JP7530109B2 - Valve mechanism of lever float steam trap - Google Patents

Description

The present invention relates to the valve mechanism of a lever float steam trap, which has a float at one end of a lever and a valve body at the other end, and opens and closes the valve body using the buoyancy of the float.

In a lever float steam trap, the float and valve mechanism are connected by a lever, and the buoyancy of the float acts as a force in the valve opening direction to open and close the valve (for example, Patent Document 1). In a valve mechanism like that of Patent Document 1, when condensate accumulates in the case above a certain water level and the buoyancy of the float required to open the valve is generated, the condensate is discharged.

JP 2021-124138 A

In a lever float steam trap, condensate (liquefied steam) is discharged to the outside regardless of the drain temperature. Therefore, it is desirable to quickly discharge drain that is below the saturation temperature at the steam pressure used. In particular, since low-temperature drain remains in the piping immediately after ventilation begins, if the pressure is suddenly increased, water hammer may occur. For this reason, it is necessary to gradually increase the pressure from a low pressure to discharge the initial drain and warm up the piping. As a result, it takes time to start up the system.

The present invention aims to provide a valve mechanism for a lever float steam trap that can shorten the start-up time of the equipment.

In order to achieve the above object, the valve mechanism of the lever float steam trap of the present invention comprises a lever connected to a float and swinging around a fulcrum, a valve seat member forming a valve seat on which a valve disc sits, a valve holder that holds the valve disc and is movable vertically, a valve stem that connects the valve holder and the lever and moves the valve holder vertically by swinging the lever to open and close the valve disc, and a temperature-sensitive expansion mechanism provided on the valve stem. The temperature-sensitive expansion mechanism acts in the direction of opening the valve disc at low temperatures and in the direction of closing the valve disc at high temperatures. The temperature-sensitive expansion mechanism has, for example, a bimetal as a temperature sensor.

In a lever float steam trap, there is no need to close the valve if drainage below the saturation temperature is present. With this configuration, a temperature-sensitive expansion mechanism is incorporated in the valve stem of the valve mechanism, so the valve body remains open regardless of the internal water level at low temperatures. This allows drainage to be discharged without using the buoyancy of the float. In particular, drainage can be discharged immediately after ventilation begins, regardless of the internal water level, shortening the time required to start up the system.

Furthermore, with a lever float steam trap, when the system is shut off, the steam is stopped and the temperature drops. This causes the steam to condense and become drain, which accumulates inside. With conventional lever float steam traps, this drain is not discharged unless the water level reaches a certain level. If the drain that has accumulated inside is left for a long period of time, it can cause the case to rust. For this reason, conventionally, the drain was drained through a drain hole in the case. However, this increases the amount of drain draining work, and forgetting to do this can cause the case to rust.

With the above configuration, the valve body remains open regardless of the internal water level at low temperatures, so that the drainage accumulated inside can be discharged even when the system is stopped. This not only eliminates the need for drainage drainage, but also prevents the case from rusting.

In the present invention, the valve holder may be connected to the valve stem so that its height can be adjusted. With this configuration, the temperature at which the valve body opens can be adjusted by adjusting the height of the valve holder.

In this case, the temperature-sensitive expansion mechanism may have multiple bimetals attached to the valve stem. With this configuration, in addition to adjusting the height of the valve holder, the temperature at which the valve opens can be adjusted by changing the number of bimetals.

The valve mechanism of the lever float steam trap of the present invention allows drainage immediately after ventilation begins, regardless of the internal water level, shortening the time required to start up the system.

1 is a vertical cross-sectional view showing a lever float steam trap equipped with a valve mechanism according to a first embodiment of the present invention. FIG. FIG. 2 is a cross-sectional view showing a main part of the lever float steam trap. FIG. 4 is an enlarged vertical cross-sectional view of the valve mechanism at a low temperature. FIG. 4 is an enlarged vertical cross-sectional view of the valve mechanism at a high temperature.

A preferred embodiment of the present invention will now be described with reference to the drawings. In the following description, "upstream" and "downstream" refer to the "upstream" and "downstream" of the fluid flow direction.

Figure 1 is a schematic diagram showing a lever float steam trap equipped with a valve mechanism VM according to a first embodiment of the present invention. A lever float steam trap uses the buoyancy of a float 1 to open and close a drain valve 2 to drain condensate (drain) D. The lever float steam trap has a case 6 that forms a float chamber 4 that houses the float 1, and a lever 8 whose front end (one end) is connected to the float 1.

The lever 8 is connected to the float 1 at its front end 8a and swings around the fulcrum P1. That is, the lever 8 is supported by the case 6 so as to be able to swing freely around the fulcrum P1 by a known structure. The valve body 10 of the drain valve 2 is attached to the lever 8 between the front end 8a and the fulcrum P1, near the fulcrum P1. The weight 9 that assists in the opening operation of the valve body 10 of the drain valve 2 is attached to the lever 8. The weight 9 is provided behind the fulcrum P1 of the lever 8. The weight of the weight 9 varies greatly depending on the operating pressure, for example the valve structure and size, and is set appropriately taking these factors into consideration.

