JPH0960764A - Dew condensation preventing device for butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dew condensation preventing device capable of effectively preventing the dew condensation on the surface of a valve shaft tube and having a simple structure at a low cost. SOLUTION: A heat insulating resin film 6 is fitted through a heat insulating space to the outer peripheral face of a valve shaft tube 4 extended outward in the radial direction from the valve main body 3 of a butterfly valve 1, heat insulating treatment is applied to the valve shaft tube 4, and the dew condensation on the surface of the valve shaft tube 4 can be prevented.

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 butterfly valve, and more particularly to a dew condensation occurring on the surface of a valve shaft cylinder due to a temperature difference between a fluid whose flow rate is controlled by the butterfly valve and the atmosphere. And a device for preventing the above.

[0002]

2. Description of the Related Art Condensation occurs on the surface of a pipe, such as a pipe for cooling or freezing, through which a low temperature fluid flows, due to a temperature difference between a fluid flowing through the pipe and the atmosphere, and the same Condensation also occurs on the surface of the butterfly valve installed in the pipe to control the flow rate of

Therefore, conventionally, as shown in FIG. 3, for example, a valve shaft cylinder B extending diametrically outward from the valve body A is made of stainless steel separate from the valve body A, and By friction-welding the valve shaft cylinder B and integrally connecting them,
The surface of the valve stem B is prevented from dew condensation (see Japanese Patent Laid-Open No. 7-14279). In FIG. 3, C is a valve element, D is a seat ring, and E is an actuator coupled to the valve element C via a valve rod F. Normally, the valve body A is heat-insulated by using a heat insulating material for piping not shown. are doing.

However, when a valve shaft cylinder B made of stainless steel is prepared separately from the valve main body A and these are frictionally pressure-bonded and integrally connected, it is necessary to use expensive stainless steel and the manufacturing process. However, the manufacturing cost of the butterfly valve is high because of the complexity of the above.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive dew condensation preventing device having a simple structure which can effectively prevent dew condensation on the surface of the valve shaft cylinder.

[0006]

The present invention is characterized in that a heat insulating resin coating is attached to an outer peripheral surface of a valve shaft cylinder extending radially outward from a valve body via a heat insulating space.

Further, according to the present invention, a plurality of ribs are formed on the outer peripheral surface of the valve shaft cylinder along the axial direction of the valve shaft cylinder, and the tips of the ribs are brought into contact with the inner peripheral surface of the heat insulating resin coating for heat insulation. Secure space,
Alternatively, it is characterized in that the heat insulating resin coating is constituted by a plurality of resin pipes divided by a dividing surface along the axial direction of the valve shaft cylinder.

[0008]

According to the dew condensation preventing device of the butterfly valve of the present invention, the following effects can be obtained.

1. Since the heat insulating resin coating is attached to the outer peripheral surface of the valve shaft cylinder through the heat insulating space, the atmosphere does not directly contact the surface of the valve shaft cylinder, and heat is applied to the heat insulating resin coating by the heat insulating function of the heat insulating space. It becomes difficult to be transmitted. Therefore, the dew condensation on the surface of the valve shaft cylinder can be surely prevented, and the dew condensation on the surface of the heat insulating resin coating is also prevented.

[0010] 2. When the tip of the rib provided on the outer peripheral surface of the valve shaft cylinder is brought into contact with the inner peripheral surface of the heat insulating resin coating to secure a heat insulating space, the rib forms a plurality of heat insulating spaces to suppress internal heat convection. In addition, since the heat insulating space can be reliably formed, the effect of preventing dew condensation becomes higher.

3. When the heat insulation resin coating is composed of a plurality of resin pipes divided by the dividing surface along the axial direction of the valve cylinder, an inexpensive resin pipe can be used as the heat insulation resin coating and the workability of installing the resin coating can be improved. Is higher,
It is possible to suppress an increase in the manufacturing cost of the dew condensation prevention device for the butterfly valve.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the figure
(1) shows a butterfly valve provided with a dew condensation prevention device according to the present invention, and extends outward in the diametrical direction on the outer peripheral surface of a valve body (3) having a valve body (2) inside. The valve shaft cylinder (4) is integrally provided.

