JP2977921B2 - Decompression orifice - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decompression orifice capable of reducing the pressure of a fluid without difficulty to maintain a constant flow rate of the fluid.

[0002]

2. Description of the Related Art Conventionally, as one form of a decompression orifice,
There is one shown in FIG.

The pressure reducing orifice a is formed in an annular disk with elastic rubber and provided with a through hole b.
The pressure of the fluid d passing through is reduced to achieve a constant flow rate.

That is, as shown in FIG. 9, while the fluid d passes through the passage hole b, the pressure is not reduced, the flow velocity of the fluid d increases, and the inflow pressure (temporary pressure) into the passage hole b is temporarily increased. When the pressure rises, the pressure reducing orifice a deforms as shown in FIG. 10 to reduce the diameter of the passage hole b, thereby preventing an increase in the secondary pressure and functioning to achieve a constant flow rate.

[0005]

However, in the case of the above-mentioned pressure reducing orifice a, the fluid is forced to be deformed as a whole around the passage hole b, and since the material is made of elastic rubber, the flow of the fluid is reduced. As a result, the constant flow rate function described above cannot be performed, and replacement must be performed frequently.

[0006]

Accordingly, in the present invention, a pressure receiving groove is formed along the periphery of the fluid passage hole on the fluid inflow side end face of the orifice body formed of an elastic material and having a fluid passage hole at the center. It is another object of the present invention to provide a decompression orifice in which a ring-shaped throttle portion is formed between the pressure receiving groove and the fluid passage hole.

[0007] The present invention is also characterized by the following configuration.

[0008] It is formed of an elastic resin.

The use of a thermoplastic polyester elastomer as the elastic resin.

[0010] The water discharge nozzle can be assembled into a spear.

[0011]

When the pressure reducing orifice according to the present invention is used, the pressure reducing orifice is disposed in the fluid flow path such that the pressure receiving groove is positioned on the fluid inflow side, and the fluid flows through the fluid passage hole. Let it pass.

At this time, when the primary pressure which is the inflow pressure of the fluid rises, the pressure of the fluid acting in the pressure receiving groove rises,
Due to the pressure of the fluid acting in the pressure receiving groove, only the throttle portion is bent toward the fluid passage hole side, the diameter of the inflow side of the fluid passage hole is reduced, the fluid is depressurized without difficulty, and the secondary pressure rises To prevent

As a result, the pressure of the fluid does not increase above the set pressure, and the flow rate does not increase above a certain flow rate.

[0014] The reduced-pressure orifice is made of an elastic resin, particularly a thermoplastic polyester elastomer having excellent elastic recovery, low creep, high load resistance, and abrasion resistance. Can be prevented.

Further, the above-mentioned pressure reducing orifice can be incorporated in a water discharge nozzle pipe spear, for example, to spray water at a constant water discharge pressure and a constant water discharge amount by the nozzle pipe spear to efficiently extinguish fire extinguishing activities and the like. Can do it.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

A shown in FIG. 1 is a decompression orifice according to the present invention.

The pressure reducing orifice A is formed of an elastic material, and a pressure receiving groove 3 is formed along the peripheral edge of the fluid passage hole 2 on the fluid inflow side end surface 1a of the orifice body 1 having a fluid passage hole 2 at the center. A ring-shaped throttle 4 is formed between the pressure receiving groove 3 and the fluid passage hole 2. 1b is an end face on the fluid outflow side.

The reduced pressure orifice A is made of an elastic resin,
In particular, it is preferable to mold with a thermoplastic polyester elastomer. According to such a material, it exhibits rubber elasticity without losing flexibility even in a low temperature range, has little permanent set due to tension or compression, and has excellent recovery from deformation. It has excellent bending fatigue resistance and tear propagation resistance, and can maintain its toughness without being damaged by many oils, solvents and ozone.

FIG. 2 is an explanatory view of the operation principle of the pressure reducing orifice A when the above described pressure reducing orifice A is disposed in the flow path 5.

That is, the pressure reducing orifice A is disposed so that the pressure receiving groove 3 is located on the inflow side, and the fluid is passed through the fluid passage hole 2.
The primary pressure, which is the inflow pressure of the fluid, rises, and the throttle portion 4 is bent toward the fluid passage hole 2 by the pressure of the fluid acting in the pressure receiving groove 3, so that the fluid passage hole The diameter D1 of the inflow side 2 is reduced in the shape of a throttle to become the diameter D2 of the inflow side, and the fluid is naturally reduced in pressure to prevent an increase in the secondary pressure.

FIG. 3 is a graph showing the relationship between the primary pressure and the secondary pressure obtained from the experimental results. Before the throttle portion 4 is reduced in diameter to the inlet side diameter D2, the secondary pressure is reduced to the primary pressure. It can be seen that the secondary pressure does not increase beyond the constant (set) pressure p after that, despite the primary pressure increasing.

Therefore, the flow rate does not increase beyond a certain flow rate. Q is a relation curve between the primary pressure and the secondary pressure, and R is an imaginary line proportional to the primary pressure and the secondary pressure.

