JPS597078B2 - Disc steam trap - Google Patents

Description

[Detailed description of the invention] The present invention relates to a disc steam trap.

In general, a disc-type steam trap has an inner annular valve seat A and an outer annular valve seat B that are concentric as shown in Fig. 1, and the valve disc C is placed on and off both valve seats A and H at the same time with extremely high precision. It has been processed.

However, when a disc-type steam trap with the structure shown in Figure 1 is used in a high-temperature, high-pressure steam system, the valve disc C
The pressure on the inlet D side of high temperature and high pressure acts from the central lower surface of the valve disk C, and the pressure on the variable pressure chamber E side acts on the outlet F side opening from the upper surface of the periphery of the valve disk C, so that the valve disk is shaped as shown by the two-dot chain line σ. It was curved, creating a small gap with the inner annular valve seat A, causing steam to leak.

This leakage action radially erodes the inner annular valve seat surface, causing an increase in the amount of leakage and a shortened lifespan.

In order to eliminate this leakage effect, it is known that the valve disk is made thicker to prevent curvature, or that a step is provided on the inner and outer annular valve seat surfaces in anticipation of the curvature of the valve disk.

However, if the valve disk is made thicker, the weight of the valve disk increases, resulting in insensitivity in operation or a sagging phenomenon at low pressures, and even a slight increase in the wall thickness cannot prevent the bending effect.

Further, in order to provide a step on the valve seat, it is necessary to set the step accurately in accordance with the operating pressure, which limits the operating pressure range and causes a dry firing phenomenon at low pressures, both of which pose practical problems.

The present invention has been made in view of the above circumstances, and aims to provide a disk-type steam trap that can act in a wide pressure range from high pressure to low pressure, has no leakage, and has a long life.

The above purpose is to create a variable pressure chamber with an inlet and an outlet communicating with each other, a valve disc disposed inside the variable pressure chamber, and an inner and outer space concentrically formed at the opening of the variable pressure chamber at the inlet and outlet so that the valve disc can be seated and taken off at the same time. A disc-type steam trap comprising an annular valve seat, the inner and outer annular valve seats being made of different metals so that the thermal expansion of the inner annular valve seat is greater than that of the outer annular valve seat. This can be achieved by

Here, the feature of the present invention is that the bending action of the valve disk due to steam pressure is absorbed by the step created by the thermal expansion of the inner and outer annular valve seats due to the heating action of the steam, and the bending action of the valve disk due to the steam pressure is absorbed by the step created by the thermal expansion of the inner and outer annular valve seats due to the heating action of the steam. In a wide range of
This is to prevent leakage.

As a means of joining a valve seat made of a different metal to the trap body,
Any method such as brazing, pressure welding, welding, etc. may be used, and in particular, friction welding, electron beam welding, etc. can provide a high quality joint and a good joint.

Furthermore, even if either the inner annular valve seat or the outer annular valve seat is molded integrally with the trap body, and the other annular valve seat is made of a metal different from the trap body and is joined to the trap body, Both the valve seat and the trap body may be made of different metals, and the inner and outer annular valve seats may be made of different materials by being joined to the trap body.

Furthermore, when increasing the level difference due to the difference in thermal expansion between the inner and outer annular valve seats, it is possible to avoid a decrease in strength by not only increasing the lift of the annular valve seat but also by embedding and joining the annular valve seat into the trap body. You can get a thicker lift.

Hereinafter, a detailed explanation will be given based on the illustrated embodiment.

In FIG. 2, reference numeral 1 denotes a trap body, and a top cover 2 is screwed onto it to form a trap housing.

Further, various gaskets may be interposed between the main body 1 and the upper lid 2.

Reference numeral 3 denotes a variable pressure chamber formed within the trap housing, and an inlet 4 and an outlet 5 communicate with each other through an inlet passage 6 and an outlet passage 7.

Reference numerals 8 and 9 denote an inner annular valve seat and an outer annular valve seat that are formed concentrically at the openings of the inlet passage 6 and the outlet passage 7 on the variable pressure chamber 3 side.

