JPH0451271Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a relief valve used in a blower relief valve or the like.

(Prior art) For example, the fourth relief valve used in a blower, etc.
There is a relief valve as shown in the figure. This valve body 1 is seated on a valve seat 4 fixed to a valve house 2, and the valve body 1 is biased in the closing direction by a relief spring 6 via a valve stem 5. The discharge pressure of the blower acts on the seated valve body 1 from below in the figure, and the opposite side of the valve body 1 is open to the atmosphere. Then, when the discharge pressure acting on the valve body 1 exceeds the repulsive force of the relief spring 6, the valve body 1 is pushed up, and air is discharged into the atmosphere through the gap formed between the valve body 1 and the valve seat 4.

Incidentally, such a relief valve generally has operating characteristics as shown in FIG. In other words, when the pressure acting on the valve body 1 rises to a set value (blow start pressure), the valve body 1 is pushed open and air starts blowing, and when the pressure increases to a constant pressure (blowout pressure) while pushing the valve body 1 further up. When a stable discharge state is reached and the pressure rises on the upstream side is removed and the pressure decreases, the valve body 1 is again displaced to the closing side, and when the pressure decreases to a certain value (stop pressure), the valve body 1 moves to the valve seat 4. to stop air evacuation.

On the other hand, depending on the application, it may be necessary to modify these basic characteristics; for example, when used as a safety valve, it is considered desirable to bring the blowing pressure close to the blowing start pressure. Therefore, in this relief valve, in addition to setting the spring load of the relief spring 6 using the adjustment bolt 8, the adjustment ring 11 screwed on the outside of the valve seat 4 is rotated to push up the valve body 1, thereby increasing the discharge pressure. By changing the pressure receiving area and the radius of the opening, it is possible to change the settings of the operating characteristics including the blowout pressure.

(Problem to be solved by the invention) However, in this case, changing the operating characteristics using the adjustment ring 11 changes the blowing start pressure as well as the blowing pressure, and the blowing pressure is changed without affecting the blowing starting pressure. Therefore, for example, it is impossible to set the blowing pressure lower than the blowing start pressure, resulting in a problem that the range in which the operating characteristics can be set is narrow.

In view of the above problems, the present invention aims to provide a relief valve whose operating characteristics can be arbitrarily set over a wide range.

(Means for Solving the Problems) The present invention provides a valve body with an annular valve seat formed facing the fluid passage and a valve body that is biased by a relief spring and seats on the valve seat from the opposite side. In the assembled relief valve, a different diameter part is formed behind the seating part of the valve body and has a larger diameter than the seating part, and an adjustment ring that covers the outside of this different diameter part with an annular gap is attached to the valve body. The inner circumferential surface of the adjustment ring is formed into a tapered shape, and a discharge path for fluid that enters by displacing the seating portion is formed via this annular gap.

(Function) Create a drainage path for the fluid that enters the inside of the valve body.
Since it is configured via an annular gap between the different diameter part formed behind the seating part of the valve body and the adjustment ring that covers the outside, the blowout pressure can be set without affecting the start pressure due to the area of this annular gap. be done.
Further, since the adjustment ring whose inner peripheral surface is tapered can greatly change the area of the annular gap with a slight displacement in the axial direction, the blowout pressure can be set over a wide range by selecting the mounting position of the adjustment ring.

(Example) Embodiments of the present invention are shown in FIGS. 1 to 3.

Figure 1 shows an air relief valve installed on the discharge side of a blower, in which a valve body 1 formed in the shape of a cylinder with a bottom can freely slide in the axial direction by a guide 3 fixed in a valve body 2. A seat portion 1A corresponding to the cylinder bottom abuts an annular valve seat 4 formed at the lower end of the valve body 2 from the inside. The outside of the valve seat 4 faces the discharge passage of a blower (not shown), and the valve body 1 receives the action of this discharge pressure from below in the figure via the seat 1A, while the valve stem 5 that abuts the back surface of the seat 1A is biased in the closing direction by the relief spring 6 via. The relief spring 6 is housed inside the valve body 1 and is held between the upper and lower spring receivers 7A and 7B. The lower spring receiver 7B abuts the large diameter tip of the valve stem 5 from behind, and the upper spring receiver 7A is supported by the tip of an adjustment bolt 8 disposed outside the valve stem 5. The adjustment bolt 8 is screwed into the valve body 2, and the spring receiver 7A is displaced in the axial direction by rotating the eastern portion of the valve body 2 that projects outward.

Behind the seating portion 1A of the valve body 1, a large diameter portion 9 of a different diameter is formed which projects laterally in the shape of a brim. Also,
A cylindrical guide 1 installed at the bottom of the valve body 2
An adjustment ring 11 screwed into the outer surface of the different diameter portion 9 covers the outer side of the different diameter portion 9. The inner circumferential surface 11A of the adjusting ring 11 is tapered upward and forms an annular gap 13 with a width corresponding to the axial position between the adjusting ring 11 and the different diameter portion 9. A discharge path is formed via this annular gap 13 for discharging the air that has entered the valve body 2 by pushing aside the seating portion 1A into the atmosphere. Note that 12 is a fixing bolt for fixing the rotational position of the adjustment ring 8.

