JPH10281395A - Trap device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trap device whereby opening/closing operation of a valve unit can be stably performed. SOLUTION: In a valve chamber 30, a valve unit 41 having an inward space 43 communicating with a discharge port is stored, in an inlet side of the valve chamber 30, a valve seat surface 31 into contact with a contact part 42 of the valve unit 41 is formed, in the downstream thereof, between the valve unit 41 and an inner surface of the valve chamber 30, an inflow space 45 is formed. In a peripheral wall 44 in the downstream of the contact part 42 in the valve unit 41, an introducing hole 46 is formed, which guides a fluid from the inflow space 45 to the inward space 43 of the valve unit 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trap device, such as a steam trap, which opens and closes according to the pressure of a fluid.

[0002]

2. Description of the Related Art Conventionally, as this type of trap device, there are the following first and second modes. In the first embodiment, as shown in FIG. 6, a valve seat member 50 having a valve chamber 51 inside a body 1 and a tapered valve seat surface 52 formed on an inlet side thereof, and a valve chamber 51. And a valve body 60 having a contact portion 61 that is housed and seats on the valve seat surface 52. Further, on the upstream side of the valve seat surface 52 of the valve seat member 50, a valve chamber 51 is provided.
A passage 53 that opens the inside of the body 1 is provided, and a plurality of openings 54 that constantly open the valve chamber 51 to the discharge port 1b are formed in the peripheral wall on the downstream side of the valve seat surface 52.

The valve body 60 is pushed downward by the fluid pressure in the passage 53, and the contact portion 61 is separated from the valve seat surface 51 to open the valve. As a result of this valve opening, the fluid in the body 1 flows through the passage 53 of the valve seat member 50, between the valve seat surface 52 and the contact portion 61, between the outer peripheral surface of the valve body 60 and the valve chamber 51, as shown by the arrow A. The fluid is discharged to the outlet 1b through an annular gap S formed between the inner peripheral surface and the fluid, and a part of the fluid is discharged to the outlet 1b through the opening 54.

In the second embodiment, as shown in FIG. 7, the valve seat surface 52 has a square shape, and the entire valve body 60 has a hemispherical shape. When the valve element 60 is pushed downward to open the valve, the fluid in the body 1 is discharged from the gap S between the valve element 60 and the valve chamber 51 through the lower part of the valve chamber 51 as shown by an arrow A. Discharge to 1b.

[0005]

However, in each of the above embodiments, the gap S around the valve body 60 is large, so that when the fluid flows unevenly in the circumferential direction of the valve body 60, the diameter of the valve body 60 increases. The centering function of the valve element 60 is reduced. For this reason, especially when the valve is closed, the valve body 60 abuts locally on the valve seat surface, so that it is difficult to completely close the valve,
The opening and closing operation of the valve body 60 becomes unstable.

It is an object of the present invention to stably open and close a valve body.

[0007]

According to a first aspect of the present invention, there is provided a trap device, wherein a cylindrical valve body having an inner space communicating with a discharge port is housed in a valve chamber. At the inlet, a valve seat surface is formed to be in contact with the upper contact portion of the valve body, and an inflow space is formed between the valve body and the inner surface of the valve chamber downstream of the valve seat surface, In the peripheral wall on the downstream side of the abutting portion, an introduction hole for guiding fluid from the inflow space to the inner space of the valve body is formed.

According to this configuration, when the valve body is pushed by the pressure of the fluid and the contact portion is separated from the valve seat surface of the valve seat member, the fluid on the inlet side of the valve chamber is in contact with the contact portion. After passing between the valve seat surfaces, it flows into an inflow space formed on the downstream side of the valve seat surface. Then, the gas is introduced from the inflow space into the inner space of the valve body through the introduction hole, and is discharged from the inner space to the outlet. By discharging the fluid in such a path, the amount of the fluid discharged from the gap between the outer peripheral surface of the downstream end portion of the valve body and the inner peripheral surface of the valve chamber is suppressed. The radial swing of the valve element due to the unbalance of the valve element is suppressed, and the opening and closing operation of the valve element is stabilized.

