US1991403A - Pneumatic propulsion device - Google Patents

Description

Feb. 19, 1935. G, p, MGMANAMNA l PNEUIIATIC PROPULSION DEVICE Filed uy 1, 193s 'Il' Izarra 'rurali'.

Illllllllll' INVENTOR 6km-up P/Vc /VAfYnM/v/f Y MQW@ ATTORNEY Patented Feb. 19, 1935` UNITED STATES PATENT oFFlcE PNEUMATIC PBOPULSION DEVICE Gerald P. McManamna, Seattle, Wash. Application May l1, 1933, Serial No. 668,823 s claims. (o1. 3oz-5a) 'I'his invention relates to pneumaticpropulsion devices and it has reference more particularly to apparatus of that character whereby finely divided dry materials, fluid or semi-fluid materials may be fed from a source of supply into a delivery hose, or the like, and forcibly conveyed therein and discharged by an application of air under pressure supplied to the hose as a carrier for the material.

More specifically stated, the present invention relates to apparatus of the above character wherein the air propelled material is, for proper application, discharged through a spray nozzle at the end of the hose and wherein the entire operation is controlled from the nozzle.

The principal object of the present invention is to provide an apparatus of the above stated character comprising a closed container for a supply of the material to be discharged or distributed, means for'supplying air under pressure to the container for the propulsion of the materialinto and along the delivery hose to the nozzle, a valve device at the nozzle end of the hose operable to cut oi delivery of material therefrom and mechanism for feedingv the material into the hose that operates automatically for this purpose in accordance with the opening or closing of the said valve device.

It is also anl object of this invention to locate an engine within the container for actuating the means for feeding the material to the hose and which engine is operated by air delivered thereto under full pressure from the source of supply and automatically in accordance with a diierential in air pressure in the connection with the supply and in the container.

It is also an object of the invention to provide a pressure reducing means in the connection of the air container and air supply that operates to maintain" a constant delivery pressure of air in the container regardless of variation at the source of supply and which makes possible that diierential in pressures necessary for operation of the engine.

It is a further object of the invention to provide for a quick exhaustion of air under pressure for the container as a means of loosening material that may have become packed in the material containing compartment.

Other objects reside in the method of andv means for eifecting the automatic control of the device from the nozzle.

Other objects reside in the various detailsl of 5.5 construction, in the combination of parts and in their mode of operation, as will hereinafter be fully described.

In accomplishing these and other objects, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying'drawing wherein-' Fig. 1 is a longitudinal, sectional elevation of the material container embodied as a part of the present invention, together with the essential piping, feed mechanism and nozzle from which the material is pneumatically delivered.

Fig. 2 is a cross section on line 2-2 in Fig. 1".

Fig. 3 is a detail, showing the driving gearing for the feed screws.

Fig. 4 is a sectional detail of the nozzle.

It will be here explained that the present device has been designed especially for use in the extinguishing of fires. In its construction, provision has been made for feeding a finely divided dry chemical material into a hose for propulsion therefrom through a nozzle by air under pressure. 'I'he delivery hose may be of considerable length and control of the entire apparatus is automatic and under control of the nozzle mechanism. In the following description, the material to be sprayed or Ydistributed will be referred to as dust but it is to be understood that the apparatus is not confined only to this particular use or to the propulsion of this dry chemical, but is just as well applied to various other materials either dry or wet. For example, the mechanism is well suited for the propulsion of grain, concrete and like materials.

Referring more in detail to the drawing- 1 designates what preferably would be a cy-` lindrical, air tight tank or container disposed horizontally and divided by a transverse partition wall 2, at' one end of the tank, a compartment 3, designated as the motor compartment and at the other end a compartment 4 designated as the dust compartment; the latter, in this instance, being relatively large as compared to the former. At the top of the dust compartment is an opening 5 through which it may be filled, and removably tted to this opening is a closure member 6 of any suitable character.

