JPH0526997B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in pressure-responsive valves such as safety valves used for refrigerant control in refrigeration equipment used in air conditioners and the like.

Construction of a conventional example and its problems A safety valve shown in FIG. 1 will be described as a conventional pressure-responsive valve of this type.

Reference numeral 1 denotes a safety valve, and a diaphragm 4 is provided between an upper casing 2 and a lower casing 3, and the outer peripheral ends of each are hermetically joined by arc welding or the like to form an outer shell 5. A valve device 7 is provided in the valve chamber 6 formed by the diaphragm 4 and the lower casing 3.
It has an inlet pipe 8 communicating with the valve device 7 and an outlet pipe 9 on the side opposite to the valve chamber 6 of the valve device 7. An adjustment chamber 10 formed by the diaphragm 4 and the upper casing 2 includes a bias spring 11 and an adjustment screw 12. In other words, in the relationship between the pressure P of the valve chamber 6, the effective area A of the diaphragm 4, the biasing force F of the bias spring 11, and the repulsive force R of the diaphragm 4 toward the valve chamber 6, P>(F+R). /A, the valve device 7
The circuit is opened, and the refrigerant flows from the inlet pipe 8 to the valve chamber 6 to the valve device 7 to the outlet pipe 8.

In this type of pressure-responsive valve, thermal expansion occurs in the welded portions of the diaphragm 4, upper casing 2, and lower casing 3 during arc welding. As is well known, the diaphragm 4 has been heat-treated and is made of a different material from the upper and lower casings 2 and 3, so as shown in Figure 2, the diaphragm 4 is in its welded state (double-dashed line in Figure 2). is different from before welding (solid line in Figure 2),
The outer peripheral ends of the upper and lower casings 2 and 3 are shaped to protrude from the outer peripheral end of the diaphragm 4. In this state, the upper and lower casings 2 and 3 are arc welded.
and the diaphragm 4 are melted and formed integrally. Next, the process after welding is completed will be explained.

As shown in Figure 3, the shape after welding (solid line in Figure 3) is compared to the shape before welding (double-dashed line in Figure 3).
The upper and lower casings 2 and 3 return to the same shape as before welding, but during welding, the diaphragm 4 whose outer peripheral edges are melted together with little thermal expansion shrinks by the same amount as the upper and lower casings 2 and 3. occurs. Therefore, the diaphragm 4 is subjected to stress strain in the inner circumferential direction, and the bead portion 4a of the diaphragm 4, which undergoes pressure deformation, changes shape, and the center surface 4 of the diaphragm 4
b is from the position before welding (solid line in Figure 3) downwards (third position).
(Double-dashed line in the figure) changes. Amount of change due to this welding x
are the thermal expansion coefficients and plate thicknesses of the upper and lower casings 2 and 3,
It varies due to subtle fluctuations in the amount of arc energy, etc., and the amount of change x is
There will be a variation of about 0.1mm to 0.4mm. Therefore,
If the displacement amount of the diaphragm 4 required to open and close the valve device 7 of the safety valve 1 is designed to be 0.5 mm, the actual absolute displacement amount of the diaphragm 4 is 0.5 mm ~
Due to the variation of 0.8 mm, diaphragm 4, which has a very high displacement, is not guaranteed for reliability.
However, there were problems in that it was necessary to control the material of the upper and lower casings 2 and 3, arc welding conditions, etc. very strictly.

Purpose of the Invention In view of the above problems, the present invention prevents changes in the diaphragm due to welding even if there are variations in each component or in the welding conditions, and enables prevention of excessive quality of the diaphragm and easy assembly. The purpose is to

Structure of the Invention In order to achieve the above object, a pressure-responsive valve according to the present invention includes a diaphragm having a flange portion on the outer periphery and a substantially constant plate thickness, and a diaphragm formed by bending the diaphragm and provided on the flange portion. It has an annular groove, and a valve device that adjusts the opening degree by displacement of an upper casing, a lower casing, and the diaphragm that constitute an outer shell, and a storage part for the annular groove is provided in either the upper or lower casing, A space is provided between the inner wall of the storage part and the bottom outer wall of the annular groove part, and the upper and lower casings are heated and joined at an outer side of the position where the storage part is provided,
This prevents stress strain due to thermal expansion during welding from reaching the bead of the diaphragm.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings (FIGS. 4 to 6).

21 is a safety valve which is a safety response valve. 22 is an upper casing, 23 is a lower casing, and 24 is a diaphragm having a substantially constant plate thickness.
The outer peripheral end of 4a is melted and integrally formed by arc welding. A threaded portion 25 is formed at the upper center of the upper casing 20, and the center 2 of the diaphragm 24
A spring A26 whose lower end is in contact with the upper surface of 4b is disposed. The threaded portion 25 has an adjustment screw 2 whose lower surface is in contact with the upper end of the spring A26.
7 are screwed together. Atmospheric pressure acts on the inside of the adjustment chamber 28, which is constituted by the upper casing 22 and the diaphragm 24, through a through hole 27a provided in the adjustment screw 27.

