JPH0129337Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a large capacity steam valve.

In conventional large capacity steam valves, for example, the first
As shown in FIG. By sequentially opening a large number of drilled small holes, the rate of increase in opening area for the lift is reduced, and in a large lift state, the large window of the muffler 7 is opened to increase the rate of increase in area.
It has flow characteristics as shown in FIG.

Therefore, in this type of steam valve, in a small lift state, the valve 1 opens a large number of small holes in the muffler 7, so if the valve 1 shifts to one side, the valve 1 opens many small holes in the muffler 7. The pressure around the valve increases and the valve is pushed to the opposite side.

This will cause the area around the small hole in the muffler on the opposite side to be blocked, increasing the pressure.
In this way, when the valve 1 is shifted to one side, the surrounding pressure distribution changes, and the resulting force acts as a restoring force against the one-sided valve, making the valve more likely to vibrate, and furthermore, the tip of the muffler 7 opens in the middle. Due to the large windows, which are supported by thin struts between the windows, the valves are susceptible to damage due to vibration.

Furthermore, since the muffler 7 is supported by the bonnet 4, clearances are provided in the axial and radial directions to prevent excessive thermal stress from occurring due to restraint of thermal expansion when a transient temperature difference occurs. Since the muffler 7 is fitted into the valve seat, when the valve 1 starts to open, the pressure at the inner peripheral pocket at the tip of the muffler 7 acts in the same manner as described above, causing the valve 1 to vibrate.

Here, 2 is the valve stem, 3 is the bottom member of the valve 1, and the valve stem 2
5 is a bush that slidably supports the valve stem 2, 6 is a plurality of seal rings fitted around the outer circumference of the skirt of the valve 1, and 8 is a guide metal.

The present invention was proposed in view of the above circumstances, and an object of the present invention is to provide a strong, large-capacity steam valve that prevents vibration and damage to the valve.

To this end, the present invention provides a large-capacity steam valve that has a relatively small area increase rate at relatively small lifts and a relatively large area increase rate at relatively large lifts. A short cylindrical protrusion that protrudes from the valve body and surrounds the outer periphery of the tip of the valve body in the closed state, the upper end of which faces the bonnet and forms a large steam passage port, and the short cylindrical protrusion has a radius. It is characterized by having a large number of small-diameter steam flow holes drilled in the direction.

An embodiment of the present invention will be explained with reference to the drawings.
FIG. 5 is a longitudinal sectional view thereof.

In the above figure, the same symbols as in FIG. Similar to the muffler 7 shown in the figure, a large number of small holes are bored in the radial direction.

According to such a structure, the low lift portion of the muffler 7 shown in FIG. Even if the valve were to collide, no large stress would be generated, and no vibration or damage would occur.

In short, according to the present invention, in a large-capacity steam valve that has a relatively small area increase rate at a relatively small lift and a relatively large area increase rate at a relatively large lift, the valve seat is surrounded and integrated. a short cylindrical protrusion that protrudes from the valve body and surrounds the outer periphery of the tip of the valve body in the closed state, and whose upper end faces the bonnet to form a large steam passage port; The present invention is industrially very useful because it provides a large capacity steam valve that is quiet and has a long service life by providing a large number of small diameter steam flow holes drilled in the radial direction.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a known large capacity steam valve;
Figure 2 is a cross-sectional view taken along - in Figure 1;
The figure is a partial front view of the muffler in Figure 1 as seen from the arrow, and
This figure is a flow rate characteristic diagram of the steam valve shown in FIG. 1, and FIG. 5 is a longitudinal sectional view showing one embodiment of the present invention. 1... Valve, 2... Valve stem, 3... Holding money, 4...
Bonnet, 5...Button, 6...Seal ring, 7a...Valve seat.

Claims (1)

[Scope of utility model registration request] In a large-capacity steam valve that has a relatively small area increase rate at relatively small lifts and a relatively large area increase rate at relatively large lifts, the valve seat is integrally protruded surrounding the valve seat to close the valve. In this state, surrounding the outer periphery of the tip of the valve body, there is a short cylindrical protrusion whose upper end faces the bonnet and forms a large steam flow opening, and a radially perforated part in the short cylindrical protrusion. A large-capacity steam valve characterized by having a large number of small-diameter steam flow holes.