JPS6339764Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pressure regulating valve, particularly a direct acting pressure regulating valve with improved temperature characteristics.

In general, a pressure regulator or pressure control valve adjusts the pressure of the fluid passing through it to a lower, almost constant pressure, regardless of pressure fluctuations on the inlet side, when the pressure of the fluid passing through it is higher on its inlet side than on its outlet side. Many things that can be used are conventionally used. Among them, in the case of a direct-acting type with particularly quick response, if the ambient temperature at the location where this conventional pressure regulating valve is installed changes considerably, the pressure on the outflow side, that is, the set pressure, changes accordingly. Since it cannot be avoided, adjustments must be made each time, but this is considered a difficulty depending on the application.

This idea addresses the above-mentioned difficulties in conventional direct-acting pressure regulating valves, and improves the temperature characteristics of conventional ones by adding simple components. The purpose is to provide

Embodiments of this invention will be described below with reference to the drawings. The figure is a side sectional view of the device of this embodiment.

This device consists of a hollow cylindrical container 11 with an open bottom.
A cylindrical base 12 is screwed to the cylindrical base 12, and the cylindrical base 12 has a female threaded portion 1 to which fluid inflow and outflow pipes are respectively connected via pipe joints.
3 and 14 are provided, and the female threaded portion 13 is connected to the throttle valve portion 1.
5, the female threaded portions 14 are directly connected to the inside of the bellows 16, respectively. The bellows 16 is made of a thin plate of stainless steel, for example, and has a cylindrical concave shape at its center, and a cylindrical base 12 at the lower end surface of its outer periphery.
It is hermetically fixed to the upper surface of, for example, by brazing. And the cylindrical recess 17 of this bellows 16
contains a cylindrical block 18 made of plastic material, for example polypropylene material, and having a thickness h;
A coil spring 19 is housed thereon. The coil spring 19 acts as a compression coil spring when the spring presser 20 engaged with the upper part of the coil spring 19 is lowered by tightening the adjustment screw 21 screwed into the center of the upper part of the hollow cylindrical container 11. It's summery. This coil spring 1 acts as a compression coil spring by tightening the adjustment screw 21.
The elastic force generated in the bellows 16 acts on the bottom of the cylindrical recess 17 of the bellows 16 via the cylindrical block 18, and the bottom is pushed into the cylindrical base 12 against the elastic force of the bellows 16 generated at that time. Bring it close to the top.
The movable valve body of the throttle valve portion 15, that is, the ball 1
5', a transmission rod 22 is inserted between this ball 15' and the bottom of the cylindrical recess 17.
is housed in a conduit between the valve portion 15 and the internal space of the bellows 16 with a gap maintained between the inner circumferential surface thereof. In addition, a compression coil spring 2 is attached to the throttle valve portion 15 to lightly press the ball 15' against the valve seat.
3 is provided. Note that 24 is a lock nut, which is used to prevent the adjustment screw 21 from loosening, and 25 is an air vent, which is used to prevent the inner space 26 of the hollow cylindrical container 11 from becoming loose.
is maintained at atmospheric pressure at all times.

Next, the operation of this device will be explained. .

This device is connected to an inflow pipe and an outflow pipe of a fluid through pipe fittings screwed into the female threaded portions 13 and 14, respectively, and the fluid pressure _P1 in the inflow pipe is converted to the fluid pressure P1 in the outflow pipe. ₂
(Here, let P ₁ > P ₂ ) be adjusted.

It is assumed that the ball 15' of the throttle valve portion 15 is in contact with its valve seat, and the transmission rod 22 is in contact with the bottom surface of the cylindrical recess 17 of the bellows 16 and the ball 15'.

