Air-control System For Apparatus Displacing Material By Combustive Explosions

Abstract

An air control system for an apparatus displacing material by combustive explosions insuring that the air valve leading to the combustion chamber is closed during combustion. An air supply system for a combustive apparatus for displacing material in which the charging pressure of the air in the combustion chamber may be selected and controlled. An air control system for controlling the air inlet valve to the combustion chamber of an explosive material displacing apparatus having a relief valve with means for adjusting the pressure at which the relief valve opens with a control valve connected to and responsive to the relief valve and an air control line connected to the air supply in which the flow of air therethrough is controlled by the control valve, and a piston connected to the air inlet valve and exposed on one side to the pressure in the air control line whereby pressure passing through the control line acts on the piston in a direction to close the valve, and air bleed means connected to the air control line for relieving the air control line to allow the air inlet valve to be actuated. The air control system controlling the air supply valve to allow the full air supply pressure to be built up before charging the combustion chamber with air thereby allowing the air supply system to charge air to the combustion chamber at a higher charging rate.

Description

BACKGROUND OF THE INVENTION

Copending patent application, Ser. No. 514,057, filed Dec. 15, 1965 now U.S. Pat. No. 3,461,577 entitled Method Of And Apparatus For Displacing Materials discloses an apparatus having a combustion chamber into which a hydrocarbon fuel and air is injected and ignited to create an explosion for displacing and moving materials. It is desirable that the air inlet valve to the combustion chamber which supplies air from the charging air supply is closed when combustion is initiated or at least by the time the flame front has propagated back to the air inlet valve. Furthermore, the force of the combustive explosions from the chamber, which are desired to be varied in order to control the amount of material moved or displaced, depend upon the charging pressure of the air in the combustion chamber. The present invention provides a selective control of the initial charging pressure in the combustion chamber to provide the optimum explosive force desired for the operation conditions. The present invention is also directed to allowing the air supply system to be built up and stored to provide a higher charging rate when the air valve is open.

SUMMARY

The present invention is directed to an air control system for an apparatus having a combustion chamber which displaces material by combustive explosions by controlling the air inlet valve. The system selectively and adjustable controls the charging pressure in the combustion chamber, closes the air valve when combustion is initiated, prevents ignition of the combustion in the chamber until the air inlet valve is closed, and provides an air supply system which may be built up to capacity when the air inlet valve is closed thereby storing a supply of air to provide higher charging rates to the combustion chamber.

One feature is the provision of an air supply control system for controlling the air inlet valve between the combustion chamber and the air supply by providing a relief valve having means for adjusting the pressure at which the relief valve opens with a control valve connected to and responsive to the relief valve which in turn controls the air through an air control line and a piston connected to the air inlet valve and exposed on one side to the pressure in the air control line whereby pressure thereon acts to close the inlet valve, and air bleed means is connected to the air control line for closing the air inlet valve.

A still further feature of the present invention is the provision of an electrical switch in the combustion chamber ignition circuit positioned to be actuated by the air inlet valve when the valve is in the closed position thereby preventing firing of the combustion chamber until the inlet valve has been closed.

A further object of the present invention is the provision of means for adjusting the pressure at which the relief valve opens for selectively controlling the charging air pressure in the combustion chamber and which includes a beam one end of which engages and controls the relief valve with a spring yieldably acting against the other end of the beam, and a cam movable along the beam for providing a pivot point for varying the force of the beam on the valve whereby the position of the cam selectively controls the charging pressure in the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWING

the drawing is a fragmentary elevational view, partly in cross section, and partly schematic illustrating the air control system of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing, the reference numeral 10 generally indicates the apparatus of the present invention in use for displacing and moving material and includes an explosion cell or combustion chamber 12. The chamber 12 is charged with a suitable combustion mixture for creating an explosion therein. Preferably, the chamber is charged with an air/fuel mixture, the air being provided by any suitable and conventional means such as a compressor (not shown) through an air manifold 14 an through an air inlet valve generally indicated by the numeral 16. The fuel may be provided by any suitable and conventional fuel supply means such as a separate fuel inlet into the combustion chamber 12 such as shown in U.S. Pat. No. 3,461,577 or such as a carburetor 18 connected to the air manifold 14 to provide an air/fuel mixture at the desired mixture ratio. Combustion is initiated in the mixture in the combustion chamber 12 by any suitable ignition means such as a spark plug 20. The combustion chamber includes an outlet valve 22 for releasing the explosive pressures and gases through an outlet duct 24 for moving and displacing material. A spring 19 acts to close valve 22, and piston 21 exposed to the pressure in the combustion chamber through orifice 23. The valve 22 is kept seated during the buildup of charging pressure in the combustion chamber by the pressure acting through orifice 23 on the piston 21. However, during the rapid pressure buildup during combustion the pressure drop across the orifice will restrict the pressure rise on the piston 21 and allow valve 22 to open, all as more fully described in U.S. Pat. No. 3,461,577.

