JPS6224139Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an unloader valve.

Such a valve is provided, for example, in the middle of the cleaning liquid supply pipe SP from the pump P to the cleaning gun G, as shown by the symbol UV in FIG.
During continuous operation, whenever the cleaning gun G is closed due to work procedure and no longer consumes the supplied fluid, the supplied fluid is returned to the fluid supply source T through the return pipe RP to prevent overloading of the pump P and generation of abnormal pressure. do.

For example, as shown in FIG. 2, this unloader valve UV is configured to close the opening a of the inner end of the fluid introduction passage into the valve chamber B, which has an opening a at the bottom of the inner end of the fluid introduction passage A. Piston D biased by spring C
is fitted therein, and has a fluid discharge path E from the piston pressure receiving chamber b formed between the bottom of the valve chamber B and the piston D to the outside. The supply fluid from the pump P always reaches the fluid introduction path A, and as soon as it is no longer consumed, the pressure increases and the piston D is pushed up.
As a result, the inner end opening a of the fluid introduction path is opened, and the supplied fluid is released into the fluid discharge path E through the piston pressure receiving chamber b, and is returned to the fluid supply source T through the return pipe RP. At this time, the piston D receives the fluid pressure of the discharged fluid passing through the piston pressure receiving chamber b over the entire pressure receiving surface d. is kept open by increasing the Gun G
When the piston opens and begins to consume the supply fluid, the pressure of the supply fluid decreases significantly, and the piston D cannot be held in the open position against the spring C, and the piston D is closed by the bias of the spring C. , preventing escape of supply fluid and ensuring fluid supply at a predetermined flow rate and pressure.

However, the conventional valve, as shown in Figure 2,
The fluid discharge path E is simply communicated with the piston pressure receiving chamber b at one location on one side thereof. Therefore, the fluid entering the piston pressure receiving chamber b from the fluid introduction path A is moved from the inflow position to the fluid discharge path E on one side.
It immediately flows away via the shortest straight path to.
Therefore, the working pressure of the discharged fluid against the pressure receiving surface d of the piston D is reduced by the fluid discharge path E of the piston pressure receiving chamber b.
A large difference occurs at the opening and on the opposite side, tending to tilt the piston D. In addition, turbulence is likely to occur due to uneven local flow in a large room.
This also causes the piston D to vibrate.

These inclinations and vibrations of the piston D greatly affect the operating characteristics and durability of the valve, so the dimension in which the piston D is guided by the valve chamber B is increased, and not only the piston D but also the valve chamber B becomes large, and the valve The whole thing is large and relatively heavy. Furthermore, despite such measures, the vertical vibration of the piston D cannot be sufficiently prevented. Furthermore, the fact that the fluid flowing into the piston pressure receiving chamber b immediately flows out to the fluid discharge path E through the locally shortest path within the pressure receiving chamber b is as follows.
The total filling pressure in the piston pressure receiving chamber b itself is the pump P.
Reduce the normal fluid supply pressure by For this reason, the valve return characteristic, that is, the pressure receiving surface of the piston D when it is open is larger than the pressure receiving surface when the fluid introduction passage inner end opening a is closed, and once it is opened, considerable pressure due to normal consumption of the supplied fluid is generated. The characteristic that it will not close unless there is a decrease in the temperature decreases.

In an attempt to solve this problem, even if the area magnification of the pressure receiving surface when the piston D is closed and the pressure receiving surface when the piston D is open is increased, the piston pressure receiving chamber b will increase by that amount, causing the pressure drop and the uneven pressure against the piston D. This leads to an increased tendency of action, further increasing the deterioration of the valve return characteristic. Further, although a pressure regulating constriction section F is normally provided in the fluid discharge path E, the set pressure of this section cannot be much higher than the normal fluid supply pressure by the pump P in order to prevent the pump P from being overloaded. For this reason, the piston pressure receiving chamber b
It is not possible to significantly restrict the fluid that has entered the valve from immediately flowing out to the fluid discharge passage through the shortest route, and the deterioration of the valve return characteristic is hardly eliminated.

Deterioration of valve return characteristics is especially important for reciprocating pumps P.
When the fluid is pulsating in the fluid supply system, the valve may return to its original state at the lowest pressure of the pulsation, causing malfunction.

The object of this invention is to provide an unloader valve that can solve the above-mentioned conventional drawbacks by improving the fluid outflow structure from the piston pressure receiving chamber to the fluid discharge path.

In this invention, a piston biased by a spring is inserted into a valve chamber whose inner end of the fluid introduction passage is open at the bottom, and is biased by a spring to keep the inner end opening of the fluid introduction passage open at all times.
In a relief valve that has a fluid discharge path to the outside from a piston pressure chamber formed between the bottom of the valve chamber and the piston, the fluid discharge path is arranged equidistantly around the axis of the piston pressure receiving surface with respect to the piston pressure receiving chamber. The gist of achieving the above object is to communicate through a plurality of communication holes that open at certain positions.