When the liquid level of drain D in the float chamber 4 rises, the float 1 rises and the lever 8 swings around the fulcrum P1 in the direction of the arrow A1. This causes the valve body 10 of the drain valve 2 to rise and open, and the drain D is discharged. When the liquid level of drain D in the float chamber 4 falls, the float 1 falls and the lever 8 swings around the fulcrum P1 in the direction of the arrow A2. This causes the valve body 10 of the drain valve 2 to fall and close. The details of the drain valve 2 will be described later.

The case 6 that constitutes the exterior body has a flange portion 14 of the case body 12 that is open at one end (the left end in the figure), and a cover body 16 is connected to it by a fastening member 18 such as a bolt. The area surrounded by the case body 12 and the cover body 16 forms the float chamber 4. Steam is trapped in the float chamber 4. An inlet 100 is formed at the top of the case body 12 to introduce the primary side fluid containing steam and drain D into the float chamber 4.

The cover body 16 is a member shaped to close the opening at one end (left end) of the case 6. Inside the cover body 16, an outflow passage 20 with a circular cross section is formed for discharging the drain D. The outflow passage downstream portion 20a is connected to the upper side of the outflow passage 20. The outflow passage downstream portion 20a is connected to an outlet (not shown) to the outside. Furthermore, a communication passage 22 is provided near the lower end of the outflow passage 20 in the cover body 16. The communication passage 22 connects the float chamber 4 and the outflow passage 20.

The communication passage 22 is formed by a spacer 24 interposed between the drain valve 2 and the cover body 16. The spacer 24 is a cylindrical member extending in the left-right direction of FIG. 1, with one end in the longitudinal direction opening to the float chamber 4 and the other end opening to the outflow passage 20. A first flange 26 is formed at one end in the longitudinal direction of the spacer 24 (the float chamber 4 side), and a second flange 28 is formed in the longitudinal middle part. A plurality of bolt insertion holes 28a are formed in the second flange 28. The spacer 24 is connected to the cover body 16 by bolts 30 inserted into the bolt insertion holes 28a.

The drain valve 2 is disposed upstream (toward the float chamber 4) of the spacer 24 in the float chamber 4. The drain valve 2 discharges the drain D that flows into and accumulates in the float chamber 4. The drain valve 2 is bolted to the first flange 26 of the spacer 24.

As shown in FIG. 3, the drain valve 2 has the valve body 10 and a valve seat member 34. The valve seat member 34 forms the valve seat 32 on which the valve body 10 sits. The valve seat member 34 has a valve hole 36 formed therein, and the upper end (upstream end) of the valve hole 36 communicates with the valve seat 32. In other words, when the valve body 10 sits on the valve seat 32, the valve hole 36 is closed and drain D does not flow (closed state). When the valve body 10 moves away from the valve seat 32, the valve hole 36 is opened and drain D flows (open state).

The lower end (downstream end) of the valve hole 36 is connected to the outflow passage 20 via the communication passage 22 in FIG. 1. The drain valve 2 is equipped with a valve case 38. The valve case 38 supports the valve body 10 so that it can move freely in the vertical direction, and supports the valve seat member 34 so that it cannot move relative to the valve body 10.

The upstream passage 40 is formed in the upper part of the interior of the valve case 38, and the downstream passage 42 is formed in the lower part of the interior. The upstream passage 40 is connected to the float chamber 4, and the downstream passage 42 is connected to the communication passage 22. Inside the valve case 38 in FIG. 2, a valve seat member mounting hole 44 is formed that connects the upstream passage 40 and the downstream passage 42. In detail, the valve seat member 34 is attached to the valve seat member mounting hole 44, and the upstream passage 40 and the downstream passage 42 are connected by the valve hole 36 of the valve seat member 34.

A valve body insertion hole 46 is formed in the upper part of the valve case 38. The valve body insertion hole 46 vertically connects the float chamber 4 and the upstream passage 40. In this embodiment, the valve body insertion hole 46 is formed by a bushing 45 attached to the valve case 38. The valve body 10 passes through the hollow hole (valve body insertion hole) 46 of this cylindrical bushing 45.

The valve case 38 in FIG. 1 has a screw insertion hole (not shown) and is connected to the first flange 26 of the spacer 24 with a bolt 25. A gasket 48 is interposed between the spacer 24 and the valve case 38. In this way, the valve case 38 having the valve seat 32 is attached to the cover body 6 via the spacer 24.