In the embodiment of the present invention, the lower portion of the peripheral wall of the valve body is bulged radially outward from other portions of the peripheral wall,
The clearance between the inner surface of the valve chamber and the inner surface of the valve chamber is set to be smaller than the gap between the intermediate portion forming the inflow space in the peripheral wall and the inner surface of the valve chamber. According to this configuration, at the time of fluid outflow from the inflow space,
Since a small gap between the lower part of the peripheral wall of the valve body and the inner surface of the valve chamber exerts a throttle effect, the outflow of fluid from this gap to the outside is further suppressed. The part is discharged to the discharge port through the introduction hole and the inner space of the valve body. Therefore, the radial movement of the valve body is more effectively suppressed, and the opening and closing operation of the valve body is further stabilized.

According to a third aspect of the present invention, there is provided a skirt which forms a columnar intermediate portion downstream of the contact portion of the valve body and bulges radially outward toward the downstream downstream of the intermediate portion. The outlet of the valve chamber is formed with a curved outflow adjustment surface such that the gap between the inner surface and the skirt portion becomes smaller as the valve body moves in the valve closing direction.

According to this configuration, when the valve is closed, the gap between the inner surface of the valve chamber and the skirt portion of the valve body is reduced. As a result, the velocity of the fluid flowing through the gap increases, so that even if the axis of the valve body is slightly deviated from the axis of the valve chamber, the dynamic pressure of the fluid flowing through the gap changes greatly, Acts in the direction of undo. Since the valve body is centered in this manner, the operation when the valve body is closed is stabilized. In addition, when the valve is opened, the gap increases with the movement of the valve element in the valve opening direction, so that the fluid can be smoothly discharged from the gap. At this time, a tertiary pressure that is smaller than the upstream primary pressure and larger than the downstream secondary pressure is generated inside the valve chamber. Since the skirt portion is pushed in the valve opening direction by the tertiary pressure, valve opening of the valve body is promoted.

It is preferable that a cutout portion is provided in the skirt portion of the valve body so as to widen the gap at a part in the circumferential direction.
Thus, it is possible to prevent the pressure of the fluid acting on the intermediate portion on the upstream side of the skirt portion from excessively increasing and hindering the valve closing operation.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows, as a trap device, for example, a temperature control trap attached downstream of a steam pipe. This temperature control trap includes a body 1 having an inlet 1a and an outlet 1b on both left and right sides, and a cover 2 detachably screwed to an upper opening of the body 1.
Inside the body 1, there is provided a valve seat member 3 screwed to the bottom thereof, and a valve rod 4 having the valve seat member 3 vertically inserted through the valve seat member 3 and provided with a substantially cylindrical valve body 41 at the lower end side. Have been placed.

The valve seat member 3 has a valve chamber 30 for accommodating a valve element 41 at an inner lower portion thereof. An upper inlet side of the valve chamber 30 has a lower portion having a large diameter and an upper portion having a small diameter. The valve seat surface 31 is formed of a tapered surface. The valve chamber 30
Has an inner peripheral surface formed of a cylindrical surface, and a lower end outlet is open. Above the valve seat surface 31, there is provided a passage 32 composed of a vertical hole and a horizontal hole whose upstream end is always open in the body 1.

As is apparent from FIG. 2, the valve body 41 has a tapered contact portion 42 formed on the upper portion (upstream portion) of the valve body 41 so as to be in contact with the valve seat surface 31 and to be seated therein. Exit 1b
(FIG. 1) is provided with an inner space 43 which is always in communication. Also,
When the contact portion 42 separates from the valve seat surface 31 between the outer peripheral surface of the peripheral wall 44 of the valve body 41 and the inner surface of the valve chamber 30, the passage 3
2, a fluid flowing into the inflow space 45 is formed in the upper part of the peripheral wall 44, on the downstream side of the contact portion 42, and in the vicinity thereof, at the upper part of the peripheral wall 44. An introduction hole 46 to be introduced into 43 is formed.

Preferably, four of the introduction holes 46 are formed at equal intervals in the circumferential direction. With this configuration, the fluid in the inflow space 45 can be guided to the inner space 43 of the valve body 41 through the respective introduction holes 46 in a well-balanced manner, so that the valve body 41 in the valve-open state is more stable.

