JPH049519Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disk-type steam trap, and particularly to a structure for eliminating irregularities in operating cycles.

[Conventional technology]

Conventionally, as a disc-type steam trap, a sheet member has been used, in which double inner and outer ring seats are partitioned on the same plane by an annular groove, the inner side of the inner ring seat is in communication with an inflow hole, and the annular groove is in communication with an outflow hole. is formed separately,
It is known to incorporate this sheet member into a trap body having a pair of inlet ports and outlet ports. Sealing grooves are formed around the inflow hole and around the outflow hole on the surface of the sheet member placed on the trap body, and a gasket made of tetrafluoroethylene resin is tightly fitted in each sealing groove. This gasket is fitted into the trap body and presses against the mounting surface of the trap body to prevent a short circuit between the inflow hole and the outflow hole or leakage between the outflow hole and the outside.

Gaskets made of polytetrafluoroethylene resin have various advantages such as requiring less tightening force than metal gaskets, and are easy to maintain because they do not seize like asbestos gaskets. , widely used in disc steam traps.

However, the disadvantage of gaskets made of tetrafluoroethylene resin is that their gel point is as low as about 327°C, and their coefficient of linear expansion is 10 to 15 times higher than that of metal gaskets. Therefore, if the steam trap is continuously used, the gasket fitted in the sealing groove will expand in volume due to the rise in temperature, and in particular, the volumetric expansion force of the inner gasket fitted around the inflow hole will cause the sheet member to expand. The center part is distorted as if rising, causing an imbalance in the flatness of the inner ring seat and outer ring seat on which the disk is seated. As a result, the operating time from the end of condensate discharge until the condensate discharge starts again becomes irregular, resulting in a problem that the operating cycle becomes irregular.

In order to solve this problem, as described in Japanese Unexamined Patent Publication No. 56-80590, volume expansion of the gasket is applied to at least a part of the contact surface between the gasket and the sealing groove provided around the inflow hole of the sheet member. It has been proposed that a gap be provided to provide a corresponding relief.
In this case, even if the gasket undergoes volumetric expansion, the expansion is allowed to escape through the gap, thereby preventing the sheet member from being distorted.

[The problem that the idea attempts to solve]

However, as mentioned above, gaskets made of polytetrafluoroethylene resin have a low gel point, so as the gasket expands in volume, it causes flow (plastic deformation) into the gap, reducing the surface pressure of the gasket and reducing sealing performance. There is a drawback that it does. and,
As the temperature rises, the flow becomes more pronounced, so the sealing performance deteriorates, and there is a risk that the inflow hole and the outflow hole will eventually short-circuit (short pass). In other words, in the conventional case, the volumetric expansion can only be released when the gasket flows, but if the gasket flows, the sealing performance deteriorates, which is a trade-off.

Therefore, the purpose of this invention is to prevent the gasket from flowing and eliminate the deterioration in sealing performance.
To provide a disc type steam trap capable of preventing distortion from spreading to an inner ring seat.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an inner circumferential groove whose bottom diameter is approximately the same as the outer diameter of the gasket, on the inner surface of the inflow hole, and at a position closer to the inner ring seat than the gasket mounting part. An elastic portion having a substantially L-shaped cross section that can be elastically deformed toward the inner ring seat as the gasket expands in volume is integrally formed with the sheet member on the inner peripheral side of the gasket.

[Effect]

When the gasket fitted into the sealing groove undergoes volumetric expansion due to an increase in temperature, the elastic portion holding the gasket and having a substantially L-shaped cross section is elastically deformed upward. This absorbs the volumetric expansion of the gasket, eliminates the spread of distortion to the inner ring seats, and prevents the flatness of the inner and outer rings from becoming out of alignment.
Further, since the gasket is surrounded by an elastic portion, the gasket does not flow, and a decrease in surface pressure can be prevented.

When using a steam trap at low steam pressure, the saturation temperature is low and the volumetric expansion of the gasket is small, so irregular operating cycles are not much of a problem, but as the steam pressure increases, the saturation temperature also increases. Therefore, the volumetric expansion of the gasket increases, and the amount of distortion of the inner ring seat also increases. In the case of a disc type steam trap, even if the inner ring seat is distorted by just 5 μm, it will have a significant effect on the operating cycle. Conventionally, when the volume of the gasket expands, it is not possible to prevent the strain from spreading to the inner ring seat, and the strain is prevented only when the gasket causes a flow in the direction of the gap, resulting in a delay in improving the operating cycle. In this case, since the elastic portion bends as the volume expands, irregularities in the operating cycle can be prevented from the beginning.