Next, the valve body 10 will be described. As shown in FIG. 3, the drain valve 2 further includes a valve holder 50 and a valve shaft portion 52. The valve holder 50 holds the valve body 10 and is movable up and down within the valve body insertion hole 46. The valve shaft portion 52 connects the valve holder 50 to the lever 8, and the swinging of the lever 8 moves the valve holder 50 up and down to open and close the valve body 10. In other words, the valve body 10 is connected to the lever 8 via the valve shaft portion 52 and the valve holder 50.

The valve shaft portion 52 has an upper end connected to the lever 8 by a first connecting pin 54, and a lower end connected to the valve body 10. The valve shaft portion 52 has a connecting member 55 connected to the lever 8 and a valve shaft member 56 connected to the valve body 10, and the connecting member 55 and the valve shaft member 56 are connected. In detail, the connecting member 55 has an upper end connected to the lever 8, and the valve holder 50 is fixed to the lower part. A male thread 55a shown in FIG. 3 is formed on the peripheral surface of the lower part of the connecting member 55. In addition, a shaft insertion hole 55b extending in the vertical direction is formed on the lower surface of the connecting member 55.

The valve shaft member 56 has an upper end connected to the connecting member 55 and a lower end connected to the valve body 10. In detail, the upper end of the valve shaft member 56 is inserted into the shaft insertion hole 55b of the connecting member 55, and the lower end is connected to the valve body 10 via a flange-shaped flange member 65. In other words, the valve shaft member 56 is movable in the vertical direction relative to the connecting member 55. The outer diameter of the flange member 65 is larger than the outer diameter of the valve body 10.

The valve holder 50 is connected to the connecting member 55 of the valve shaft portion 52 so that the height can be adjusted freely. In detail, a screw hole 50a that opens upward is formed in the upper part of the valve holder 50, and the male screw 55a of the connecting member 55 is screwed into this screw hole 50a from above. The male screw 55a of the connecting member 55 is formed to be sufficiently longer than the screw hole 50a of the valve holder 50. This allows the height of the valve holder 50 to be freely adjusted. Meanwhile, the valve holder 50 moves up and down within the valve body insertion hole 46.

A valve body insertion hole 58 extending in the vertical direction is formed in the lower part of the valve holder 50. In this embodiment, the valve body insertion hole 58 is a stepped through hole. In other words, the valve body insertion hole 58 has an upper large diameter hole 62 and a lower small diameter hole 64, sandwiched between a step portion 60. An annular receiving portion 66 that protrudes radially inward is formed at the lower end of the small diameter hole 64. In other words, the receiving portion 66 is formed with a smaller diameter than the small diameter hole 64.

The valve body 10 has a vertically long cylindrical shape, and its lower end 10a is tapered downward. The lower end 10a seats on the valve seat 32, closing the valve hole 36. The upper end of the valve body 10 is connected to the flange member 65.

The outer diameter of the valve body 10 is smaller than the inner diameter of the receiving portion 66. The outer diameter of the flange member 65 is larger than the diameter of the small diameter hole 64 and smaller than the diameter of the large diameter hole 62. Therefore, when the valve body 10 descends, the lower surface of the flange member 65 abuts against the step 60. In other words, the flange member 65 constitutes a stopper 65 that regulates the lower limit position of the valve body 10 relative to the valve holder 50. A compression spring 68 is inserted between the receiving portion 66 and the stopper (flange portion) 65.

The valve mechanism VM of the lever float steam trap is composed of the lever 8 to which the float 1 is connected, the valve seat member 34 that forms the valve seat 32, the valve holder 50 that holds the valve body 10, the valve stem portion 52 that connects the lever 8 and the valve holder 50, and the compression spring 68.

The valve mechanism VM further includes a temperature-sensitive expansion mechanism 70. The expansion mechanism 70 is provided on the valve stem 52, and acts to open the valve body 10 at low temperatures (the state shown in FIG. 3), and acts to close the valve body 10 at high temperatures (the state shown in FIG. 4). The valve closing temperature at which the valve body 10 closes is, for example, 90°C. However, the valve closing temperature is not limited to this.

The temperature-sensitive expansion mechanism is, for example, a bimetal 69 that is a temperature sensor. In this embodiment, the temperature-sensitive expansion mechanism 70 has multiple bimetals 69 attached to the valve stem portion 52. In detail, multiple annular bimetals 69 are attached to the valve stem member 56 of the valve stem portion 52.

One end face (upper face in FIG. 3) of the bimetal 69 abuts against the lower face of the connecting member 55 of the valve stem 52, and the other end face (lower face in FIG. 3) abuts against the upper face of the stopper portion (flange portion) 65. In detail, multiple bimetals 69 are stacked vertically, with the upper face of the uppermost bimetal 69 abutting against the lower face of the connecting member 55 of the valve stem 52, and the lower face of the lowermost bimetal 69 abutting against the upper face of the stopper portion (flange portion) 65.