Next, a water discharge nozzle pipe spear B incorporating the pressure reducing orifice A constructed as described above will be described with reference to FIGS.

That is, the water discharge nozzle pipe spear B is connected to the conduit 11
A pipe spear fitting 12 is attached to the base end of the pipe, a hose connecting fitting 13 and a handle 14 are attached to the pipe spear fitting 12, and a pipe spear tip fitting 15 is attached to the tip of the conduit 11, and the pipe spear tip is attached. The nozzle 16 is attached to the metal fitting 15.

A pressure reducing orifice A is incorporated in the pipe spear metal fitting 12, and a retainer 18 having a finger hook pin 18a is arranged upstream of the pressure reducing orifice A.
The plate 17 is arranged on the downstream side.

A rectifying body 19 is disposed in the conduit 11, and the rectifying body 19 has a cylindrical surface formed to have substantially the same diameter as the inner diameter of the conduit 11, as shown in FIG. It is bent in an arc inward at six places to form an arc-shaped outer peripheral surface 19a, and the arc-shaped outer peripheral surface 19a is formed.
An outer rectification forming path 20 can be formed between a and the inner peripheral surface of the conduit 11, and an inner rectification forming path 21 is formed in the rectifier 19.

The water flow decompressed by the decompression orifice A is allowed to flow through the outer shaping flow path 20 and the inner shaping flow path 21 to rectify the water flow.
The flight distance of the released water can be secured more than a certain level.

In FIG. 1, reference numerals 22 and 23 denote O-rings, and reference numeral 24 denotes a conduit 11.
A grip attached to the outer peripheral surface of 25, a shoulder band, 26
Is a band stopper.

6 to 8 are explanatory diagrams of the operation of the pressure reducing orifice A incorporated in the water discharge nozzle pipe spear B.

FIG. 6 shows a water flow W flowing from a water source through a hose connected to a hose connection fitting 13.
Shows a state in which the flow is contracted by the decompression orifice A.

FIG. 7 shows a case where the primary pressure of the water flowing into the fluid passage hole 2 of the decompression orifice A is increased. The water pressure acting on the pressure receiving groove 3 causes the throttle portion 4 to move the fluid passage hole 2. It is slightly bent to the side.

FIG. 8 shows a state in which the throttle portion 4 is bent to the maximum and the secondary pressure is kept at the set pressure p.

At this time, the fluid inlet side end face 1a of the pressure reducing orifice A is pressed against the retainer 18 and the fluid outlet side end face 1b
Is pressed against the plate 17 so as to maintain the inflow side diameter D2 of the narrowed portion 4 in the reduced diameter state.

[0035]

According to the present invention, the following effects can be obtained.

A throttle portion is formed in the pressure reducing orifice, and the throttle portion bends in response to the rising primary pressure to prevent a rise in the secondary pressure. The flow rate can be kept below a certain flow rate.

The pressure reducing orifice is made of an elastic resin, particularly a thermoplastic polyester elastomer having excellent elastic recovery, low creep, high load resistance and abrasion resistance. To extend the life of the decompression orifice and extend the replacement period.
The complexity of maintenance and the like can be eliminated.

By incorporating a pressure reducing orifice into, for example, a water discharge nozzle pipe spear, the water discharge pressure and water discharge amount of the nozzle pipe spear can be made constant, and the efficiency of fire extinguishing activities and the like can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a decompression orifice according to the present invention.

FIG. 2 is an explanatory view of the operation principle of the pressure reducing orifice.

FIG. 3 is a graph showing a relationship between a primary pressure and a secondary pressure of a fluid when the pressure reducing orifice is used.

FIG. 4 is a partially cutaway side view of a water discharge nozzle pipe spear incorporating the decompression orifice.

FIG. 5 is a perspective view of a rectifier incorporated into the water discharge nozzle pipe spear.

FIG. 6 is an explanatory view of the operation of the pressure reducing orifice.

FIG. 7 is an explanatory diagram of the operation of the pressure reducing orifice.

FIG. 8 is an explanatory diagram of the operation of the pressure reducing orifice.

FIG. 9 is an explanatory sectional view of a conventional decompression orifice.

FIG. 10 is an explanatory view of a reduced pressure state of the reduced pressure orifice.

[Explanation of symbols]

 A pressure reducing orifice 1 orifice body 2 fluid passage hole 3 pressure receiving groove 4 throttle section

Claims (4)

(57) [Claims] 1. An orifice body 1 formed of an elastic material and having a fluid passage hole 2 at a center portion thereof has a fluid inflow side end face 1a.
A pressure reducing orifice characterized in that the pressure receiving groove 3 is formed along the periphery of the fluid passage hole 2 and a ring-shaped throttle 4 is formed between the pressure receiving groove 3 and the fluid passage hole 2. 2. The decompression orifice according to claim 1, wherein the orifice is formed of an elastic resin. 3. The reduced pressure orifice according to claim 2, wherein a thermoplastic polyester elastomer is used as the elastic resin. 4. The pressure reducing orifice according to claim 1, wherein the orifice can be incorporated into the water discharge nozzle pipe spear B.