Now, loosen the lock nut 24 and adjust the adjustment screw 21.
is then locked with the lock nut 24, and the coil spring 19 is compressed via the spring retainer 20 as described above. In this case, if the amount of depression of the spring holder 20 is δ ₁ , the elastic force of the coil spring 19 generated by this depression is applied to the bellows 16 via the cylindrical block 18, so that the spring holder 20 is also compressed, and its cylindrical shaped recess 17
The bottom of the is pressed down. If this pushing down amount is δ ₂ , the net compression amount of the coil spring 19 is δ ₁ − δ ₂
, and if its spring constant is k ₁ , then the coil spring 19 will lead to the cylindrical block 18 and the bellows 16.
through the bottom of the cylindrical recess 17 of the transmission rod 22.
The downward force applied to the ball 15' of the ball valve portion 15 is k ₁ ·(δ ₁ -δ ₂ ), and this force causes the ball 15' to be separated from the valve seat and pushed downward by δ ₂ . On the other hand, the upward force acting on the ball 15' is the sum of p ₁ A acting from the inflowing fluid and k ₂ δ ₂ acting from the coil spring 23, assuming that its projected area is A. However, k ₂ is the spring constant of the coil spring 23. Since the above-mentioned downward force and upward force acting on the ball 15' naturally balance each other, _k1・_{( δ1} − _δ2 )= _p1A + _k2δ2
becomes.

As described above, since the ball 15' is pushed downward by δ _{2 ,} a corresponding annular gap is created between the ball 15' and the valve seat. Therefore, the fluid flowing in at a pressure _p1 passes through the annular gap and is subjected to a throttling action, thereby reducing the pressure to _P'1 . The fluid whose pressure has decreased to P′ ₁ is bellows 1
After filling the internal space of 6, it flows out to the outflow pipe through the aforementioned conduit. On the other hand, the pressure P' ₁ of the fluid filling the inside of the bellows 16 is
5, the pressure is higher than the pressure in the internal space 26 of the hollow cylindrical container 11, which is always kept at atmospheric pressure.
Bellows 16 is extended upward. If this amount of extension is δ ₃ , then the amount by which the ball 15' is pushed down by the transmission rod 22 is reduced to δ ₂ −δ ₃ , and the amount of compression of the coil spring 19 becomes δ ₁ −δ ₂ +δ ₃ .

Therefore, the upper force acting on the ball 15' at this time. Considering the balance of downward forces, k ₁ (δ ₁ −δ ₂
+δ ₃ )=p ₁ A+k ₂ (δ ₂ −δ ₃ ) holds true. In this case, the annular gap becomes narrower due to the ball 15' being pushed up by δ ₃ , so the inflowing fluid passing through this annular gap is further throttled, and the pressure becomes p″ ₁ (p゜₁ < p By repeating this process in _a short time, the fluid pressure inside the bellows ₁₆ becomes constant corresponding to the amount of depression δ ₁ of the spring retainer 20 by tightening the adjustment screw 21. The pressure in _the outflow pipe is adjusted to this constant pressure _p2 .

In this way, the fluid pressure in the outflow line is regulated to a set pressure p ₂ that is lower than the fluid pressure P ₁ in the inflow line, and is approximately constant, which is smaller even if the pressure in the inflow line p ₁ fluctuates slightly. The pressure in the outflow line is maintained at a pressure of p ₂ .

