US2853212A

US2853212A - Compression sprayer

Info

Publication number: US2853212A
Application number: US540390A
Authority: US
Inventors: Donald H Anderson
Original assignee: HD Hudson Manufacturing Co
Current assignee: HD Hudson Manufacturing Co
Priority date: 1955-10-14
Filing date: 1955-10-14
Publication date: 1958-09-23
Anticipated expiration: 1975-09-23
Also published as: ES231165A1; FR1158277A

Description

Sept 23, 1953 D. H. ANDERSON 2,853,212

COMPRESSION SPRAYER Filed Oct. 14, 1955 l .L l n United States Patent() CMPRESSION SPRAYER Donald H. Anderson, New Lenox, Ill., assignor to H. D.

Hudson Manufacturing Company, Chicago, Ill., a corporation of Minnesota Application ctober 14, 1955, Serial No. 540,390

19 Claims. (Cl. 222-402) The present invention relates to compression sprayers of the type provided With a tank for receiving and containing a spray solution and a removable pump assembly mounted within the lling opening of the tank, and is directed more particularly to a novel means and manner of detachably mounting and sealing the pump assembly in the tank, and to a novel check valve for controlling the ilow of air under pressure from the pump barrel on the downstroke of the pump plunger and sealing the barrel against the escape of air pressure from the tank into the pump barrel on the upstroke of the plunger and during operation of the sprayer.

As compression sprayers operate under substantial air pressure that must be built up in the tank by the pump to permit such sprayers to then effectively and continuously operate for a substantial period of time, much time and ettort has been expended and substantial expense incurred in the design and construction of compression sprayers in an attempt to provide for- (l) Quick and easy insertion and retention of the pump assembly in the tank;

(2) Positive sealing of the pump assembly in the tank;

(3) Quick release and removal of the pump assembly for replenishing the tank with a liquid or spray solution when the supply therein has been exhausted;

(4) Means whereby to release the contained pressure in the tank prior to removal of the pump assembly and thereby prevent forcible ejection of the pump assembly from the tank by the entrapped pressure which may cause injury to the operator.

The present invention has for an object to provide a simple and most effective means and manner for inserting, mounting and retaining the pump assembly in the tank, positively sealing said assembly in the tank without the use of cams, levers, screw threads or the like, releasing the tank pressure to permit the subsequent removal of the pump assembly without danger of pressure induced forcible ejection of the assembly and nally enabling the speedy and easy release and removal of the assembly from the tank.

A further object of the present invention is to provide a novel pump unit or assembly having a pump cylinder and plunger capable of generating a requisite air pressure in the tank for continuous spraying, said cylinder having a protruded annular enlargement near the upper end thereof. An expansible elastic sleeve surrounding the upper end of the cylinder and adapted to be positioned over the protruded enlargement forms a most effective sealing contact between the cylinder protrusion and the neck of the filling opening in the tank. Such sealing contact is maintained and becomes more elective as pressure builds up in the tank.

The novel sealing arrangement also provides a quick release for relieving the pressure in the tank after which the pump assembly may be removed for access to the filling opening to replenish the supply of spray solution or liquid in the tank.

Another important object of the present invention is to Patented Sept. 23, 1958 provide a novel and simple form of check valve for controlling the flow of air under pressure from the barrel during pumping operation and for sealing the barrel against the escape therethrough of pressure in the tank during each upstroke of the pump plunger and during the spraylng operation.

A further object of the present invention is the provision in a compression sprayer of a pump unit including a cylinder having a protrusion adjacent each end thereof, the upper protrusion cooperating as previously stated with an expansible surrounding sleeve to provide a novel mounting and a seal between the cylinder and the neck of the tank, and also provide for the entrance of air into the cylinder beneath the plunger at the top of each piston stroke. The lower protrusion of the cylinder also has a dual function in that it prevents upward displacement of the elastic band or check valve mounted on the lower end of the cylinder, and also provides space for the expansion of the depending flange of the cup packing beyond the normal internal diameter of the cylinder at the end of each down or compression stroke.

Further objects are to provide a construction of maximum simplicity, eiiciency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.

In the drawing:

Figure 1 is a view in vertical cross section through a compression sprayer and pump assembly embodying the present invention, the pump assembly being in position to be lowered into operative position in the tank or container.

Fig. 2 is a view similar lto Fig. l, but with the pump assembly in its lowered operative position in which the pump is anchored in sealing engagement in the neck of the tank.

Fig. 3 is a top plan view of the assembled compression sprayer with the handle moved or rotated to carrying position. v

Fig. 4 is a fragmentary enlarged view in vertical cross section through the upper end of the pump cylinder show- Iing the lower end of the plunger.

Fig. 5 is a fragmentary enlarged view in vertical cross section through the lower end of the pump cylinder provided with my novel check valve, the pump plunger being near the lower end of its downstroke.

Referring more particularly to the disclosure in the drawing and to the novel illustrative embodiment therein shown, the novel compression sprayer assembly comprises a tank or container 10 adapted to receive and contain a quantity of liquid or spray solution supplied thereto through the opening 11 from the upwardly ared pour- ICC -ing funnel 12 of the tank. Fig. l shows the pump unit 13 in position to be lowered and assembled in the tank in the operative position of Fig. 2.

The pump unit or assembly 13 comprises a pump cylinder or barrel 14 in which is slidably mounted a plunger including a piston rod .15 projecting through and guided bya cap or closure 16 at the upper end of the cylinder and a piston including a cup packing 17 having a depending and outwardly ared annular llange 18, anchored between an upper plate 19 and a lower inverted cup member 21.

To lock or retain the piston parts on the lower end 24 of the piston rod 15, the latter is threaded and the packing 17, the plate 19 and the inverted cup member 21 are provided with aligned openings to receive the threaded lower end 24 of the rod 15 on which these parts are secured by spaced lock nuts 25.

