JPH11201320A - Dew formation preventing device for valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dew formation preventing device for a valve, efficiently preventing dew formation by lowering heat conduction by preventing a convection phenomenon arising in a space in a heat insulator, and improving workability of winding a cold insulator. SOLUTION: In a valve having a stem 14 projecting from the valve, a flange 16 for attaching a driving device on an outer end of a valve shaft sleeve 15 surrounding the stem 14, and a valve element 13 opened/closed by rotation of the stem 14, the driving device 17 for the stem 14 is attached to the flange 16 via a heat insulator 20, the heat insulator 20 is cylindrical and has a convection preventing plate installed in an opposed space of the flange 16 and the driving device 17 in the inside, and spaced apart from both, in order to section the opposed space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dew condensation preventing device for a valve, and more particularly, to an end portion of a valve shaft cylinder of a rotary valve such as a butterfly valve or a ball valve used in a chilled water line of a building air conditioner or an exposed area of a driving device. The present invention relates to a dew condensation preventing device for a valve, which prevents dew condensation in a valve.

[0002]

2. Description of the Related Art Condensation is the condensation of water in the air and the appearance of water droplets. Therefore, when a low-temperature fluid such as cooling or freezing is supplied to a pipe equipped with a rotary valve such as a butterfly valve. When the temperature of the outer surface of the pipe or the rotary valve becomes lower than the dew point under the condition of the temperature and humidity of the atmosphere, dew condensation occurs on the outer surface. Therefore, in general, the outer periphery of the cold water piping and the rotary valve is covered with a cooling material so as to prevent direct contact with the atmosphere so that dew condensation does not occur in this portion.

However, this type of rotary valve, such as a butterfly valve, is provided with a drive device for an actuator such as an electric / pneumatic device or a drive device for a manual gear mechanism so as to protrude above the valve perpendicular to the pipe. The operation of the drive unit is not affected. For this reason, it is usual that the valve stem of the valve body is formed to be long so that the valve stem at the flange portion and the cooling material around which the drive device is wound are exposed to the outside.

However, the cold heat from the cold water is transmitted through the stem of the rotary valve such as a butterfly valve and the valve stem which is the neck, easily reaches the flange portion, and when a drive device such as a gear mechanism is directly mounted on the flange portion, Condensation forms on exposed parts that come into contact with outside air. Since there is a problem that rust is generated inside the drive device due to the dew condensation, water droplets flow, and the surroundings are soiled, various countermeasures have been proposed to prevent this.

For example, in the structure shown in FIG. 7, a flange portion 3 is provided at an outer end of a valve stem 2 on which a stem 1 of a butterfly valve is mounted, and a heat insulating material 5 having a space 4 on the inner periphery of the flange portion 3. The drive device 6 of the manual gear mechanism is fixed with the mounting bolts 7 with the interposition of the cooling mechanism 8 around the butterfly valve. The heat insulating material 5 needs a thickness of 10 mm or more to reduce heat conduction, but on the other hand, the space 4 is formed in order to reduce the thickness of the inner periphery of the heat insulating material 5 to prevent shrinkage due to molding. Provided.

In Japanese Patent Publication No. 6-78789, a gear is fixed on a flange provided at an outer end of a valve stem via a heat insulating plate, and a heat insulating cover is further provided around the outer periphery of the valve stem. There is also proposed a structure in which dew condensation is prevented by applying a coating.

Further, in the structure shown in FIG. 8, a connecting flange 9 made of a heat-insulating resin is fixed to the outer end of the valve shaft insertion portion 2a through which the stem 1 is inserted. 6 is fixed with mounting bolts 7a, and the portion under the connecting flange 9 is wound around with the cold insulator 10 (see Japanese Patent Application Laid-Open No. 9-100946).

[0008]

However, the structure shown in FIG. 7 has been devised to reduce the amount of heat transmitted through each component with the heat insulating material 5 interposed therebetween, but the structure between the stem 1 and the space 4 is the same. As shown by the arrows in the figure, air convection occurs, and there is a problem that sufficient heat insulation effect cannot be obtained due to the convection, and the exposed driving device 6 is easily dewed. As a result, it is necessary to make the heat insulating material 5 thick. There was also.

