US1176998A - Automatic regulator for air-compressors. - Google Patents

Description

A. WARD & T. F. PENCE.

AUTOMATIC REGULATOR FOR AIR COMPRESSORS.

APPUCATION FILED APR. 6. 1914. 1,176,998. Patented Mar. 28, 1916.

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AUTOMATIC REGULATOR FOR AIR COMPRESSORS.

APPLICATION FILED APR. 16. 1914.

1., 176,998. Patented Mar. 28, 1-916.

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Jauulllllll A. WARD 8 T. F. FENCE. Auurmlc REGULATOR FUR AIR COMPRL'SSURS.

APPLICATION FILED APR. l5. WI 1. f r

. .lntvntvd Man. .28, 1916.

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ARTHUR WARD AND THOMAS FRANKLIN PENCE, 0F WEBB CITY, MISSOURI; SAID WARD ASSIGNOR TO SAID FENCE.

Specification of Letters Patent.

Patented Mar. 28, 1.916.

' Application filed April 16, 1914. Serial No. 832,335.

To all whom it may concern:

Be it known that we, ART UR VARD and Tnonas FRANKLIN PENCE, citizens of the United States, residing at "Webb City, in the county of Jasper and State of Missouri, have invented certain new and useful Improvements in Automatic Regulators "for Air-Compressors: and we do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to air pumps, and more especially to those employed for compressing air; and the object of the same is to produce an improved automatic regulator whereby the load on an air compressor Will be relieved or released at both the inlet and outlet ends of the same in the event of excessive pressure in the receiver. This object is carried out by the details hereinafter more fully described and claimed and as shown in the drawings wherein Figure 1 is a side elevation of a constant speed air compressor with our automatic regulator applied; Fig. 2 is a central vertical section of the throttle valve; and Fig. 3 is an end elevation thereof; Fig. 4 is a diagrammatic sectional view showing more clearly the general arrangement of our regulator; Fig. 5 is a side elevation of the release valve; and Fig. 6 is a vertical section thereof; Fig. 7 is a vertical section of a modified form of release valve; and Fig. 8 is a side elevation of the same.

It is well known to those familiar with the action of air compressors that when the valves in the various cylinders commence to leak from any cause or when any other untoward conditions arise the pressure in the machine increases above that to which it is desired to raise it, heat is generated and the temperature rises rapidly, and eventually gases are produced and an explosion occurs which wrecks the machine and endangers the life of the operator. Experience has demonstrated the fact that these explosions occur at a time when the machine is running with the intake closed and is not making air, and therefore although the usual conditions may be known to exist it is dangerous to retard the speed of the machine and stop its-action because in slowing it down an explosion may occur.

It is the purpose of the present invention to take the load off the machine at such times by first reducing the inlet of air at the intake end of the machine and then relieving the machine at the outlet end thereof by releasing pressure in the last cylinder so that the compressed air and the gases referred to are delivered from the high pressure cylinder or pump into the atmosphere rather than into the receiver. This object we accomplish by utilizing the excessive pressure in said receiver to actuate the devices hereinafter described, and therefore to the extent that this excess of pressure is taken from the receiver the latter also is relieved of unusual strain. It results that our regulator quickly and automatically alters conditions at three points in the air compressor, with the result that, whether the machine continues to run or the operator slows it down to stop it entirely, the danger of accident has been reduced to a minimum and no catastrophe will occur. \Ve find in practice that the use of this regulator frequently tides over unusual conditions, so that after it has acted and its parts are restored to their normal position, the aircompressor continues its work uninterruptedly.

In the accompanying drawings we have shown our device as applied to a constant speed air compressor having a high pressure cylinder and a low pressure cylinder, but these cylinders will be called pumps in the following specification in order to avoid confusion with other elements which We prefer to designate as cylinders.