The present invention is directed to providing an air control system for controlling the actuation of the air inlet valve 16. A relief valve 26 is provided, such as a ball-type relief valve, having a ball 28 resting on a seat 30 whereby the position of the ball 28 relative to the seat 30 regulates the pressure at which air will bleed out of line 32. In order to select and control the actuation of the relief valve and thus the pressure in line 32, suitable means for adjusting the pressure at which the relief valve opens is generally indicated by the numeral 34 is provided. The adjusting means 34 includes a spring 36 which exerts a constant force, although this force can be adjusted by varying the compression of the spring through a screw adjustment 38. The spring 36 acts against one end of a floating beam 40 with the second end of the beam acting against the ball 28 of the relief valve 26. The beam 40 is generally held in position by pivotally connected floating linkages 42 and 44. A roller or cam 46 is provided between a fixed support 48 and the beam 40 and is connected to a control lever 50 which when moved in a first direction 52 acts to move the roller 46 towards the ball 28 and thus increases the force keeping the ball 28 seated on the seat 30. When the control arm 50 is moved in a second direction 54 the roller 46 is moved away from the ball 28 thereby decreasing the force seating the ball 28.

Thus the relief valve 26 will regulate the pressure at which air will bleed out of line 32. Line 32 is connected to and controls a control valve generally indicated by the reference numeral 56 which controls the flow through an air control line including lines 58 and 60. The control valve 56 may be a spool valve having a piston 62 therein having a first side 64 with a larger diameter than a second side 66 and includes an orifice 68 therethrough so that there is a constant bleeding of air across the piston 62 if a differential pressure exists across the sides 64 and 66. A valve element 70 is connected to the piston 62 and when seated on valve seat 72 closes the valve 56 and blocks communication between lines 58 and 60. In addition, if desired, a spring 74 may be provided acting upon piston 64 in a direction to close valve element 70.

If the pressure in line 32 is below the pressure selected by the actuation of the control arm 50 then the ball 28 will be seated on relief valve seat 30 allowing the pressure across piston 62 to be balanced through the orifice 68 whereby the valve element 70 is seated closing on valve seat 72 because of the greater area of side 64 of the piston 52 as compared to side 66.

The air control line 60 is connected to a chamber 76 having a piston 78 therein which is attached to the stem 80 of the air inlet valve 16. It is to be noted that the area of the side 82 of the piston 78 is larger than the area of the back side 85 of the air inlet valve 16. Therefore, when the air in chamber 76 is of equal pressure to the air in the manifold 14 the valve 16 will be closed. If desired, a spring 84' may be provided acting on the valve stem 80 to provide an additional force to keep the valve 16 closed. Bleed down means such as an orifice 84 is provided in communication with the line 60, and more rapid bleed down means are provided by an electrically actuated solenoid valve 86. Vent line 88 is provided in the chamber 76 behind piston 78.

Thus after the spool valve 56 closes valve element 70 onto valve seat 72, the pressure in the air control line 60 and the chamber 76 will bleed down to atmosphere through the orifice 84 thereby reducing the pressure acting against the side 82 of piston 78 keeping the valve 16 closed. The valve 16 will open due to the pressure in the air manifold 14 acting on the back side 85 of the valve 16. If desired, solenoid valve 86 may be actuated to bleed off the pressure in air control line 60 to open the valve 16 more rapidly.

The opening of valve 16 allows the air to flow from the manifold 14 into the combustion chamber 12 and to build up pressure towards the pressure selected by the placement of the control arm 50.

The pressure in the air manifold 14 increases to substantially the pressure in the combustion chamber 12 and this pressure flows into line 58 of the air control line which connects to control valve 56. When the pressure in the combustion chamber reaches the selected control pressure the pressure on both sides 64 and 66 of the piston 62 in the valve 56 are substantially the same, and the ball 28 of the relief valve 26 is forced up off of its seat thereby dropping the pressure in valve 56 on side 64 of piston 62 whereby the piston 62 moves the valve element 70 away from valve seat 72 opening the communication between lines 58 and 60. Pressure flows into chamber 76 and acts against the side 82 of piston 78 and since this area of side 82 is greater than the area of side 85 on the back side of inlet valve 16 the valve 16 will be closed. This allows the pressure in the air supply manifold 14 to build up rapidly to the supply reservoir pressure, and the valve 16 remains seated with any further increased pressure in the air manifold 14.