The valve shaft member 56 of the valve shaft portion 52 is connected to the connecting member 55 so as to be freely movable in the vertical direction. Therefore, when the bimetal 69 contracts at low temperatures as shown in FIG. 3, the valve body 10 moves upward. When the bimetal 69 expands and deforms into a bowl shape at high temperatures as shown in FIG. 4, the valve body 10 moves downward.

Next, the operation of the lever float steam trap of this embodiment will be described. When the system is started up, if the inside of the float chamber 4 is at or above the valve closing temperature, the valve body 10 is closed as shown in FIG. 4, and if it is below the valve closing temperature, the valve body 10 is open as shown in FIG. 3. A primary fluid containing high-temperature steam flows into the float chamber 4 in FIG. 1, and drain D mixed with this primary fluid accumulates in the float chamber 4. If this drain D is below the set water level, the float 1 is held in the lower limit position shown by the two-dot chain line in FIG. 1. At this time, the drain valve 2 is in a closed state with the valve hole 36 in FIG. 3 blocked by the valve body 10, and the high-temperature steam contained in the primary fluid is trapped in the float chamber 4.

When the drain D accumulated in the float chamber 4 exceeds the set water level, as shown by the solid line in Figure 1, the lever 8 receives buoyancy from the drain D and rotates around the fulcrum P1 in the direction of the arrow A1, and the valve body 10 (Figure 3), which moves upward integrally with the float 1, opens the valve hole 36. This opens the drain valve 2, and the fluid containing the drain D passes through the valve hole 36, the downstream passage 42 inside the valve case 38, the communication passage 22 inside the spacer 24 in Figure 1, and the outflow passage 20, and is discharged from the downstream part of the outflow passage 20a to the outside of the steam trap.

When the drain D in the float chamber 4 decreases due to discharge, the float 1 descends under its own weight, and the lever 8 rotates around the fulcrum P1 in the direction of the arrow A2 to enter the fully closed state.

When the system stops, the flow of steam (primary fluid) into the float chamber 4 stops, and the temperature inside the float chamber 4 drops. As a result, the steam condenses into drain, which accumulates inside the float chamber 4. When the drain water level inside the float chamber 4 is below a certain level and the temperature of the float chamber 4 is high, the bimetal 69 expands as shown in Figure 4, and the drain valve 2 is closed.

When the temperature in the float chamber 4 drops further and the drain water level in the float chamber 4 is below a certain level and the temperature inside the float chamber 4 becomes low, the bimetal 69 contracts as shown in Figure 3 and the drain valve 2 opens. This allows the drain in the float chamber 4 to be discharged.

According to the above configuration, the expansion and contraction mechanism 70 allows the valve body 10 to maintain an open state regardless of the internal water level at low temperatures. Therefore, drainage can be discharged without using the buoyancy of the float 1. In particular, since drainage can be discharged immediately after ventilation begins, regardless of the internal water level, the time required to start up the system can be shortened.

In addition, because the valve body 10 remains open regardless of the internal water level at low temperatures, the drain D that has accumulated inside can be discharged even when the system is stopped. This not only eliminates the need to remove the drain, but also prevents the case 6 from rusting.

The valve holder 50 is connected to the connecting member 55 of the valve shaft 52 so that its height can be adjusted freely. This allows the temperature at which the valve body 10 opens to be adjusted by adjusting the height of the valve holder 50.

The extension mechanism 70 has multiple bimetals 69 attached to the valve shaft member 56. This allows the temperature at which the valve body 10 opens to be adjusted by changing the number of bimetals 69 in addition to adjusting the height of the valve holder 50.

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. Therefore, such additions, modifications, and deletions are also included within the scope of the present invention.

REFERENCE SIGNS LIST 1 float 8 lever 10 valve body 32 valve seat 34 valve seat member 50 valve holder 52 valve stem 69 bimetal 70 temperature-sensitive expansion mechanism VM valve mechanism

Claims (2)

A lever connected to the float and swinging about a fulcrum;
a valve seat member forming a valve seat on which the valve element is seated;
a valve holder that holds the valve body and is movable vertically;
a valve shaft portion that connects the valve holder and the lever and moves the valve holder in a vertical direction by swinging the lever, thereby opening and closing the valve body;
A temperature-sensitive expansion mechanism provided in the valve stem;
Equipped with
The temperature-sensitive expansion mechanism acts in a direction in which the valve body opens at low temperatures and acts in a direction in which the valve body closes at high temperatures ,
A valve mechanism of a lever float steam trap , wherein the valve holder is connected to the valve stem portion so as to be freely adjustable in height . 2. The valve mechanism of a lever float steam trap according to claim 1 , wherein the temperature-sensitive expansion mechanism has a plurality of bimetals attached to the valve stem portion.

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