The peripheral wall 44 of the valve body 41 is used as shown in FIG.
In the form, it is formed on the upper side (upstream side), and the valve chamber 30
The first cylindrical hole having a smaller diameter than the diameter of
The wall portion 44a, and downward (downstream) from the first wall portion 44a
Bulges radially outward, and the lower end is the diameter of the valve chamber 30.
The second wall of the tapered cylindrical shape (extended shape) with slightly smaller diameter
Part 44b and a cylindrical third wall part provided on the lower side thereof
44c. And, by the downward movement of the valve body 41,
When the contact portion 42 is separated from the valve seat surface 31 and opened,
A shape is formed between the inner peripheral surface of the valve chamber 30 and the outer peripheral surface of the first wall portion 44a.
The interval T to be formed ₁In contrast, the inner peripheral surface of the valve chamber 30 and the second wall portion
44b formed between the lower end portion (maximum diameter portion) and the outer peripheral surface
Gap T_TwoShould be small enough.

In the embodiment shown in FIG. 1, a sleeve 5 for guiding the valve rod 4 is fixed to the upper side of the valve seat member 3 by press-fitting. Further, two washer-shaped spring receiving members 6 and 6 are inserted into the valve stem 4 above the sleeve 5 so as to receive a compression spring body 8 described below between the members 6 and 6. .

Further, a temperature-sensitive driving member 7 such as a bimetal column formed by superimposing a plurality of bimetals is fitted on the outer periphery of the sleeve 5 between the valve seat member 3 and the lower spring receiving member 6 so as to be vertically movable. It is crowded. The bimetal column 7 is formed by polymerizing a high expansion member 71 such as Cu and a low expansion member 72 such as Ni,
The low expansion member 72 is overlapped as a pair so that the low expansion member 72 is located on the inner side, and the plurality of pairs formed as a pair are fitted into the sleeve 5.

A compression spring body 8 is interposed between the upper and lower spring receiving members 6 and 6 on the outer periphery of the sleeve 5. The compression spring body 8 has two coil springs 81 and 82 having different spring constants and different diameters arranged in parallel, so that the overall height of the compression spring body 8 can be reduced, The height dimension of the temperature control trap can be reduced. When the coil springs 81 and 82 are compressed between the spring receiving members 6 and 6 due to the thermal expansion of the bimetal column 7, the coil springs 81 and 82 come into contact with the coil springs 81 and 82 to contact each other. A cylindrical stopper sleeve 10 for preventing excessive compression of the springs 81 and 82 is provided.

In FIG. 1, an adjusting member 9 capable of controlling the amount of deformation of the bimetal column 7 during the thermal expansion of the bimetal column 7 is provided inside the body 1, and the cover 2 is attached before the temperature control trap is attached to the steam pipe. Adjusting member 9 in open state
Is operated to appropriately set (initial setting) the valve closing temperature due to the thermal expansion of the bimetal column 7, so that the temperature of the drained fluid can be adjusted arbitrarily.

The adjusting member 9 is screwed to a threaded portion 40 provided on the upper side of the valve stem 4 and the spring receiving member 6 on the upper side.
A stopper 91 made of a nut with which the
Lock nut 92 screwed onto the upper side of the stopper 91
It has. Then, while inserting a screwdriver and the like into the operation groove 40a provided at the upper end of the screw portion 40 and screwing it,
Adjust the mounting position of the stopper 91 with respect to the screw portion 40,
That is, by adjusting the upper limit position when the upper spring receiving member 6 is moved upward through the respective coil springs 81 and 82 with the thermal expansion of the bimetal column 7, the valve closing temperature of the valve body 41 can be arbitrarily set. adjust. Thereafter, the lock nut 92 is tightened to prevent the stopper 91 from being displaced.