Here, the inner annular valve seat 8 is formed of a metal having a coefficient of thermal expansion larger than that of the outer annular valve seat 9 integrally formed with the main body 1, and is joined to the main body 1.

Reference numeral 10 denotes a disk placed in the variable pressure chamber 3 so as to be placed on and off at the same time as the inner and outer annular valve seats 8 and 9.

This disc-type steam trap is caused by pressure fluctuations within the variable pressure chamber 3 and pressure fluctuations caused by the fluid flowing between the inner annular valve seat 8 and the valve disc 10.
0 opening/closing action and automatically discharges condensate.

Here, when the disc type steam trap of the above embodiment is used in a high temperature and high pressure steam system, when the valve is closed,
The pressure difference between the inlet 4 side and the variable pressure chamber 3 side acts from the lower central surface of the valve disk 10, and the differential pressure between the variable pressure chamber 3 side and the outlet 5 side acts from the upper peripheral surface of the valve disk 10.
is curved as illustrated in FIG.

Further, the valve seat surfaces of the inner and outer annular valve seats 8 and 9, which were in the same plane as shown in FIG. 2 at room temperature, are heated by the high-temperature, high-pressure steam, and due to the difference in thermal expansion, a step is created as shown in FIG. 3.

At this time, the temperature distribution differs depending on the distance from the inlet passage 6, and the inner annular valve seat 8 is heated to a higher degree than the outer annular valve seat 9 and expands to a higher degree.

Therefore, if the curvature of the valve disk 10 is set to match the level difference between the inner and outer annular valve seats 8 and 9 depending on the temperature, it can be used in a wide pressure range from low pressure to high pressure without causing leakage. .

Moreover, FIGS. 4 to 6 show other embodiments in which the same effects as those described above can be obtained.

FIG. 4 shows another embodiment in which the inner annular valve seat 8a is integrally molded with the main body 1a, and the outer annular valve seat 9a is made of a metal having a smaller coefficient of thermal expansion than the inner annular valve seat 8a, and is joined to the main body 1a. shows.

In FIG. 5, both the inner and outer annular valve seats 8b and 9b are formed of different metals from the main body 1b, and are joined to the main body 1b.

Here, the inner annular valve seat 8b is made of a metal having a larger coefficient of thermal expansion than the outer annular valve seat 9b.

FIG. 6 shows that a groove is provided in the main body 1c to make the lift of the inner annular valve seat 8c larger than that of the outer annular valve seat 9c.
It is embedded and bonded.

As described above, the present invention absorbs the bending effect of the valve disk by the step difference in the valve seat surface due to the difference in thermal expansion between the inner and outer annular valve seats, and can be used in a wide range from low temperature and low pressure to high temperature and high pressure without causing leakage. We can provide long-life disc steam traps.

[Brief explanation of drawings]

FIG. 1 shows a conventional disk-type steam trap, FIG. 2 shows a disk-type steam trap according to an embodiment of the present invention, FIG. 3 is a main part diagram showing the operation of the embodiment of FIG.
FIG. 6 shows the main parts of another embodiment. 1, 1a, 1b, 1c are the main body, 2 is the upper lid, 3 is the transformation chamber,
4 is an inlet, 5 is an outlet, 6 is an inlet passage, 7 is an outlet passage, 8
, 8a, 8b, 8c are inner annular valve seats; 9. 9a, 9b
, 9c is an outer annular valve seat, and 10 is a valve disk.

Claims (1)

[Claims] 1. A variable pressure chamber with a communicating outlet, a valve disc disposed within the variable pressure chamber, and an inner and outer annular valve concentrically formed at the openings of the variable pressure chamber at the inlet and outlet so that the valve disks can be seated and unseated at the same time. A disc-type steam trap comprising an inner and outer annular valve seat made of dissimilar metals so that the thermal expansion of the inner annular valve seat is greater than that of the outer annular valve seat.