Referring to the embodiment shown in FIGS. 3 to 5, the valve body 1 has a downward fluid inlet passage 2, a sideways fluid discharge passage 3, and an upwardly extending inner end of the fluid inlet passage 2 at the bottom 4a. It has a valve chamber 4 with an opening 2a. A piston 5 that opens and closes the inner end opening 2a of the fluid introduction path at the bottom of the valve chamber 4 by vertical movement.
is inserted from above and is biased downward by a spring 6 to constantly close the opening 2a. The piston 5 is guided in airtight contact with the inner periphery of the valve chamber 4 by an O-ring 8 attached to its outer periphery groove together with a back-up spring 7. A spring housing cylinder 9 is screwed 10 to the upper end opening of the valve chamber 4, a pressure regulating screw cap 12 is screwed 11 to the upper end of the cylinder 9, and one end of a spring shaft 14 is fitted 13 into the center of the back surface of the piston 5. The other end of the spring shaft 14 is loosely fitted into a pocket 12a on the inner surface of the pressure regulating screw cap 12.

The fluid introduction path inner end opening 2a is located at the bottom 4a of the valve chamber 4.
The fluid introduction passage cap 16 is removably attached by screwing 15 to the valve body 1, and the cap 16 is connected to the fluid introduction passage 2 of the valve box 1 and partitions the fluid introduction passage 2 and the fluid discharge passage 3. The valve chamber bottom portion 4 is provided in the cylindrical portion 16a.
A flange 16b is integrally formed, which forms a part or the entirety of a and partitions the piston pressure receiving chamber 4b between the piston 5 and the valve chamber bottom 4a and the fluid discharge path 3. On the flange 16b of this cap 16,
Three communication holes 17 are formed to open and communicate the fluid discharge path 3 with the piston pressure receiving chamber 4b at equidistant positions around the axis of the pressure receiving surface 5a of the piston 5. The fluid discharge passage 3 communicates with each of the communication holes 17 at an annular passage 18 section below the flange 16b, and is connected to the piston pressure receiving chamber 4.
Leads to b.

Inside the external connection port 3a of the fluid discharge path 3, a pressure regulating aperture ring 21 and an O-ring 22 are installed, which are held by a connecting fitting 20 or the like that is screwed 19 therein. Cylindrical portion 16a of cap 16 and valve box 1
An O-ring 23 is also interposed at the connection portion with the fluid introduction path 2 . Reference numeral 2b indicates an external connection port of the fluid introduction path 2, and reference numeral 27 indicates a stopper ring clamped between the connection portion between the valve chamber 4 and the spring housing cylinder 9, which restricts the upward movement position of the piston 5.

A valve seat 24 with a counterbore is formed in the inner end opening 2a of the fluid introduction path, and a valve seat 25 facing the valve seat 24 is loosely fitted 26 in the center of the pressure receiving surface 5a of the piston 5. As the valve seat 25 moves up and down, it moves toward and away from the valve seat 24 to open and close the opening 2a. The valve seat 25 is loosely fitted into the piston 5, but when the opening 2a is closed, it is in pressure contact with the valve seat 24, and when the opening 2a is open, the piston 5 receives fluid pressure.
Since it is crimped to the piston 5, it will not fall off from the piston 5 during use, and is convenient for attachment and detachment during assembly and repair. The axes of the piston pressure receiving surface 5a and the opening 2a are aligned.

In the case of the above structure, the fluid introduced from the pump or the like reaches the fluid introduction path 2, and when the pressure of the supplied fluid increases due to interruption of consumption of the supplied fluid, the fluid is introduced to the piston 5 through the pressure receiving surface 5a. In order for the fluid pressing force acting on the area of the inner end opening 2a to overcome the biasing force of the spring 6, the supplied fluid pushes up the piston 5 against the spring 6, opens the opening 2a, and flows into the piston pressure receiving chamber 4b. do. The supply fluid that has flowed into the chamber 4b acts on the entire range of the pressure receiving surface 5a of the piston 5, increasing the pressing force on the piston 5, and while holding the piston 5 in the upward movement position, the three communication holes 17 through which it flows out into the annular passage 18 and into the fluid discharge passage 3.