When common martensitic stainless steel is used as the material for the sheet member, the elastic limit strain is about 5%, so the shape of the elastic part is determined so that it can absorb the volumetric expansion of the gasket within this range. do it. Since an inner circumferential groove with approximately the same diameter as the outer circumferential surface of the gasket is formed on the inner ring seat side of the elastic part, the elastic part can easily bend toward the inner ring seat, even if the gasket's volumetric expansion is large. It can be easily absorbed by the elastic deformation of the elastic part.

〔Example〕

FIG. 1 shows the overall structure of an example of a disk-type steam trap according to the present invention, which is composed of a trap body 1, a sheet member 10, a cap 30, a disk 40, and a cover 50.

A pair of inlet port 2 and outlet port 3 are formed in the trap body 1, and a strainer 4 is disposed inside the inlet port 2. A mounting surface 5 is formed in the upper center of the trap body 1.
A disc-shaped sheet member 10 is placed on this placement surface 5, and the peripheral edge 11 of the sheet member 10 is connected to the lower surface of the peripheral wall 31 of the cap 30 which is screwed into the inner screw 6 of the trap body 1. It is crimped and fixed.

As shown in FIG. 2, the upper surface of the sheet member 10 is provided with double inner and outer ring seats 13 and 14 which are partitioned into the same plane by an annular groove 12, and the inner ring seat 13 has an inlet hole. 15 , and the bottom of the annular groove 12 communicates with an outflow hole 16 . By incorporating the sheet member 10 into the trap body 1, the inflow hole 15 is connected to the inlet port 2 and the outflow hole 16 is connected to the inlet port 2.
communicate with the outlet port 3, respectively. An annular sealing groove 18 is formed around the inflow hole 15 on the lower surface (placing surface) 17 of the sheet member 10 that contacts the placement surface 5 of the trap body 1, and a sealing groove is also formed around the outflow hole 16. A sealing groove 19 concentric with 18 is formed. Then, annular gaskets 20 and 21 having a rectangular cross section made of polytetrafluoroethylene resin or a similar material are tightly fitted into both sealing grooves 18 and 19.
By press-fitting the gaskets 20 and 21 to the mounting surface 5 of the trap body 1, short-circuiting between the inflow hole 15 and the outflow hole 16 and leakage between the outflow hole 16 and the outside are prevented.

An inner circumferential groove 23 is formed on the inner surface of the inflow hole 15 and in the vicinity of the inner ring seat 13 side from the mounting portion of the inner gasket 20.
The groove bottom diameter D of No. 3 is set approximately equal to the outer diameter of the gasket 20. Due to the inner circumferential groove 23, an elastic portion 22 having a substantially L-shaped cross section is formed integrally with the sheet member 10 on the inner circumferential side of the gasket 20.
This elastic portion 22 is elastically deformed in the direction of the inner ring seat 13 as the gasket 20 expands in volume, and the seat member 1
It has a function to prevent distortion from spreading to 0.

The elastic portion 22 bulges on the inner surface of the inflow hole 15, and a portion 7 of the trap body 1 corresponding to the inflow hole 15 continues with this elastic portion 22 and bulges inward. A restriction is formed in the inflow path.

A variable pressure chamber 32 is formed between the sheet member 10 and the cap 30, and a disk 40 is housed within this variable pressure chamber 32 without being restricted at all.

The disk 40 is formed in a flat plate shape so that it can be commonly seated on the inner and outer ring seats 13 and 14, and due to the correspondence between the intermediate pressure generated in the variable pressure chamber 32 and the fluid pressure on the inlet hole 15 side, The disk 40 controls the flow of condensate and intermittently discharges only the condensate from the outlet hole 16.

The cover 50 is screwed onto the external screw 8 of the trap body 1 so as to cover the outside of the cap 30.
By configuring an air jacket outside the cap 30, heat radiation from the variable voltage chamber 32 is suppressed. Incidentally, if a heat insulating material 51 such as glass wool is placed in this jacket portion, heat radiation from the variable voltage chamber 32 can be further suppressed.