The letter I has been employed to designate the. intake, whence the air passes through a balanced valve or throttleT to the low pressure pump L, thence it is conveyed by the intercooler C to the high pressure pump H, and from the latter it passes through the outlet 0 to the receiver R which carries a pop-valve or safety valve S of any well known type. The two pumps are illustrated herewith as driven by any suitable motivepowerM. Thepartsasthusfardescrihed are not claimed to be new and, are illustrated herewith only for the sake of showing how our improved regulator is applied.

oming now to the details of the present invention, an upright cylinder 1 is support- 1 ed by a framework 2 mounted on the casing 3 of the throttle valve T, and within said cylinder moves a piston 4 which is connect ed withthe valve stem 5 of said throttle. Through said framework 2 passes a yoke 6 securedto-said stem,.and the ends of this yoke are connected by springs 7 with another yoke 8 overlying the cylinder '1, so that the tendency of the springs is to, raise the stem and open the throttle valve T. The latter is by preference of the balanced type as shown, and when closed or partly closed it throttles the inlet through the intake pipe I, and to a greater or less degree cuts off the admission of air to the low pressure pump L.

While we haveshown the receiver R as provided with a safety valve S as usual,this element may be employed or not as preferred; but the outlet therefrom or the outlet from the receiver R is in the present instance by means of a pipe 10 which leads into the inner end of a cylinder 11 which may well be mounted in a horizontal position on the top of the cylinder 1 as shown. Said cylinder carries a piston 14: whose stem 15 projects out the end of the cylinder and contacts with a bell crank lever 13 which is pivotally mounted on a bracket supported by the cylinder 11, the outer arm of this lever carrying an adjustable weight 12 as shown. This weight is set at the desired point, and it results that when the pressure in the receiver R exceeds that which the weight exerts it will flow through the pipe 10 (whether the safety valve S is employed or not) and will move the piston 14 outward so that its stem rocks the hell crank lever 13 on its pivot and raises the weight. The stem 15 is continued through the piston head 14 and reduced at its inner end so that it constitutes a needle as at 16, the same closing a port 17 when the weight 12 descends; and the relative arrangement of the two cylinders l and 11 is such that this port establishes communication between the pipe 10 and the interior of the cylinder 1. The port 17 communicates with a vent 18 which is by preference formed in the head of the cylinder 1 and is of quite small size. The result is that the excessive pressure within the receiver, after it has moved the piston 14: outward against the tendency of the weight 12, flows through'the port 17 and vent 18 into the top of the cylinder 1 above the piston a therein, and the latter -is caused to move downward against the tension of thesprings 7 so that the throttle valve T is closed to a greater or lesser degree. If the excessive pressure within the receiver is small, the throttle will doubtless be closed only partly; but if the excess of pressure therein should be considerable, as it probably will be if untoward conditions arise within the air compressor, the piston 4 will be borne downwardand the throttle T completely closed so that thereafter the low pressurepump L is working on a vacuum. This will continue as long as the-throttle is closed, but the vent 18 permit the slow escape of the compressed air within the head of the cylinder 1 above its piston 4, and therefore the excessive pressure within the receiver R is being relieved as long as the piston 4 is held down and the throttle is closed. As soon as said excess of pressure is relieved to a sufficient extent, the weight 12 descends and the bell crank lever 13 moves the stem 15 inward so that the needle 16 closes the port 17 and cuts off the supply of pressure through the pipe 10; after which the vent 18 permits the slow escape of air above the piston 4 and the latter rises under the tension of the springs 7 to reopen the throttle T and permit the machine to again take air through the inlet I.

If the air compressor is of that type which employs double-acting pumps. both ends of the high pressure pump H will be connected with the outlet pipe 0 which leads to the receiver'R; and that untoward conditions in this pump may be immediately relieved it is preferred that each end of' the pump shall have a relief valve whose construction will now be described.

The numeral 20 designates the valve casing, one arm 21 of which is connected with the interior of the high pressure pump, and the other arm 22 of which leads to an exhaust such as the atmosphere. The valve seat is formed in a bridge within this casing and the valve head 21 rests upon said seat and is normally held upon the same by means of a spring 25 whose tension may be adjusted in any suitable way as by means of a set screw 26. The valve is arranged to close upon its seat with the pressure which normally flows into the arm 21 and would escape out the arm 22 if the valve were open, and therefore the normal pressure within the high pressure pump tends to hold this relief valve closed. Carried by the valve casing 20 is a cylinder 27 within which moves a piston 28 whose stem 21') passes upward into the casing 20 and stands beneath the valve head. The lower end of the cylinder 27 is connected by a pipe 30 with a pipe line 31 which leads back past the air compressor and is tapped through the side of the cylinder 1 at a point 32.

