WO1998030859A1

WO1998030859A1 - Gas pressure regulator for a paintball gun having additional overpressure vent valve

Info

Publication number: WO1998030859A1
Application number: PCT/AU1997/000834
Authority: WO
Inventors: Warwick Charles Mcmullen
Original assignee: Warwick Charles Mcmullen
Priority date: 1996-12-24
Filing date: 1997-12-08
Publication date: 1998-07-16
Also published as: AU7646796A

Abstract

A pressure regulator for dispensing gas from a high pressure supply at a predetermined reduced pressure. The regulator comprises a housing (1A, 1B) having an outlet (5) for said reduced pressure, an inlet (4) for connection to the high pressure supply and a valve (7) and valve seat (8). Springs (6, 13) apply forces to the valve (7) so that in use the valve (7) is balanced at an equilibrium position to pass gas at the predetermined reduced pressure to said outlet (5). A venting orifice (16) downstream of the valve (7) dissipates excessive outlet pressure above the predetermined reduced pressure. The operation of the venting orifice (16) is dependent upon the position of a piston (10). Orifice (21) in housing (1B) is used to recharge the high pressure supply and may include a one way valve. Main valve seat may be made of Polytrichlorofluoroethylene (Kel-f).

Description

_{GAS PR}E_SSURE RE_GULATOR FOR A PAINTBALL GUN HAVING ADDITIONAL OVERPRESSURE VENT VALVE

This invention relates to fluid regulator apparatus. More particularly although not exclusively it discloses an improved regulator for dispensing gas from a high pressure supply.

Pressure regulators are typically installed on high pressure tanks or bottles so as to dispense gas at a constant usable pressure. Existing regulators normally comprise a valve and seat assembly which is balanced by opposed spring forces and the supply pressure from the tank or bottle. By varying the spring force applied to one side of the valve the supply pressure from the regulator can be reduced to a usable value. With prior art regulators however the outlet pressure can increase up to 10% over the initial setting as the bottle or tank pressure decays with use. This is caused by the initial balance of forces on the valve being disrupted and the valve thereby moving further off the seat. In some applications such as for example skirmish paintball apparatus this increase in pressure can disqualify a player through excessive projectile velocity.

It is an object of this invention to ameliorate the aforementioned disadvantage and accordingly there is disclosed a regulator for dispensing gas from a high pressure supply at a predetermined reduced pressure, said regulator comprising a housing having an outlet for said reduced pressure, an inlet for connection to said high pressure supply and a valve and seat assembly disposed therebetween, spring means for applying forces to said valve whereby in use when the inlet is connected to said high pressure supply said valve is balanced at an equilibrium position to pass gas at said predetermined reduced pressure to said outlet and venting means downstream of said valve to dissipate excessive outlet pressure above said predetermined reduced pressure arising from movement of said valve away from said equilibrium position .

Preferably said spring means includes a coil spring acting through a piston onto the downstream side of said valve.

It is further preferred that the force applied by said coil spring may be varied by an adjustable cap in said housing.

It is still further preferred that said venting means comprises an orifice extending through the wall of said housing which dissipates said excess outlet pressure to atmosphere .

It is still further preferred that the operation of said venting means be dependent upon the position of said piston . The currently preferred form of this invention will now be described with reference to the attached representations in which :

Figure 1 is a perspective view of a gas regulator according to this concept. Figure 2 is a cross-sectional view of the regulator along the lines A-A of figure 1, Figures 3A and 3B are detailed views of the valve and valve seat which are used in the regulator of figure 1, Figure 4 is a schematic view of the preferred contact surfaces of the valve and valve seat as formed on initial assembly of the housing, and Figure 5 is a schematic view of the valve seat and valve in the equilibrium position.

Referring first to figures 1 and 2 the regulator may comprise a cylindrical housing of two pieces 1A and IB. These upper and lower sections engage via screw threads 2 An 0 ring 3 is also provided in the joint 3A for a gas tight seal. There is a threaded inlet 4 at the bottom of the housing for connection to a high pressure gas bottle or the like (not shown) and an outlet 5 in the side. During operation of the regulator the gas flows through the inlet 4, around the coil spring 6, up between the valve 7 and valve seat 8 and into a low pressure chamber 9 immediately below piston 10. From this chamber it passes through channels 11 and 12 formed between housing sections 1A and IB to a further annular chamber 12A and then outlet 5. The * position of the valve 7 in relation to the seat 8 determines the amount of gas passing through the regulator and the magnitude of the pressure at the outlet 5. This position is determined by a balance of the opposing forces applied by an upper coil spring 13 acting through the piston 10 on the downstream side of the valve and the lower coil spring 6 and inlet gas pressure on the upstream side. As best shown in figures 2 and 3A the valve preferably comprises a central cone shaped contact surface 7 . Extending out from the large end of the cone is a circular boss 7B which seats within the coil spring 6 as shown in figure 2. The opposite end of the valve is formed into a shaft 7C of reduced diameter which extends up through the valve seat 8 and flow channel 14 in the upper housing and abuts the underside of the piston 10. The valve seat 8 as also shown in figures 2 and 3B is circular with a bottom detent 8A of depth .305 mm +0.00 -.005, sealing surfaces 8B and 8C which engage against the upper and lower housing sections and a central bore 8D to receive the aforementioned valve 7. The seat is preferably made of Polytrichlorf luoroethylene (Kel-f). Detailed schematic representations of part of the contacting surfaces of the valve and valve seat are shown in figures 4 and 5. The contacting edge of the seat is preferably initially machined to a radius of .127 mm +0.00 -0.005. The contacting cone shaped surface 7A of the valve is machined to an angle A of about 45 degrees to its longitudinal axis as shown. The valve 7 is also preferably formed from stainless steel. To obtain upon initial assembly of the housing the necessary permanent deformation of the valve seat for a flat sealing area B as shown in figure 4 suitable spring constants are chosen of for the lower spring 6 and the upper spring 13.