Next, the action will be explained.

When the valve body 1 of this relief valve is pushed open by the discharge pressure, air enters the inside of the valve body 2 and enters the atmosphere through the annular gap 13 formed between the different diameter portion 9 and the adjustment ring 11. released.

In this process, the set pressure (starting pressure) _P1 at which the valve body 1 starts to open is expressed by the following equation.

P ₁ ≒κχ/(πD ₁ ² /4) ...(1) where κ: Spring constant χ: Deflection amount of spring when valve is closed D ₁ : Inner diameter of valve seat In addition, the annular gap 13 is sufficiently wide. The blowout pressure P ₂ when the flow rate after opening the valve is defined by the gap between the seating portion 1A and the valve seat 4 is expressed by the following equation.

P ₂ ≒κ (χ + Δχ ₁ ) / (πD ₁ ² /4) = P ₁ + κΔχ ₁ / (πD ₁ ² /4) = P ₁ + ΔP ₁ ...(2) However, Δχ ₁ : Lift amount of the valve body On the other hand , the blowing pressure when the annular gap 13 is narrow and the flow rate after opening is defined by this annular gap 13
P ₃ is expressed by the following formula.

P ₃ ≒κ (χ + Δχ ₂ ) / (πD ₂ ² /4) ...(3) However, Δχ ₂ : Lift amount of the valve body D ₂ : Diameter of the different diameter part From the above equations (1) and (2) P ₁ < P ₂ and furthermore, the formula
If (χ+Δχ ₂ )/χ<D ₂ ² /D ₁ ² (4) holds from (1) and (3), then P ₃ <P ₁ <P ₂ .

In other words, when the annular gap 13 is sufficiently wide, that is, when the adjustment ring 11 is located toward the bottom in the figure, the blowout pressure is P ₂ , and on the other hand, when the adjustment ring 8 is located toward the top, the blowout pressure is expressed by equation (4). As long as the following conditions are satisfied, the blowing pressure will be P ₃ . Equation (4) is determined by the position of the adjustment bolt 8 that adjusts the deflection of the relief spring 6 and the diameter D ₂ of the different diameter portion 9. Therefore, by appropriately setting these, the operating characteristics can be arbitrarily set within the range shown in FIG. 2 depending on the area of the annular gap 13. Note that this annular gap 13
Since the inner circumferential surface 11A of the adjustment ring 11 is tapered, the area can be changed steplessly and smoothly by rotating the adjustment ring 11 screwed onto the guide 10 and displacing it in the axial direction.

In this way, it becomes possible to match the blowing start pressure and the blowing pressure, or to set the blowing pressure to be lower than the blowing starting pressure. Note that when the blowing pressure is lower than the blowing start pressure, the load applied to the upstream side in the blowing state becomes smaller, which is a preferable characteristic when used as an unload valve.

FIG. 3 shows a vacuum breaker installed on the suction side of the blower, which is the opposite of the relief valve shown in FIG. The valve body 1 is pushed down to flow into the connecting flange 14. Here, the seating portion 1A is seated on the valve seat 4 from below and is biased upward by the relief spring 6 housed in the upper valve body 2. A different diameter portion 9 is formed at the lower part of the valve body 1, that is, on the downstream side of the seating portion 1A, and an adjustment ring 11 is attached to the valve body 2 so as to cover the outside thereof. The inner peripheral surface 11A of the adjustment ring 11 tapers outward at the lower end, and its axial position is determined by the thickness of the shim 15 interposed between the connection flange 14 and the valve body 2. . In this way, when the present invention is applied to a vacuum breaker, the operating characteristics can be set in a variety of ways, similar to the relief valve.

(Effects of the invention) As described above, in the relief valve of the invention, the fluid discharge path is formed via the annular gap between the variable diameter part behind the seating part of the valve body and the adjustment ring. The blowing pressure can be set without affecting the blowing start pressure. Further, since the inner circumferential surface of the adjustment ring is tapered, the area of the annular gap varies steplessly and over a wide range depending on the axial position of the adjustment ring. Therefore, operating characteristics can be set in a variety of ways by operating the adjustment ring, improving the relief valve's ability to respond to applications and usage conditions.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a relief valve showing an embodiment of the present invention, Fig. 2 is a graph showing the operating characteristics, and Fig. 3 is a sectional view of a relief valve showing an embodiment of the present invention.
The figure is a sectional view of a vacuum breaker showing another embodiment. FIG. 4 is a sectional view of a conventional relief valve, and FIG. 5 is a graph showing general operating characteristics of the relief valve. 1...Valve body, 1A...Seating part, 2...Valve body, 4...Valve seat, 6...Relief spring,
9...Different diameter section, 11...Adjustment ring, 11A...
Inner peripheral surface, 13... annular gap.

Claims (1)

[Scope of utility model registration request] In a relief valve in which a valve body houses an annular valve seat formed facing the fluid passage and a valve body that is biased by a relief spring and seats on this valve seat from the opposite side, An adjustable ring is formed on the valve body to cover the outer side of the different diameter section through an annular gap, and the inner peripheral surface of the adjustment ring is formed into a tapered shape. A relief valve characterized in that a discharge path for fluid that enters by displacing a seating portion is configured via this annular gap.