In the structure disclosed in Japanese Patent Publication No. Hei 6-78789, it is necessary to attach a shielding cover separately from the heat shield plate around the outer periphery of the valve shaft cylinder. Not only must a cover be prepared, but also the number of parts increases, which in turn increases costs.

Further, the structure shown in FIG. 8 is a structure in which it is not necessary to wind the portion of the connecting flange 9 with a cold insulator.
Since the hollow shape of the cold insulator 10 is complicated and interference between the mounting bolt 7a and the cold insulator 10 occurs, the cold insulator 1
There is a problem that the work of winding 0 is troublesome.

The present invention has been developed in view of the conventional problems, and an object of the present invention is to prevent the convection phenomenon occurring in the space of the heat insulating material and to reduce the heat conduction to thereby efficiently dew condensation. Another object of the present invention is to improve the workability of the work by winding the heat insulating material.

[0012]

In order to achieve the above-mentioned object, a dew condensation preventing device for a valve according to the present invention has a stem protruding from a valve, a drive shaft mounting flange surrounding the stem, and a driving device mounting flange. In the valve whose valve body opens and closes due to the rotation of the valve, a stem driving device is attached to the flange via a heat insulating material, and the heat insulating material is cylindrical, and is separated from the both in the space inside the flange and the driving device facing each other. Thus, a convection prevention plate for dividing the facing space is provided.

In this case, the convection prevention plate is formed integrally with the heat insulating material, or a separate convection prevention plate is attached to the heat insulating material.
In addition, the heat insulating material is made substantially rectangular, and bolt through holes are provided at four corners, and the drive device is fixed to the flange through these holes with bolts. In addition, by providing a skirt portion surrounding the outer periphery of the flange with a space at the lower end of the heat insulating material, the workability of winding the cold insulating material is improved. Further, the dew condensation preventing device for a valve according to the present invention can be applied to a rotary valve such as a butterfly valve or a ball valve.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the dew condensation preventing device for a rotary valve according to the present invention is applied to a butterfly valve will be described with reference to the drawings. 1 to 6, a rubber seat ring 12 is mounted on the inner peripheral surface of a cylindrical body 11, and a valve body (disc) 13 is rotatably provided in the seat ring 12 and provided on the disc 13. The stem 14 to the body 1
1 and is mounted on a valve stem 15 integrally formed. In addition, this valve stem cylinder 15 is used for the
It may be provided separately from and fixed to the body 11.

Further, a mounting flange 16 formed in a rectangular, circular or elliptical shape is formed at the outer end of the valve stem 15.
An automatic driving device such as electric, hydraulic, pneumatic, etc., or a driving device 17 such as a manual gear mechanism having a handle 17a as shown in the drawing is mounted on the flange 16 and inserted through an insertion hole 18 formed in the flange 16. The drive device 17 is fixed on the flange 16 via a heat insulating material 20 by a bolt 19. The flange 16 may have a structure provided separately from the valve stem 15 other than the above example.

Further, the heat insulating material 20 is a molded product of a synthetic resin, and an appropriate material having a low thermal conductivity such as polypropylene, ABS resin, Duracon, or nylon is used. Further, the heat insulating material 20 has a substantially polygonal cylindrical shape, is provided with holes 21 for bolt penetration at the four corners, and is provided on the lower end side so as to hang a skirt portion 22 having an increased diameter. The skirt portion 22 is provided so as to surround the outer periphery of the flange 16 with a space therebetween to form a heat insulating space 23. The heat insulating material 20 has a shape corresponding to the shape of the flange 16 and is formed in a tubular shape appropriately corresponding to the shape.