By the way, if the ambient temperature at the location where this device is installed rises, for example, it will become △t lower than the temperature at the time of pressure setting.
Suppose that the temperature increases by ℃. In this case, the hollow cylindrical container 11 is first heated until it becomes equal to the ambient temperature, expands, and the part shown in the figure becomes △
Just stretched out. For this reason, the amount of depression δ ₁ of the spring presser 20 set using the adjustment screw 21 described above is δ ₁
−△. Further, since the hollow cylindrical container 11 is made of metal, such as aluminum, and is a good conductor of heat, the temperature of the air in the internal space 26 rises to approximately the same level as the ambient temperature. Therefore, coil spring 1
9 and the cylindrical block 18 are heated by the heated air, the temperature rises by Δt' (where Δt'≦Δt), and each is expanded by thermal expansion. Now, △
Assuming that t = 30°C, = 50 mm, and the hollow cylindrical container 11 is made of aluminum, its linear expansion coefficient d =
Since 2.313×10 ^-5 /deg, △=50×30×
2.313×10 ^-5 ≒0.035mm, while cylindrical block 18
is a polypropylene material, and its coefficient of linear expansion is
d′=11.0×10 ^-5 /deg, and △t′=25 mentioned above
℃, and its thickness h=10 mm, the elongation of this cylindrical block 18 △h=10×25×11.0×
10 ^-5 ≒0.028mm. In addition, since the coil spring 19 itself also rises in temperature and is slightly stretched, the amount of decrease Δ in the pressing down amount δ ₁ of the spring presser 20 with respect to the coil spring 19 is mainly due to the pressing force Δh of the cylindrical block 18 described above, and the This is substantially canceled by the expansion of the coil spring 19, and the effect on the set pressure _p2 due to the above-mentioned increase in ambient temperature is eliminated.

According to the results of actual measurements in a conventional device - one in which the cylindrical block 18 is removed from the configuration of the illustrated example device and the number of turns of the coil spring 19 is increased accordingly, the fluid on the outflow side decreases as the ambient temperature rises by 10°C. Although the pressure was lowered by about 1%, almost no change was observed in this device, and the temperature compensation effect was evident.

From this, the thickness h of the cylindrical block 18 is set to the length of the internal space 26 of the hollow cylindrical container 11 so that the relationship h=xd/d' is established, in other words, the lower part of the coil spring 19 The cylindrical block 18 to be inserted into the container is made of a plastic material (for example, polypropylene) whose coefficient of linear thermal expansion is much larger than that of metal, and its thickness h is determined by the length of the internal space of the hollow cylindrical container 11. It can be seen that it is sufficient to multiply d/d' by the inverse ratio d/d' of their linear expansion coefficient values.

As is clear from the above explanation, in the pressure regulating valve according to this invention, a plastic material is used between the coil spring of the adjustment mechanism that adjusts the opening degree of the throttle valve section connected to the inflow pipe and the movable valve body. A cylindrical block consisting of is interposed, and the thickness of this block is
Since the adjustment mechanism is designed to maintain an inverse ratio of the linear expansion coefficient values of the respective constituent materials of the block and the container to the length of the internal space of the container in which the adjustment mechanism is built, the outflow pipe After the pressure of the coil spring is set, a change in the set compression amount of the coil spring caused by a change in the ambient temperature at the location where the pressure regulating valve is installed is mainly canceled by a dimensional change in the thickness of the block that occurs almost simultaneously; It is possible to eliminate the influence of the above-mentioned change in ambient temperature on the set pressure, and it also has a temperature compensation function.

[Brief explanation of the drawing]

The figure is a side sectional view of an embodiment of the device according to this invention. 11...Hollow cylindrical container, 12...Cylindrical base, 1
5... Throttle valve part, 15'... Movable valve body (ball), 16
... Bellows, 17 ... Cylindrical recess, 18 ... Cylindrical block, 21 ... Adjustment screw, 22 ... Transmission rod, 1
6, 17, 18, 22...adjustment mechanism,...length of internal space of hollow cylindrical container, h...thickness of cylindrical block.

Claims (1)

[Scope of utility model registration request] The adjustment mechanism that adjusts the pressure in the outflow pipe has a coil spring, and the movable valve body of the throttle valve connected to the inflow pipe is moved via the coil spring to adjust the opening degree of the valve. In a direct acting pressure regulating valve that adjusts the pressure of the outflow pipe by adjusting the pressure in the outflow pipe, a cylindrical block made of plastic material is interposed between the coil spring and the movable valve body, and the thickness of this block is The pressure regulating valve is characterized in that the length of the internal space of the container in which the adjusting mechanism is built is set in an inverse ratio of the linear expansion coefficient values of the respective constituent materials of the block and the container.