, the steam S in the bucket 22 decreases due to cooling and condensation, leakage from the vent hole 22a, etc., and the bucket 22 loses buoyancy and descends. This causes the lever 2 to rotate downward about the fulcrum P1, and the valve element 6 of the opening / closing valve mechanism VM descends to open the valve.

[0055] At this time, a downward force, i.e., a force in the valve opening direction, acts on the lever 2 due to the weight of the weight 50 in addition to the weights of the bucket 22 and the lever 2. Therefore, the valve opening operation of the valve body 10 becomes smooth.

[0056] When the valve is opened, the valve element 6 and valve holder 8 rotate around the rotary shaft 10 due to their own weight. As a result, the valve element 6 and valve holder 8 always face vertically (up and down) (the state shown in FIG. 1B). When the valve is opened, condensate (drain) D and steam S flow into the bucket chamber 24, and the same operation is repeated.

[0057] The steam trap 20 configured as described above provides the same effects as the on-off valve mechanism VM shown in Figures 1A, 1B, and 2. That is, because the valve disc 6 is oriented vertically, a smooth seating (valve closing) operation is achieved, and the force of sucking the condensate (drain) D acts evenly around the circumferential direction of the valve disc 6, ensuring that the valve disc 6 is reliably seated on the valve seat 4 (valve closing).

[0058] If the bucket 22 is fixed to the longitudinal end of the lever 2 at a position eccentric from the central axis, the bucket 22 may tilt when the on-off valve mechanism VM operates. If the bucket 22 tilts, there is a concern that the bucket 22 may come into contact with the case 26, hindering the up-and-down movement of the bucket 22.

[0059] If the bucket 22 is connected to the lever 2 on the central axis as in the above configuration, the bucket 22 will not tilt during operation, but it is difficult to ensure the lever ratio required to open the valve. Therefore, in the above configuration, a weight 50 is fixed to the lever 2 on the side opposite the on-off valve mechanism VM, across the connecting portion 28 of the bucket 22. With this configuration, a valve opening load is obtained by the weight of the weight 50 in addition to the force from the bucket 22. This allows a sufficient valve opening load to be obtained even if the distance between the fulcrum P1 of the lever 2 and the connecting position of the bucket 22 is short. As a result, the steam trap 20 can be made smaller and the design flexibility can be increased. Furthermore, the placement of the weight 50 makes it easier to change the valve opening load, facilitating design changes to accommodate operating pressures.

[0060] 3 and 4, an example in which the on-off valve mechanism VM of the present invention is applied to a downward bucket type steam trap 20 has been described, but the on-off valve mechanism VM of the present invention can also be applied to a lever float type steam trap. In this case, the on-off valve mechanism VM opens in the upward direction and closes in the downward direction.

[0061] The present invention is not limited to the above-described embodiment, and various additions, modifications, and deletions are possible without departing from the spirit of the present invention. For example, although the weight 50 is provided in the steam trap of the above-described embodiment, the weight 50 may be omitted. Therefore, such an arrangement is also included within the scope of the present invention.

[0062] DESCRIPTION OF SYMBOLS 2 Lever 4 Valve seat 6 Valve disc 8 Valve holder 10 Rotating shaft 10a Axis center of rotating shaft 20 Steam trap 22 Bucket (power source) 28 Bucket connection part at lever 44 Valve seat member 50 Weight A Radial clearance between valve disc and rotating shaft B Vertical clearance between valve disc and valve holder C Horizontal clearance between valve disc and valve holder G Center of gravity between valve disc and valve holder P1 Fulcrum PS Power source VM Opening / closing valve mechanism

Claims

1. An opening and closing valve mechanism comprising: a lever connected to a power source and rotating around a fulcrum; a valve disc that seats on a valve seat in conjunction with the lever; a valve holder that holds the valve disc; and a rotating shaft connected to the lever and rotatably supporting the valve disc and the valve holder.

2. An opening / closing valve mechanism as claimed in claim 1, wherein the center of gravity of the valve body and the valve holder is located below the axis of the rotating shaft body.

3. An opening / closing valve mechanism as claimed in claim 1 or 2, wherein when the radial clearance between the valve element and the rotating shaft is A, the vertical clearance between the valve element and the valve holder is B, and the horizontal clearance between the valve element and the valve holder is C, the opening / closing valve mechanism is set so that A > B and A > C.

4. A steam trap comprising: an on-off valve mechanism according to any one of claims 1 to 3; and a valve seat member that forms the valve seat.

5. A steam trap according to claim 4, wherein the power source is a downward-facing bucket that rises due to the buoyancy of steam and rotates the lever.

6. The steam trap according to claim 5, further comprising a weight fixed to the lever on the side opposite the opening / closing valve mechanism, with the bucket connection portion of the lever sandwiched therebetween.

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