An intermediate step 2 is provided on the inner periphery of the heat insulating material 20.
A convection prevention plate 25 having an insertion hole 25 a is inserted into the intermediate step portion 24, and a space 2 facing the flange 16 and the driving device 17 is provided above and below the convection prevention plate 25.
6, 27 are provided respectively. This convection prevention plate 25
Is preferably excellent in heat insulation. In this example, styrene foam is used, but other synthetic resins may be used. In this case, the convection prevention plate 25 is provided separately, but an integral molded product may be used by using the same material as the heat insulating material 20.

In FIG. 2, reference numeral 28 denotes a flange outer diameter portion, and reference numeral 29 denotes a cooling material wound around a pipe or a rotary valve such as a butterfly valve. The cooling material 29 has a shape covering the position of the flange 16. It is wrapped, and the heat insulating material 2
Since the flange 16 is covered by the side surface of the flange 16 and the heat insulating space 23 provided by the skirt portion 22 provided on the outer periphery, the contact width with the outer peripheral portion of the cold insulation increases, and the outer periphery of the cold insulator 29 is hollowed out. The shape can be easily formed, and there is no interference with the bolt 19, so that the workability by winding the cold insulator 29 is improved.

According to the above example, the stem 14 and the heat insulating material 2
By inserting the convection prevention plate 25 having a low thermal conductivity between 0 and 0, the space on the inner peripheral surface of the heat insulating material 20 is thermally insulated and bisected, thereby preventing a convection phenomenon that may occur in this space. Therefore, it is difficult for the cold heat of the low-temperature fluid flowing in the pipe to be transferred from the stem 14 to the flange 16 and the drive device 17, and therefore, the dew condensation phenomenon can be prevented.

Further, the convection preventing plate 25 is provided in the spaces 26, 2
Since it is separated from the flange 16 and the driving device 17 through the space 7, heat conduction is also suppressed by the spaces 26 and 27, so that dew condensation at this portion can be prevented and the heat insulating material 20 can be made thin. Becomes possible.

[0021]

As is apparent from the above, according to the present invention, the convection preventing plate is provided in the space facing the flange and the drive unit inside the tubular heat insulating material, separated from the both. Since convection does not occur inside the heat insulating material, heat conduction is suppressed to a very low level, and the dew condensation phenomenon between the driving device and the flange portion can be efficiently prevented.

Further, since the skirt portion surrounding the outer periphery of the flange is provided with a space at the lower end of the heat insulating material, it is easy to apply the cold insulating material. Since the contact width increases, there is an effect that the workability of the construction of the cold insulator is remarkably improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a dew condensation preventing device for a butterfly valve according to the present invention.

FIG. 2 is a partially cutaway front view showing a dew condensation preventing device for a butterfly valve according to the present invention.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a plan view in which a convection preventing plate is provided on the heat insulating material of FIG. 3;

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a bottom view of FIG. 4;

FIG. 7 is a partial sectional view showing an example of a conventional dew condensation preventing device for a butterfly valve.

FIG. 8 is a partial sectional view showing another example of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Valve body (disc) 14 Stem 15 Valve stem 16 Flange 17 Drive device 19 Bolt 20 Heat insulating material 21 Bolt through hole 22 Skirt part 23 Heat insulating space 25 Convection prevention plate 26, 27 Space

Claims (5)

[Claims] 1. A valve in which a stem protrudes from a valve and has a driving device mounting flange at an end of a valve stem surrounding the stem, and the valve is opened and closed by rotation of the stem. A dew-condensation prevention device for a valve in which a device is mounted, and a heat insulating material is cylindrical, and a convection prevention plate is provided in a space inside the flange and the drive unit, which is separated from the both, and separates the space. 2. The dew condensation preventing device for a valve according to claim 1, wherein a convection preventing plate is integrally formed with the heat insulating material. 3. The dew condensation preventing device for a valve according to claim 1, wherein the heat insulating material is made substantially rectangular, and bolt driving holes are provided at four corners, and the driving device is bolted to the flange through the holes. 4. The dew condensation preventing device for a valve according to claim 1, further comprising a skirt portion surrounding the outer periphery of the flange with a space provided at a lower end of the heat insulating material. 5. The dew condensation preventing device for a valve according to claim 1, wherein the valve is a butterfly valve.