Each communication hole 17 regulates the outflow direction and position of the supply fluid that has flowed into the piston pressure receiving chamber 4b, and the supply fluid that flows into the pressure receiving chamber 4b through the opening 2a is directed from the opening 2a toward each communication hole 17. After spreading evenly radially into the piston pressure receiving chamber 4b, it flows out through each communication hole 17.
For this reason, the ability of the outflowing supply fluid to fill and stay in the piston pressure receiving chamber 4b is increased compared to the conventional case, and the piston 5 can be easily maintained in the upward position, so that the pulsating supply fluid by the reciprocating pump is increased. Even at pulsating low pressure, it is stabilized in the upward position and does not cause malfunction. Furthermore, if each communication hole 17 is given a pressure regulating throttling action that adjusts the supply fluid discharge pressure by setting the total passage cross-sectional area and passage length of each communication hole 17, the above-mentioned filling property and retention property are further improved. do. In this case, the pressure regulating orifice ring 21 can be omitted, and even if it is employed, it is convenient to use it for fine adjustment.
Further, if the valve seat 24 becomes worn out or if it is desired to change the conditions set by the communication hole 17, the cap 16 can be replaced.

Further, the supply fluid that spreads evenly radially from the opening 2 into the piston pressure receiving chamber 4b and flows out from each communication hole 17 does not exert any uneven pressure on the pressure receiving surface 5a of the piston 5, and the flow is in a laminar flow state. It is quiet and does not tilt or vibrate the piston 5.

The communication holes 17 only need to be equally spaced around the axis of the piston pressure-receiving surface 5a, and may be provided on the inner periphery of the piston pressure-receiving chamber 4b, and their shape and number are arbitrary.

In this device, a piston is fitted into a valve chamber whose inner end of the fluid introduction channel is open at the center of the bottom, and when the piston is slid inside the valve chamber toward the bottom wall, the inner end opening of the fluid introduction channel can be closed. The unloader valve is an unloader valve in which the piston is always biased in the direction of closing the inner end opening of the fluid introduction passage, and the communication passage communicating with the fluid discharge passage is arranged around the inner end of the fluid introduction passage. Since there are multiple openings at equal positions in the circumferential direction, a pressing force is applied to the piston through the inner end opening of the fluid introduction passage, and the piston is pushed up while resisting the biasing force to open the inner opening of the fluid introduction passage. The supply fluid flowing into the piston pressure receiving chamber attempts to flow out to the fluid discharge passage through each communication hole, spreads evenly around the piston pressure receiving chamber, and flows out while filling the piston pressure receiving chamber, causing the fluid to flow out from the piston pressure receiving chamber. The ability of the outflowing fluid to fill and stay in the piston pressure receiving chamber increases, improving the return characteristics of the valve.

In addition, the flow of fluid that enters the piston pressure receiving chamber, expands and fills it, and then flows out is quiet, close to laminar flow, and does not create uneven pressure, so the piston is less likely to tilt or vibrate, and the valve is less likely to tilt or vibrate. The operating characteristics of the system are improved. In addition, the piston can be guided within a small range, resulting in a smaller size and lighter weight overall.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the use of the unloader valve, Fig. 2 is a partial sectional view of a conventional valve, Fig. 3 is a side view of an embodiment of the invention, with half of the valve cut away, and Fig. 4. is a partial slope view, and Fig. 5 is a cross-sectional bottom view. 2...Fluid introduction path, 2a...Inner end opening, 3...
Fluid discharge path, 4...valve chamber, 4a...bottom, 4b...
... Piston pressure receiving chamber, 5 ... Piston, 5a ... Pressure receiving surface, 6 ... Spring, 16 ... Fluid introduction channel cap, 1
6a...Cylinder part, 16b...Flange, 17...Communication hole, 21...Pressure adjustment aperture ring.

Claims (1)

[Claims for Utility Model Registration] (1) A piston is fitted into a valve chamber whose inner end of a fluid introduction passage is open at the center of the bottom, and when the piston is slid inside the valve chamber toward the bottom wall, fluid is introduced. The inner end opening of the fluid introduction channel can be closed, the piston is always biased in the direction of closing the inner end opening of the fluid introduction channel, and a plurality of communication holes are opened at equal circumferential locations around the inner end of the fluid introduction channel, An unloader valve characterized in that a communication hole communicates with a fluid discharge path. (2) The unloader valve according to claim 1 of the utility model registration claim, wherein the communication hole also serves as a pressure regulating orifice hole. (3) The unloader valve according to claim 1 or 2, wherein the fluid discharge passage is provided with a pressure regulating orifice. (4) The unloader valve according to claim 1 or 2, wherein the communication hole is formed around the inner end opening of the fluid introduction path at the bottom of the valve chamber. (5) The communication hole is provided in the flange part that partitions the piston pressure receiving chamber side and the fluid discharge path side of the mouthpiece on the inner end of the fluid introduction path, which is removably attached to the bottom of the valve chamber. The unloader valve according to item 4.