Explanation of Operation In the steam trap configured as described above, the gaskets 20 and 21 fitted into the sealing grooves 18 and 19 expand in volume as the operating temperature rises, but the peripheral edge 11 of the sheet member 10
Therefore, the volumetric expansion of the outer gasket 21 has no effect on the sheet member 10. However, the volumetric expansion of the inner gasket 20 provided around the inflow hole 15 distorts the central portion of the sheet member 10 so that it rises upward. However, since an elastic portion 22 having a substantially L-shaped cross section that can be easily elastically deformed is formed on the inner circumferential side of the inner gasket 20, the elastic portion 22 is elastically deformed upward at the same time as the gasket 20 expands in volume, and the inner ring seat 13
prevent distortion from spreading to Therefore, the inner and outer ring seats 1
3 and 14, and irregularities in the operating cycle can be prevented. Furthermore, since the periphery of the gasket 20 is covered with the elastic part 22,
The gasket 20 does not flow, and the elastic stress of the elastic portion 22 causes the gasket 20 to flow.
Since the surface pressure of the inflow hole 15 and the outflow hole 1
There are no problems such as short circuit with 6.

Further, in the above embodiment, a restriction is formed in the inlet hole 15 by the elastic portion 22 and the bulging portion 7, but this restriction has the following effects. In other words, in conventional steam traps that do not have a restriction in the inlet hole, the originally necessary steam is also discharged at the end of condensate discharge, and the passage of this steam causes the disk to close, resulting in a loss of steam. The disadvantage is that it becomes large. On the other hand, if a throttle is provided as in this example, a part of the saturated water existing at the boundary between steam and condensate will cause a pressure drop and quickly vaporize when passing through the throttle, resulting in reevaporation steam. passes under the disk at high speed, causing the disk to close. As a result, the emission of originally necessary steam is suppressed, and steam loss can be reduced.

Note that in the above embodiment, the elastic portion 22 is connected to the inlet hole 15.
Although a case has been shown in which the elastic portion 22 bulges inward to form a diaphragm, the elastic portion 22 does not necessarily need to bulge into the inflow hole 15 .

[Effect of idea]

As is clear from the above explanation, according to the present invention, an inner circumferential groove is formed on the inner surface of the inflow hole, and the groove bottom diameter is approximately the same as the outer diameter of the gasket. Since the deformable elastic part having a substantially L-shaped cross section is formed, when the gasket expands in volume, the elastic part bends and absorbs the thermal expansion. Therefore, it is possible to prevent distortion from spreading to the inner ring seat of the seat member, and it is possible to prevent irregularities in the operating cycle.

In addition, since the gasket is surrounded by an elastic part and does not have a gap unlike conventional gaskets, the gasket does not flow, and the surface pressure of the gasket does not decrease due to the elastic stress of the elastic part. This can eliminate problems caused by short circuits.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view of an example of a disk-type steam trap according to the present invention, and FIG. 2 is an enlarged view of the main part of FIG. 1. 1... Trap body, 2... Inlet port, 3
...Outlet port, 10...Sheet member, 12...
Annular groove, 13... Inner ring seat, 14... Outer ring seat, 15
... Inflow hole, 16 ... Outflow hole, 17 ... Placement surface (lower surface), 18 ... Sealing groove, 20 ... Gasket,
22... Elastic part, 23... Inner circumferential groove, 30... Cap, 32... Transformation chamber, 40... Disk, 50
……cover.

Claims (1)

[Claims for Utility Model Registration] A trap body 1 having an inlet port 2 and an outlet port 3, and a ring seat 13, 14 which is incorporated into the trap body 1 and has double inner and outer rings divided on the same plane by an annular groove 12. An inflow hole 15 communicating with the inlet port 2 is formed inside the inner ring seat 13, and an outflow hole 1 communicating with the outlet port 3 is formed at the bottom of the annular groove 12.
6 and the inner and outer ring seats 13,
14 and between the sheet member 10 and the variable pressure chamber 32
a cap 30 that is covered to form a trap body 1; a flat disk 40 that is disposed within the variable pressure chamber 32 and can be commonly seated on the inner and outer ring seats 13 and 14; and a mounting surface of the seat member 10 on the trap body 1. and a gasket 20 made of polytetrafluoroethylene resin or its analog, which is tightly fitted into an annular sealing groove 18 formed around at least the inlet port 15, and the gasket 20 is made of polytetrafluoroethylene resin or a similar material. In a disk type steam trap in which the flow of condensate flowing through the outflow hole 16 to the outlet port 3 is controlled by a disk 40, the inner surface of the inflow hole 15 and the side closer to the inner ring seat 13 than the mounting part of the gasket 20 is At a nearby location,
An inner circumferential groove 23 whose bottom diameter is approximately the same as the outer diameter of the gasket 20 is formed on the inner circumferential side of the gasket 20, and has a substantially L-shaped cross section that can be elastically deformed in the direction of the inner ring seat 13 as the gasket 20 expands in volume. A disc type steam trap characterized in that an elastic part 22 is formed integrally with a sheet member 10.