Next, the operation of the temperature control trap configured as described above will be described. Steam or a mixed fluid of steam and condensate flows into the body 1 from the inlet 1a. When the temperature of the inflowing fluid is equal to or higher than a predetermined temperature, each thermal expansion element (each bimetal group) of the bimetal column 7 thermally expands and deforms vertically (axially) as shown in FIG. Due to the deformation of the bimetal column 7, the coil springs 81 and 82 move upward with the guide member 10 and the spring receiving members 6 and 6, respectively. Then, the upper spring receiving member 6 abuts against the stopper 91 to move the valve rod 4 upward in the valve closing direction, and the abutting portion 42 of the valve body 41 contacts the valve seat surface 31 of the valve seat member 3. The user sits down (the virtual line state in FIG. 2). At this time, the coil springs 81 and 82 are compressed between the upper and lower spring receiving members 6 and 6 by the bimetal column 7 which continues to thermally expand, and the valve body 41 is closed by the coil springs 81 and 82. To prevent the high-temperature steam from being discharged from the discharge port 1b to the outside.

From the above state, when the amount of condensate flowing into the body 1 increases and the fluid in the body 1 drops below a predetermined temperature, the amount of vertical deformation of the bimetal column 7 becomes small, As a result, the coil springs 81 and 82 expand, so that the pressing force of the valve rod 4 in the valve closing direction decreases. The fluid pressure acting on the top surface 4a of the valve rod 4 and the abutting portion 42 of the valve body 41 is applied to the force for moving the valve rod 4 in the valve closing direction by the bimetal column 7 and the coil springs 81 and 82. When the force to move the valve stem 4 in the downward valve opening direction is overcome by the weight or the own weight, the valve stem 4 moves in the valve opening direction, as shown by the solid line in FIG.
The valve body 41 is separated from the valve seat surface 31 and opens.

When the valve body 41 is opened, the fluid mainly composed of condensate in the body 1 flows through the passage 32 of the valve seat member 3,
Between the contact portion 42 of the valve element 41 and the valve seat surface 31, the inflow space 4
5. The air is discharged to the outlet 1b through the respective inlet holes 45 and the inner space 43 of the valve body 31.

At this time, a gap T ₂ between the outer peripheral surface at the lower end of the second wall portion 44 b provided on the peripheral wall 44 of the valve element 41 and the inner peripheral surface of the valve chamber 30 is formed by the outer peripheral surface of the first wall portion 44 a. since setting is made such that the small (T ₂ <T ₁₎ than the interval T ₁ of the between the inner peripheral surface of the valve chamber 30 and the set smaller gap T ₂
Exerts the aperture effect. Therefore, the outflow of fluid from the gap T ₂ is reduced, most of the fluid flowing into the inflow space 45 is discharged to the discharge port 1b through the inner space 43 of the introduction hole 45 and the valve body 41 You. For this reason, a large amount of fluid does not flow out from the outer peripheral surface of the lower end portion of the valve body 41 and the inner peripheral surface of the valve chamber 30 with uneven distribution in the circumferential direction. The radial deflection of the valve body 41 due to the balance is effectively suppressed, and the valve body 41
Opening / closing operation is stabilized.

Here, the relationship of T ₂ <T ₁ is not always necessary. Regardless of the size of the gap T ₂ , the introduction of the introduction hole 45 in the valve body 41 allows the fluid from the gap T ₂ to flow. As a result of suppressing the outflow amount, the radial movement of the valve body 41 is suppressed.

FIG. 3 shows another embodiment of the present invention. The feature is that the axially symmetric valve element 41 has a shape in which there is no introduction hole in the peripheral wall, and a contact portion 42 similar to that of the above-described embodiment is provided on the upper portion (upstream portion). A columnar intermediate portion 47 is formed on the lower side (downstream side), and a flared skirt portion 48 bulging radially outward downward is formed on the lower side. The lower part of the skirt 48 is a column 48a. Further, an outflow adjusting surface 33 formed of an arcuate curved surface is formed on the inner surface of the outlet of the valve chamber 30. This outflow adjustment surface 33 is
As the valve body 41 moves in the valve closing direction (upward), the valve chamber 30
Gap between the skirt portion 48 of the outflow regulating surface 33 and the valve body 41 of the (minimum distance) T ₃ is formed to gradually decrease. When the gap between the inner peripheral surface of the valve chamber 30 and the outer peripheral surface of the intermediate portion 47 is T ₄ , the gap T ₃ in the closed state is １ ／ to 1/3 of the gap T _4. It is preferable to form it so as to be about 7. The gaps T ₃ and T ₄ are constant along the circumferential direction of the valve element 41.