At the base of the compartment 4 and adjacent one end thereof, is the dust outlet 7 communicating with a spout 8. The dust is fed from the tank to the outlet 7 by the operation of two spiral screws 9 9 disposed in parallel relation lengthwise of the tank and adjacent the bottom thereof as seen in Fig. 2. At their discharge ends, the conveyor mounting and driving shafts 9a and 9b are revolubly mounted in bearings 10 xed in the 2 end van of the ank. and at their opposite ends,

' these shafts extend revolubly through' packing conveyance of dust between them to the discharge opening '1. The driving means islan air motor 12 having a crank shaft 13 equipped at its lower end with a spiral gear wheel 14 which is disposed between and in mesh with gear wheels 15 and 15' ilxed, respectively, on the `ends'of the propeller shafts 9a and 9b within the motor compartment 3.

The air motor 12 maybe of any suitable character and operatively supported in any convenient or desirable manner. As here shown, it has two cylinders 16 and 16'., in which pistons 17 and 17 are reciprocally operable. The pistons are operatively. connected with the crankshaft 13 by connecting rods 18 and 18 and the shaft is rotatably supported in bearings as indicated at 19 and 19'.

The motor l2 is operated by air delivered to its inlet ports through a pipe 20 which extends through the top wall of the tank and connects directly with a pipe 21 leading from a source of compressed air. The operating air is exhausted from the cylinder of the motor 12 through a pipe 22 into the motor compartment 3. A port 23 in the upper portion of the partition wall 2 permits air pressure in' the motor compartment vto be communicated to the dust compartment 4.

A pipe 25 leads into the motor compartment from the air supply pipe 21 and interposed in this pipe is a pressure reducing valve 26 which operates to admit air from pipe 21 at a lower pressure into the motor compartment to maintain a certain predetermined propulsion pressure within the motor and dust compartments; this being substantially less than the pressure of air as communicated through pipe 21 to the motor 12, and provides a differential 'of air pressurebetween the motor supply and that of the motor'compartment which is necessary for operation of the motor.

'Ihe dust delivered from they compartment 4 by the feed screws passes through opening 7, into spout 8 and then is propelled by the air into a short pipe section 27 connected with the spout and containing a shut off valve 28 operated by a hand lever 29. Connected with the pipe 2'1 is a ilexible delivery hose 30 which may be of considerable length, and which is equipped at its end with a nozzle 31 containing a shut olf valve 32 as seen in Fig. 4, operated by a hand lever 33. A pipe 35 leads from the top of the dust compartment 4 into the pipe 2'1 at a point just beyond the valve 28 and through this pipe 35 secondary air may be admitted to the pipe 27 and there mixed with the dust and air passing the valve 28 and these combined streams of air under pressure operate to propel and forcibly deliver the dust in a spray from the nozzle. A valve 36 in pipe 35 may be adjusted to regulate ilow of air through the pipe.

There is also provided in the top of the tank 1 a blow olf valve 38 operated by a hand lever 39. This valve is of such size as to provide for a quick exhaust of all air from the tank as a method for loosening the dust should it become packed about the feed screws.

It will here be mentioned that while I have described the device as being operated by compressed air. it is to be understood that the operating medium maybe any drygas or a mixture of 1,r.'n,l4.os\- y 'gases which will have no chemical reaction on the dust when dry. Air has been mentioned as it is the medium which to my knowledge best fulillls the requirements.

It will also be mentioned that, for mechanical and practical reasons the two compartments 3 and 4 are formed within a single tank by dividing partition, however, if it should be found desirable, for any reason, these two compartments could be made-in separate containers and the operation would be the same so long as provision was vmade forcommunicating air pressure in the dust compartment to the motor compartment forcontrol of the motor and suitable drivingl connection was made between the motor and feed screws. The function of the partition wall 2 in the present instance is not primarily to provide two compartments but is to keep the dust from cloggingthe mechanism which operates the screws. Manifestly, it would be possible to eliminate the partition, provided that the engine was located in a position at which it would not be clogged with dust and satisfactory means was provided for operatively connecting it with the material feed mechanism.