When now the excess pressure within the receiver R forces the piston 4 downward to a point where the throttle valve T is closed, some of this pressure may escape through the pipe line 31 and its branches 30 into'each of the cylinders 27, and the piston 28 therein is raised so that its stem unseats'the valve 24 and the excess of pressure within the high pressure pump is ermitted to escape into the atmosphere ratlier than to flow into the receiver B. As soon as the excess pressure Copies of this patent may be obtained for overcome or relieve the untoward conditions which, as shown above, often give rise to serious accidents. The setting of the weight 12 controls the point at which the pressure within the receiver will cause the regulator to act, and if said receiverbe provided with a safety valve S the latter will doubtless be capable of adjustment in the usual manner. The setting of the screw 26 controls the point at which the relief valve 24 will open, and in fact this set screw may be adjusted so tightly that this valve will not open unless; the excess of air is exceedingly high. This is quite safe, for the unusual conditions are generally relieved by throttling the intake and permitting an exhaust of the excess of pressure within the receiver. It is considered to be an-important feature of the present invention, however, that the excess of pressure from the receiver admitted to the cylinder 1 which controls the throttle valve T, shall vent itself after the same has been controlled and therefore" allow parts to automatically restore themselves to their normal position. i

In Figs. 7 and 8 is shown a modified construction of the relief valve whose casing 40 has a globecheok valve G inits inlet arm 41, its outlet arm .42 being connected with the exhaust or the open atmosphere and its bridge 43 having a valve seat for the valve head 44 which closes with the pressure from the high pressure pump. The stem 45 of this valve projects upward through a twopart cylinder 46 provided internally at about its mid-length with a bridge 47 having an opening through which the stem moves loosely so that there can be a slight escape of air around it. The upper end of the cylinder is closed and the pipe line 30 opens through it as shown. Adjustably mounted on the stem 45 is a nut 48, between which and the bridge within the cylinder is a spring 49 tending to close the valve, while another spring 50 coiled on the stem beneath the bridge in this cylinder tends to open the valve. The action of this relief valve is substantially the same-as that of the valve described above. When pressure is admitted at the point 30 through the head of the cylinder 46, it bears downward on the upper end of the stem45 which therefore serves as a piston and assists the spring 50 in opening the valve 44. When the force of this excess of pressure has been exhausted, it leaks slowly out through the opening in the bridge 47 and eventually permits the springs to restore all parts of this relief mechanism to their normal condition.

What is claimed as new is:

The combination with a low pressure pump, a double acting high pressure pump, an inlet into the low pressure pump, a passage member leading from said low pressure pump to the intakes of the high pressure pump, a receiving chamber, and an airloutlet leading from both exhaust. ports of the double acting high pressure pump to'- said receiving chamber, of a throttle valve for the air inlet, a cylinder having therein a piston forv closing said throttle valve, a tube leading from the receiving chamber into the cylinder behind the piston, means normally obstructing communication between the receiving chamber and said cylinder and adapted to be released by excessive pressure in said chamber, whereby some of such pressure may flow into said cylinder to project the piston and thus close the throttle valve, a vent leading to the open air from said cylinder whereby some of the excessive pressure may escape, "a pair of relief valves for the two units of the double acting high pressure pump and having compartments into which pressure must be admitted to open said valves, an additional vent from the cylinder and exposed when the piston is projected to close the throttle valve, and a branched tube leading from said additional vent to said compartments, whereby to allow pressure to pass from Said cylinder into the aforesaid compartments to open the relief valves and thus allow the escape of air from the high pressure pump at two points while excessive pressure is escaping through the aforesaid vent, the compartments being so constructed as to allow the pressure received therein to escape, thus providing additional means for reducing the excessive pressure in the receivin chamber.

n testimony whereof we-have hereunto set our hands in presence of two subscribing witnesses.

ARTHUR WARD. THOMAS FRANKLIN FENCE.

Witnesses;

A. G. YOUNG, CARRIE YOUNG.

five cents each, by addressing the f0ommissioner of Patents, Washington, D. G."

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