It is noted that when the valve 16 is seated and closed that the valve stem 80 actuates and closes a normally open microswitch 90. The microswitch 90 is connected in the ignition system of the apparatus 10 thereby insuring that the valve 16 is closed before the combustion chamber 12 is fired. And as described in the copending U.S. Pat. No. 3,461,577 a plurality of combustion chambers may be connected together as shown therein to be actuated simultaneously, and in such event each would be provided with a microswitch 90, all of which would be connected in series in a common ignition system.

After the combustion chamber 12 is fired, the solenoid valve 86 is actuated to open and vent control line 60 thereby reducing the pressure on side 82 of the piston 78 and permitting the vale 16 to open due to the pressure acting on the side 85 of valve 16. Also, due to the pressure drop in line 58 the ball 28 of the relief valve 28 is seated and the piston 62 is actuated by the force acting on the larger side 64 to close the valve element 70 on the seat 72. Solenoid 86 is then closed and the pressure now again builds up in the combustion chamber 12 and the cycle is repeated after the pressure in the chamber 12 reaches the pressure selected by the control arm 50.

Thus the present air control system provides positive closing of the air intake valve 16 prior to ignition of the combustion chamber and the combustion chamber is charged to the pressure preselected by movement of the control arm 50.

In use, an operator may, by actuation of the control lever 50, move the roller 46 in the direction 52 to increase the force keeping the ball valve 28 seated on seat 30 or move the control lever in the direction 54 to decrease the force keeping the ball sea thereon thereby regulating the pressure at which air will bleed out of line 32 through the relief valve 26. Therefore, the relief valve 26 by connected to the line 32 regulates the pressure that is developed on side 64 of the piston 62 in the control valve 56.

If the pressure selected by the actuation of the control arm 50 is greater than the pressure in line 32, the spool valve 56 closes closing the valve element 70 on the seat 72 preventing any further buildup in pressure in line 60. As the air in the chamber 76 then bleeds down through orifice 84, the pressure acting against side 82 on the piston 78 will decrease, an the air inlet valve 16 will open. The pressure in the combustion chamber will then build up towards the pressure selected by the control arm 50. As the selected control pressure is reached, the pressure on side 64 of the piston 62 in control valve 56 increases so that the ball 28 on relief valve 26 is forced off of its seat thereby causing a pressure drop on side 64 of piston 62 causing spool valve 56 to open and move valve element 70 off of seat 72. The pressure from the air manifold 14 will pass through line 58 into line 60 against the piston 78 closing valve 16, and closing microswitch 90 to indicate that the combustion chamber is now pressurized to the pressure selected by the control arm 50.

After the combustion chamber 12 has been fired, solenoid 86 is actuated to blow down the pressure in line 60 and the pressure in chamber 76 and opening valve 16. The pressure again builds up in the combustion chamber 12 and the cycle is repeated after the pressure therein reaches the selected pressure set by the control arm 50.

The present invention, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned as well as others inherent therein.

Claims

What we claim is:

1. In an apparatus for displacing material having a combustion chamber, a fuel inlet, air supply for supplying air to an air inlet therein, an ignition circuit for creating an explosion therein, and an outlet for directing the explosive forces against the material to be displaced, the improvement in a control system for controlling the admission of air into the combustion chamber comprising,

an air inlet valve between the combustion chamber and the air supply controlling the admission of air into the chamber,

a relief valve,

means for adjusting the pressure at which the relief valve opens,

a control valve connected to and responsive to the relief valve,

an air control line in communication with the air supply and the flow of air therethrough controlled by the control valve,

a piston connected to the air inlet valve and exposed on one side to the pressure in the air control line whereby any pressure exerted thereon acts in a direction to close said inlet valve, and

air bleed means connected to the air control line downstream from the control valve bleeding said line.

2. The apparatus of claim 1 wherein the means for adjusting the pressure at which the relief valve opens includes,

a beam one end of which engages and controls the relief valve,

a spring yieldably acting against the other end of the beam, and

a cam movable along the beam for varying the force of the beam acting on the valve.

3. The apparatus of claim 1 wherein the control valve includes a piston the first side of which is larger than the second side, and the first side being in communication with the relief valve, the second side being in communication with the pressure in the air control line and an orifice communicating between the first and second sides of said piston.

4. The apparatus of claim 3 including,

a spring acting against the first side of said piston in a direction to close said valve.

5. The apparatus of claim 1 wherein the air bleed means includes,

a solenoid actuated valve.

6. The apparatus of claim 1 including,

an electrical switch in said ignition circuit and positioned to be actuated by said air inlet valve when the valve is in the closed position.

7. The apparatus of claim 3 including,

an electrical switch in said ignition circuit and positioned to be actuated by said air inlet valve when the valve is in the closed position.

8. The apparatus of claim 7 wherein the air bleed means includes,

a solenoid actuated valve.

9. The apparatus of claim 1 wherein the air bleed means includes,

a bleed orifice.