When the valve element 41 moves upward to close the valve, the gap T ₃ gradually decreases, and accordingly, the speed of the fluid flowing through the gap T ₃ increases. Therefore, it deviates the axial center of the valve element 41 is even slightly relative to the axis of the valve chamber 30, the dynamic pressure of the fluid flowing through the gap T ₃ is largely changed, acts in a direction to restore the valve body 41. For example, in the place where the gap T ₃ becomes smaller, the dynamic pressure acting on the skirt portion 48 is increased by an increase in flow velocity, undo the gap T _3, i.e. the valve element 4
1 is pressed in a direction to return to a position concentric with the valve chamber 30. As a result of the centering of the valve element 41, the opening and closing operation of the valve element 41 is stabilized.

[0030] When the valve body 41 is opened by downward movement, the gap T ₃ becomes large, fluid introduced into the valve chamber 30 through the gap T ₃ is discharged to the discharge port 1b. At this time, the valve chamber 30
When the primary pressure on the upstream side (passage 32 side) is P ₁ and the secondary pressure on the downstream side (discharge port 1b side) of the valve chamber 30 is P ₂ ,
Inside the valve chamber 30, a large cubic pressure P ₃ generated than smaller P ₂ than _{P 1 (P 1> P 3} > P 2). This tertiary pressure P ₃ pushes the skirt portion 48 downward in the valve opening direction,
The opening of the valve body 41 is promoted.

In the embodiment shown in FIG. 4 and FIG.
At the lower end (downstream end) of the cart portion 48, the gap T_ThreeYo
Wide gap T_FiveIs formed.
You. In each of the drawings, the lower peripheral wall of the valve body 41 is radially opposed to each other.
Are cut out in the form of a string at four locations facing the
a, and a total of four gaps are formed by the cutouts 41a.
T _FiveAre formed at equal intervals in the circumferential direction. Other
Is the same as the embodiment of FIG.

[0032] In this way, when the valve body 41 moves in the valve closing direction, condensate re steam by reduction of the internal pressure of the valve chamber 30, the P ₃ As a result attempts to rise excessively when, by releasing some of the pressure on the outlet 1b side through the gap T _5, without the re-vaporization is or inhibit closed, allows the closed smoothly. In particular, as described above, by forming a total of four gaps T ₅ at the same intervals, perform a closed stably more smoothly.

[0033]

As described above, according to the present invention, the opening and closing operation of the valve body can be performed stably.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a temperature control trap according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view showing a main part of FIG.

FIG. 3 is a longitudinal sectional view of a main part showing another embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing another embodiment.

FIG. 5 is a bottom view of the valve element.

FIG. 6 is a longitudinal sectional view showing a conventional example.

FIG. 7 is a longitudinal sectional view showing another conventional example.

[Explanation of symbols]

1b: discharge port, 30: valve chamber, 31: valve seat surface, 33: outflow adjustment surface, 41: valve body, 41a: cutout portion, 42: contact portion,
43 ... inner space, 44 ... peripheral wall, 45 ... inflow space, 46 ...
Introducing hole, 47: middle part, 48: skirt part, T ₁ : interval, T ₂ : gap.

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[Procedure amendment]

[Submission date] September 17, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1, as a trap device, which is a trap device mounted for example on the downstream side of the steam pipe. This trap device has inlets 1a on both left and right sides.
And a cover 1 which is detachably screw-connected to an upper opening of the body 1. Inside the body 1, a valve seat member 3 screwed to the bottom thereof, and the valve seat member 3 is vertically inserted,
The valve stem 4 provided with a substantially cylindrical valve body 41 at the lower end is disposed.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