Assuming the device to be so constructed, its operation would be as follows:

The dust compartment 4 is first filled through the opening 5 with a normal charge of dust. This charge would cover the vdust outlet and also the spiral conveyor screws to apdepth, which may be that as indicated in Fig. 1. The opening 5 is then closed by the cover 6 to seal the tank against leakage of air. Air under pressure is then introduced into the air supply pipe 21 and pressure in the motor compartment is raised to that predetermined amount controlled by the setting of the pressurereducing valve 26 through which air must flow to reach said compartments. Pressure introduced into compartment 3 is communicated to compartment 4, through the pipe or port 23. The pressure in the supply pipe 21 is communicated through the pipe 20 to the inlet ports of the motor l2. The differential of pressure in the pipe 20 supplying the motor 12 and that within the compartment 3 by reason of the pressure reducing .valve 26 permits the motor to operate and incident to this operation, exhaust air is discharged from the motor into the motor compartment. It is obvious, therefore, that the air motor tends to turn and to operate the spiral conveyor screws which in turn will force any dust surrounding them to a point over the dust outlet '1, where it can be discharged through the outlet by the air pressure existing in the dust compartment. The difference in air pressure existing between the dust compartment and the inlet ports of the motor is so regulated that sufficient torque is created by means of the air motor to keep the dust outlet of the tank covered with dust at all times during the discharge of the dust. Furthermore, if the discharge outlet is already covered, the spiral screws and therefore the air motor will not be permitted to operate due to the overcoming resistance applied to the screws by the packed dust surrounding them. Under the above conditions the dust is ready to be discharged through the spout 8, pipe 21 and hose 30 and this is permitted by opening the valve 32 in the nozzle, the secondary air valve 36 and the dust outlet valve 28 in the sequence named. When dust appears at the nozzle tip then the valve in the nozzle may be closed or opened to shut oil? or discharge the dust at will.

The device, so constructed, is automatically placed under control of the operating valve at the discharge end of the hose, that is, the valve contained within the nozzle, for the reason that when the nozzle valve is closed air pressure will be built up in the compartment 3 due to air exhaust from the motor and this pressure nally will become sumcient to balance-the pressure of the source of air supply in the pipe 20, therefore, the motor will cease to operate. As soon as the nozzle is opened, air is discharged through the hose, thus reducing the pressure in the dust and motor compartments and permitting the motor again to operate for y feeding the dust to the outlet.

Due-to the fact that somekinds of dust, which have qualities necessary for use in this machine, have a tendency to pack closely when allowed to remain undisturbed for very long, or when the vessel containing the dust is subjected to vibration, it will sometimes happen that the dust in this condition will produce sufficient friction that the spiral conveyor screws will not turn and means must be provided to overcome this diniculty otherwise air only will blow through the hose. This difficulty is overcome by placing the dust under high pressure and then quickly opening the blow off valve 38. This permits the air that is trapped in the dust to suddenly exparid and this sudden expansion will separate the particles of dust suiliciently to reduce the friction on the spiral conveyor to a degree Awhich will permit them to turn in their normal manner.

Devices of this character may be made in various sizes and shapes, and it is quite apparent that changes in details might be made to suit different materials. Therefore, it is not desired that the claims shall be limited in scope only to details shown, but shall be given an interpretation commensurate with the invention disclosed.

Having/thus described my invention, what I claim as new therein and desire to secureby Letters Patent is- 1. A device of the character described comprising a closed container for a supply of finely divided material, a discharge conduit leading therefrom, mechanism operable to feed material from said supply to the conduit, a sourceof fluid mediuml under pressure and an engine connected with said source and operable by application of the medium thereto for actuating said mechanism and arranged to exhaust the used medium therefrom into the container to create an expelling pressure against the supply of material.