On the other hand, a valve device 30 is provided in a valve chamber 29 composed of a lower casing 23 and a diaphragm 24 . 31 is a valve seat, 32 is a valve body, and 33 is a spring B. The valve seat 31 is joined to the lower casing and communicates with the outlet pipe 34. Spring B3
3 has its lower end engaged with the outer periphery of the valve seat 31 and its upper end engaged with the valve body 32, and the upper surface of the valve body 32 is brought into contact with the lower surface of the center 24b of the diaphragm 24.

Further, the lower casing 23 is provided with an inlet pipe 35 open to the valve chamber 29. Therefore, the valve chamber 29
When the internal pressure exceeds the set pressure adjusted by the spring A26, the diaphragm 24 is displaced upward, the valve device 30 is opened, and the flow from the inlet pipe 35 to the outlet pipe 34 is enabled. In addition, 36 is a stopper, which is provided between the lower end of the spring A26 and the upper surface of the diaphragm center 24b, and when the diaphragm 24 is displaced upward, the upper casing 24
It is to be locked onto the top surface of 2.

Diaphragm flange 24 of diaphragm 24
An annular groove 24c is located approximately in the center of the diaphragm 2.
4, and is housed in a housing portion 23b (hereinafter referred to as groove 23b) formed approximately at the center of the lower casing flange 24a of the lower casing 23. A space is provided between the bottom outer wall of the annular groove 24c and the bottom inner wall of the groove 23b. Further, the outer side wall of the annular groove portion 24c is in contact with the inner wall of the groove 23b. Diaphragm flange 24
The inner side 24d of the annular groove 24c of a is connected to the lower surface of the upper casing flange 22a and the lower casing flange 2.
It is fixed on the upper surface of the inner flange 23c of the groove 23b of 3a.

Next, arc welding during assembly of the safety valve, which is a pressure-responsive valve having the above structure, will be explained. The shapes of the upper casing flange 22a, diaphragm flange 24a, and lower casing flange 23a before welding are as shown in broken lines in FIG.
Each outer peripheral edge is located at almost the same position. When arc welding is performed in this state, each component thermally expands due to the arc energy, resulting in the shape shown by the solid line in FIG. 5. At this time, each part has a slightly different coefficient of thermal expansion, degree of temperature rise, etc., so each outer peripheral end is in a completely different position. Since each outer peripheral end is melted and integrated as it is, the shape after welding is completed is the shape shown by the solid line in FIG. 6. The shape after welding is different from the shape before welding (broken line in FIG. 6), and in particular, the diaphragm flange 24a, which has a small coefficient of thermal expansion, contracts inward at a large rate. Due to the stress strain caused by this contraction, the diaphragm flange 24
a is contracted inward, but the annular groove 24c
By contracting in the radial direction, the stress strain is absorbed, and the stress strain is not transmitted to the inner side 24d of the annular groove portion 24c. Therefore, the diaphragm 24
There is no thermal effect due to welding on the central surface 24b, and the shape as a single unit is as designed. That is, even if the shape after thermal expansion during welding (solid line in Figure 5) is slightly different, the shape after welding (solid line in Figure 6), especially the center surface 24b of the diaphragm 24, does not change at all from before welding. The amount of displacement that determines the reliability of the diaphragm 24 is also as designed.

Effects of the Invention As is clear from the above description, the pressure-responsive valve according to the present invention absorbs the stress strain after assembly caused by the difference in thermal expansion of each component during arc welding in the annular groove, and the center surface of the diaphragm There is no deformation due to the heat effect of arc welding, and material variations and
There is no need to consider variations in welding conditions. In addition, since there is no deformation due to heat effects, the amount of displacement of the tire flam remains the same as the part design.
Unlike the conventional tire flam, there is no need to create a tire flam with an excessive margin in consideration of deformation due to thermal effects, and it is possible to easily assemble and guarantee high quality.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a safety valve, which is a conventional pressure-responsive valve, Figure 2 is an enlarged sectional view of the main part of Figure 1 during welding, and Figure 3 is an enlarged sectional view of the main part of Figure 1 after welding. , Fig. 4 is a sectional view of a safety valve showing an embodiment of the present invention, Fig. 5 is an enlarged sectional view of the main part of Fig. 4 during welding, and Fig. 6 is an enlarged main part of Fig. 4 after welding. FIG. 21...Pressure responsive valve (safety valve), 22...Upper casing, 23...Lower casing, 24...Diaphragm, 24a...Diaphragm flange, 2
4c... annular groove portion, 30... valve device, 23b...
Locking signal (concave groove), 24d...inner side of the annular groove.

Claims (1)

[Scope of Claims] 1. A diaphragm having a flange portion on its outer periphery and having a substantially constant plate thickness, an annular groove formed by bending the diaphragm and provided in the flange portion, and an upper casing constituting an outer shell; a lower casing and a valve device that adjusts the degree of opening by displacement of the diaphragm; a storage section for the annular groove is provided in either the upper or lower casing; an inner wall of the storage section and a bottom of the annular groove; Create a space between the outer wall and
A pressure-responsive valve in which the upper and lower casings are heat-joined at an outer side of a position where the storage portion is provided. 2. The pressure-responsive valve according to claim 1, wherein the storage portion is a groove.