A compression spring body 8 is interposed between the upper and lower spring receiving members 6 and 6 on the outer periphery of the sleeve 5. The compression spring body 8 has two coil springs 81 and 82 having different spring constants and different diameters arranged in parallel, so that the overall height of the compression spring body 8 can be reduced, The height of the trap device can be reduced. When the coil springs 81 and 82 are compressed between the spring receiving members 6 and 6 due to the thermal expansion of the bimetal column 7, the coil springs 81 and 82 come into contact with the coil springs 81 and 82 to contact each other. A cylindrical stopper sleeve 10 for preventing excessive compression of the springs 81 and 82 is provided.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

In FIG. 1, an adjusting member 9 is provided inside the body 1 for controlling the amount of deformation of the bimetal column 7 during thermal expansion, and the cover 2 is opened before the trap device is attached to the steam pipe. Adjusting member 9
Is operated to appropriately set (initial setting) the valve closing temperature due to the thermal expansion of the bimetal column 7, so that the temperature of the drained fluid can be adjusted arbitrarily.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Next, the operation of the trap device having the above configuration will be described. Steam or a mixed fluid of steam and condensate flows into the body 1 from the inlet 1a. When the temperature of the inflowing fluid is equal to or higher than a predetermined temperature, each thermal expansion element (each bimetal group) of the bimetal column 7 thermally expands and deforms vertically (axially) as shown in FIG. Due to the deformation of the bimetal column 7, the coil springs 81 and 82 move upward with the guide member 10 and the spring receiving members 6 and 6, respectively. Then, the upper spring receiving member 6 abuts against the stopper 91 to move the valve rod 4 upward in the valve closing direction, and the abutting portion 42 of the valve body 41 contacts the valve seat surface 31 of the valve seat member 3. The person sits down and enters the valve-closed state (the virtual line state in FIG. 2) .

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

From the above state, when the amount of condensate flowing into the body 1 increases and the fluid in the body 1 drops below a predetermined temperature, the amount of vertical deformation of the bimetal column 7 becomes small, by the coil spring 81, 82 due to this extended, the pressing force of the valve opening direction against the valve rod 4 is increased. These more valve stem 4 to bimetal column 7
To the force to move the coil in the valve closing direction.
The upper surfaces of the springs 81, 82, the top surface 4a of the valve stem 4, and the valve body 41
When the force for moving the valve stem 4 in the downward valve opening direction is overcome by the fluid pressure acting on the contact portion 42 or the own weight, the valve stem 4 moves in the valve opening direction, and FIG. As shown by the solid line, the valve element 41 is separated from the valve seat surface 31 and opens.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG. 1 is a longitudinal sectional view of a trap device according to an embodiment of the present invention.

Claims (4)

[Claims] 1. A trap device that opens a valve under pressure of a fluid, wherein a cylindrical valve body having an inner space communicating with a discharge port is housed in a valve chamber, and an inlet of the valve chamber includes: A valve seat surface that is in contact with an upper contact portion of the valve body is formed, and an inflow space is formed between the valve body and an inner surface of the valve chamber downstream of the valve seat surface, and the contact in the valve body is performed. A trapping device, wherein an introduction hole for guiding a fluid from the inflow space to an inner space of the valve body is formed in a peripheral wall on a downstream side of the portion. 2. The device according to claim 1, wherein a lower portion of the peripheral wall of the valve body bulges radially outward from other portions of the peripheral wall,
A trap device in which a gap between the inner surface of the valve chamber and the inner surface of the valve chamber is set to be smaller than a gap between an intermediate portion forming an inflow space in the peripheral wall and the inner surface of the valve chamber. 3. A trap device for opening a valve by receiving a pressure of a fluid, wherein a valve body is housed in a valve chamber, and a valve seat that is in contact with an upper contact portion of the valve body at an inlet of the valve chamber. A surface is formed, a columnar intermediate portion is formed downstream of the contact portion in the valve body, and a skirt portion bulging radially outward toward the downstream is formed downstream of the intermediate portion. A trap device in which a curved outflow adjustment surface is formed at an outlet of a valve chamber such that a gap between the valve body and the skirt portion decreases as the valve body moves in a valve closing direction. 4. The trap device according to claim 3, wherein the skirt portion of the valve body is provided with a cutout portion that widens the gap in a part in a circumferential direction.