2. A device of the character described comprising a closed container for a supply of finely divided material, a discharge conduit leading from the container, conveyer mechanism in the container operable to feed the said material to the conduit, means for closing the conduit against outflow, and an engine operable by application of a fluid pressure medium thereto for actuating the conveyer mechanism; said engine being arranged to deliver its exhaust charges into the container to effect the building up of a back pressure on closing the conduit, whereby the operation of the engine will be checked.

3. A device of the character described comprising a closed container for a finely divided material, a delivery conduit leading from the container, a conveyer mechanism in the container operable to deliver material into the conduit, means for admitting air from the container into the conduit for propulsion of the material therethrough, an engine o perable to actuate the conveyer, means for supplying operating air under pressure to the engine, means for supplying air at a lower pressure to the container and means for closing the conduit against outflow therethrough; said engine havingits exhaust ports opening into the container thereby to cause action of the engine to be influenced by pressure in the container.

4. A device of the character described comprising a closed container for a material to be dispelled; said container having an outlet and a delivery conduit leading therefrom to a point remote from the container, a control valve at the remote end of the conduit, an air pipe connecting the top of the container and the conduit at a point relatively close to the connection of the conduit with the container, conveyer mechanism within the Acontainer for feeding material into the outlet, an air engine enclosed within the container and operable to actuarte the conveyer, means for supplying operating air under pressure to the engine; aid engine having its exhaust ports opening i `o the contain r thereby providing thatpre medium exh usted by the engine be util@ d as a medium for expelling the material tlrough the conduit and upon closing the said control valve of the conduit to effect the building up of a back pressure for automatically i stopping the engine.

5. A device of the character described comprising a closed container for a material to be dispelled; said container having a base outlet and a delivery conduit leading therefrom, a nozzle at the end of the conduit and a control valve in said nozzle, an air pipe connecting the container and conduit, a valve in the conduit between said outlet and air pipe-connection, a conveyer in the container operable to feed material to the outlet, a source of compressed air, an engine in the container for actuating the conveyer, means for admitting operating air at full pressure from said source to the engine, and means for admitting air from said source at a lower pressure into the container; said engine having its exhaust ports opening directly into the container.

6. A device of the character described comprising a closed container, a partition in the container dening at one side an .engine compartment andv at the other side a compartment for material to be dispelled; said compartments having a communicating air port in the partition and said latter compartment having a discharge outlet, a conduit extending from said outlet, a control valve at the delivery end of the conduit, a conveyer in the container operable to deliver material to the outlet, an air pipe connection between the top of the material compartment and conduit, an air engine in the engine compartment having operative connection with the conveyer, a source of air pressure, a supply conduit from said source to said engine, a connection from said source opening into the container, a pressure reducing valve in the latter connection; said engine having its exhaust opening into the container thereby to cause the engine to operate under control of air pressure created in the container.

7. A device of the character described comprising a closed container having an end wall and having a base wall provided with an opening adjacent the end wall, a delivery conduit extending from the opening, a pair of parallel screw conveyers mounted in the container and terminating close to the end wall, means for actuating the conveyers to cooperate in the delivery of material between them from within the container into said opening and means at the end of the conduit for closing the conduit against outow.

8. A device of the character described comprissure, means connecting the engine directly with ing a closedl container having a base outlet tom said source for its operation, means for supplycontained material, an elongated conduit leading ing air at a predetermined lower pressure to the from the outlet, a nozzle at the end of the conduit, container, an air pipe leading from the container 5 a control valve in the nozzle, a. conveyer mounted :and connecting with the conduit beyond its con- 5l l in the container and operable to feed material to nection withthe container outlet, a valve in said theyoutlet, an air driven engine enclosed within pipe and a valve in the conduit between its concontainer and operatively connected with the nection withthe container outlet and the air pipe cnveyers; said engine having its exhaust openconnection therewith. -fo/ing into the container, a source of air under pres- GERALD P. MCMANAMNA. 1-0

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