Preferably surface finishes of 32 microinches +_5 microinches are machined onto the contacting surface of the seat and 16 microinches +_5 microinches onto the valve surface 7A for efficient sealing.

The force exerted by the upper spring 13 is adjustable by means of a threaded cap 15. Turning this cap down compresses the spring 13 and increases the force applied through the piston 10 on the downstream side of the valve. This tends to move the valve 7 further off the seat 8 and increases the gas pressure at the outlet 5. Turning the cap 15 out of the housing has the opposite effect. Typical operating pressures for a regulator of this type would be of the order of 42,000 kpa at the inlet and about 4,200 kpa at the outlet. Over time however as the high pressure gas supply is depleted the inlet pressure decreases and the previously set equilibrium position of the valve is disrupted. The result is that the valve tends to open further with an accompanying increase of up to 10% in the downstream pressure in chamber 9. In accordance with this invention however an orifice 16 is provided which extends from the piston bore 17 through to the outside of the housing and substantially reduces or eliminates this unwanted pressure. The orifice is positioned relative to the piston such that as the outlet pressure begins to rise in chamber 9 the increased force exterted on the underside of piston 10 moves it upwardly so that the piston seal 18 passes above the orifice opening. This puts the orifice in communication along piston bore 19 with chamber 9 to exhaust the increased pressure. When the pressure is reduced the piston seal 18 subsequently moves down under the action of spring 13 to the equilibrium position at which the orifice is again isolated. In operation of the regulator the piston will tend to oscillate between upper and lower positions as necessary to restrict variations in outlet pressure with this particular example to less than about 5% . With this current embodiment the diameter of the orifice is about 1.5 mm however the invention is not limited to this dimension. In addition the orifice may also act as a continuous safety vent in the event that the valve becomes jammed open or otherwise defective and passes supply pressure. The increased pressure in the chamber 9 in this case holds the piston seal 18 above the orifice 16 to continuously exhaust the excess gas. This feature is of particular value with gas powered skirmish paintball equipment as the outlet pressure for such apparatus has to be precisely limited to provide a projectile speed of no greater than 91 metres per second. Pressure variations with existing regulators make compliance with this difficult.

As a further preferred feature a lug 20 may also be formed on the top of the piston 10. This facilitates its removal for maintenance or inspection without disassembly of the valve body.

Provision for filling the supply bottle or tank is provided through an inlet 21 in the side of the housing opposite the outlet 5. Preferably the inside surface of the inlet is threaded for engagement with a non-return valve housing 22 (see figure 1). To eliminate interference between the operation of this valve and the inlet port 23 during charging of the tank the port is preferably offset to one side of the inlet as shown in figure 2. The non-return valve when open then abuts the end wall of the inlet without obstructing the port.

It will thus be appreciated that this invention at least in the form of the embodiment described provides a novel and improved form of gas regulator. Clearly however the example disclosed is only the currently preferred form of this invention and a wide variety of modifications may be made which would be apparent to a person skilled in the art. For example the shape and configuration of the housing may be changed according to application or design preference. The invention is also not limited to any particular materials for constructing the regulator although as mentioned earlier aluminium is preferred for the housing, stainless steel for the valve and springs and Kel-f for the valve seat.

For the purposes of this specification expressions such as "upper", "lower", "up", "down", "above", "below" and the like refer to the regulator in one possible position of use as shown in figures 1 and 2 and are not to be read as necessarily limiting.

Claims

The claims defining the invention are as follows:

1. A pressure regulator for dispensing gas from a high pressure supply at a predetermined reduced pressure, said regulator comprising a housing having an outlet for said reduced pressure, an inlet for connection to said high pressure supply and a valve and valve seat assembly disposed therebetween, spring means for applying forces to said valve whereby in use when said inlet is connected to said high pressure supply said valve is balanced at an equilibrium position to pass gas at said predetermined reduced pressure to said outlet and venting means downstream of said valve to dissipate excessive outlet pressure above said predetermined reduced pressure arising from movement of said valve away from said equilibrium position .

2. The regulator as claimed in claim 1 wherein said spring means includes a coil spring acting through a piston onto the downstream side of said valve.

3. The regulator as claimed in claim 2 wherein said venting means comprises an orifice in said housing which extends from the outside of said housing through to a bore for said piston to dissipate said excessive outlet pressure to atmosphere .

4. The regulator as claimed in claim 3 wherein the operation of said orifice is dependent upon the position of said piston.

5. The regulator as claimed in claim 4 wherein said piston is movable between a raised position at which said orifice is in communication with a chamber under said piston and a lower position wherein said orifice is isolated from said chamber .

6. The regulator as claimed in claim 5 wherein during operation any said excess pressure which builds up in said chamber pushes the piston to said raised position and said excess pressure is thereby dissipated to atmosphere through said orifice.

7. The regulator as claimed in claim 6 wherein said piston is fitted with a seal which at said raised postion is above said orifice and at said lower position is below said orifice .

8. The regulator as claimed in claim 7 wherein a filling inlet is provided in the housing for recharging said high pressure supply through a non-return valve, a port in said filling inlet being offset to prevent interference.

9. The regulator as claimed in claim 8 wherein the valve seat is machined from Kel-f.