On the outer peripheral surface of the valve shaft cylinder (4), a plurality of ribs (5) are provided so as to project along the axial direction of the valve shaft cylinder (4). And
By attaching a heat insulating resin coating (6) having a semicircular cross section obtained by dividing the resin pipe in two by a dividing surface along the axial direction to the valve shaft cylinder (4) from both sides, a heat insulating space is provided on the outer periphery of the valve shaft cylinder (4). (7) is formed. Also, the tip of each rib (5) is brought into contact with the inner peripheral surface of the heat insulating resin coating (6), and an adhesive tape (not shown) or a fastening band (not shown) is wound around the surface of the heat insulating resin coating (6). Various fastening processes are applied to prevent the heat insulating resin coating (6) from falling off. (8) is a seat ring attached to the inner peripheral surface of the valve body (3), (9) is a valve rod, and (10) is an actuator mounting plate (not shown).

That is, since the heat insulating resin coating (6) is attached to the outer periphery of the valve stem (4) through the heat insulating space (7), the valve stem (4)
The atmosphere does not come into direct contact with the surface of the insulation space (7)
The heat insulation effect makes it difficult for heat to be transferred to the heat insulation resin coating (6). Therefore, the dew condensation on the surface of the valve shaft cylinder (4) can be surely prevented, and the dew condensation on the surface of the heat insulating resin coating (6) can be prevented.

Further, as in this embodiment, the tips of the ribs (5) provided on the outer peripheral surface of the valve shaft cylinder (4) are brought into contact with the inner peripheral surface of the heat insulating resin coating (6) so that the heat insulating space (7) is formed. When the partition is divided into a plurality of sections, the heat insulation resin coating (6) can be easily and surely fixed by using the rib (5) as a support, and the valve stem (4) is reinforced by the rib (5). In addition, the wall thickness of the valve stem (4) can be reduced to reduce the weight and heat capacity. Further, when the rib (5) is provided and the heat insulating space (7) is divided into a plurality of sections as in the present embodiment, the heat convection of the air inside the heat insulating space (7) is suppressed and the heat insulating space (7) is suppressed. Secure the thickness of (7)
Since the variation in the heat insulation function due to (7) can be reduced, the effect of preventing dew condensation is further enhanced, but the rib (5) is not always necessary.

Furthermore, when the heat insulating resin coating (6) is constructed by combining a plurality of resin pipes divided by the dividing surface along the axial direction of the valve shaft cylinder (4) as in this embodiment, it is commercially available. Inexpensive resin pipe can be used as the heat insulating resin coating (6), and the workability of attaching the heat insulating resin coating (6) is improved, so the increase in manufacturing cost due to the addition of the dew condensation prevention device is suppressed. It is possible, but it is not always necessary to use a resin pipe, and a resin sheet is wrapped around it to create a heat insulation space (7)
Can also be formed.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an embodiment of a butterfly valve provided with a dew condensation preventing device according to the present invention.

FIG. 2 is a horizontal cross-sectional view of the valve shaft cylinder portion shown in FIG.

FIG. 3 is a longitudinal sectional view of a conventional example.

[Explanation of symbols]

 (1) Butterfly valve (2) Valve body (3) Valve body (4) Valve shaft cylinder (5) Rib (6) Insulating resin coating (7) Insulating space (8) Seat ring (9) Valve stem (10) Mounting Board

Claims (3)

[Claims] 1. A dew condensation prevention device for a butterfly valve, wherein a heat insulating resin coating is attached to an outer peripheral surface of a valve shaft cylinder extending radially outward from a valve body via a heat insulating space. 2. A heat insulating space is ensured by forming a plurality of ribs along the axial direction of the valve shaft cylinder on the outer peripheral surface of the valve shaft cylinder and abutting the tips of the ribs on the inner peripheral surface of the heat insulating resin coating. The dew condensation preventing device for a butterfly valve according to claim 1, wherein 3. The butterfly valve according to claim 1, wherein the heat insulating resin coating is constituted by a plurality of resin pipes divided by a dividing surface along the axial direction of the valve shaft cylinder. Dew condensation prevention device.