The member 21 includes a depending annular ange 22 adapted to abut in its lowermost position an end plate or closure 23 forming the lower end of the pump Cylinder 14, by which the downward movement of the plunger in the cylinder is limited. The depending ilange 22 is of such length as to prevent the depending liange 18 of the packing 17 from contacting the end plate 23.

The pump cylinder is expanded to form an annular enlargement or protrusion 26 adjacent its upper end, and also an enlargement 27 adjacent its lower end, for a purpose which will be later explained. Detachably mounted on the upper end of the cylinder 14 is the cap or plunger rod guide 16 which functions (l) to guide the rod 15 in the center of the cylinder 14, (2) to provide a closure for the upper open end of the cylinder to prevent the entrance'of foreign matter, and (3) carries an elastic expansible collar or sleeve 28 preferably formed of natural or compounded synthetic rubber and longitudinally movable on the cylinder 14. This eapansible collar 28 is adapted to surround and embrace the upper end of the pump cylinder and the upper end of the collar is aixed or anchored to the cap or closure 16 by being clamped between an insert or disc 29 and an external depending flange 31 on the cap or closure 16.

The closure 16 and the insert 29 have aligned, centrally arranged openings through which loosely projects the piston rod 15 so as to be freely reciprocable in the closure 16 to draw air into the cylinder upon manipulation of a handle 32 aflixed to the upper end of the rod 15.

When the plunger is elevated to its uppermost position, the cup packing 17 of the piston is in substantially the position shown in Fig. 4 wherein the packing no longer contacts the interior wall 33 of the pump cylinder 14 but enters the upper protrusion or enlargement 26 of the cylinder where the flange 18 of the packing 17 is spaced from the surrounding walls. Thus air is permitted to enter the cylinder by passing around the packing as indicated by the arrows in Fig. 4, whereupon as the plunger is pressed downwardly this air is forced from the cylinder into the surrounding space of the container.

To enable a pressure to be built up in the tank by reciprocation of the pump plunger and retained therein for discharging the spray solution through the tube 34 to a spray nozzle (not shown), I have devised a novel check valve to prevent back-How of pressure from the tank to the pump. This valve comprises a band 3S of an elastic, liexible material, such as natural or compounded synthetic rubber surrounding the lower end 36 of the cylinder 14 which is slotted or provided with openings about its circumference providing ports 37 for the discharge of air under pressure.

The elastic and compressible band 35 is held in operative position by the protrusion 27 above and the external ange 30 below on the closure 23. The band is contracted by slight tension and by the air pressure in the tank pressing it against the exterior of the cylinder 14 so that on the upstroke of the plunger, this valve member or band 35 effectively covers and seals the ports against reverse fluid flow from the tank into the pump cylinder. On the downstroke of the plunger, air under pressure is forced outwardly from the cylinder through the ports 37 and into the tank by stretching and temporarily expanding this valve member consisting of the band 35. This Y valve consisting merely of a exible band may be readily assembled on the cylinder and removed for cleaning or replacement. The cost of this valve is but a small fraction of the cost of prior types of mechanical valves ernployed in compression sprayers.

To mount or assemble the present novel pump unit 13 in the tank 10 and to effectively seal it for operation after each filling of the tank for which the pump unit or assembly must be removed for access to the filling opening of the tank, the pump cylinder 14 is provided at its upper end with the flexible collar or sleeve 28 and at its lower end with a coil spring 38 suitably axed at one end to the end plate or closure 23 of the pump cylinder. Upon insertion of the pump unit or assembly 13 to the position shown in Fig. l with the collar 28 encompassing the upper end of the cylinder 14, the handle 32 is turned to the position shown where the curved upper end 39 of a pair of hook members 41 is adapted to engage or be received in aligned grooves or recesses 42 in the base or underside of the handle 32. In this position, pressure may be applied to the handle and simultaneously to the hooks which are adjustably secured to the insert or disc 29 of the closure 16, whereby the collar or sleeve 28, being a close fit around pump cylinder 14, presses downwardly against the protrusion 26' thereby forcing the cylinder assembly downwardly in the tank 10 until the spring 38 is completely compressed or the resistance offered therebyis greater than the frictional resistance of the collar 28 to sliding movement on the cylinder 14. At such time the protrusion 26 of cylinder 14 is within tank 10, below the opening 11. Continued downward pressure on handle 32 opposed by the now immobile cylinder 14 forces the collar 28 to expand and slide downward over protrusion 26, thus increasing the outer diameter of the annular enlargement so that it cannot be withdrawn through opening 11.

Upon release of downward pressure applied to the handle 32 and to the cap or cover 16, the expansible coil spring 38 will force the pump unit or assembly 13 upwardly and with the air pressure within the tank 10 effectively seal the pump barrel or cylinder 14 in the neck of the inlet or filling opening 11, with the elastic collar 28 wedged between the enlargement on the cylinder and the throat 43 of the tank. With the collar 28 in the sealing and operative position of Fig. 2, the pump is prevented from being removed from the tank except as hereinafter disclosed. To now operate the assembled pump unit to build up air pressure in the tank, the handle 32 is rotated until it is disposed between the hook members 41, whereupon the handle may be manipulated to reciprocate the plunger.

If the compression sprayer is to be carried about, the handle 32 is rotated or moved to the position of Fig. 3 in which the base of the handle is engaged beneath the hook members 41 so that the tank and contents may be lifted and carried about by the handle.

To release the tank pressure prior to refilling the tank, the handle 32 is rotated or moved to the operative position shown in Fig. 2 wherein this handle is located between the spaced hook members 41. With both hands the operator then presses down on the handle 32 until the spring 38 is compressed sufiiciently to break the seal between the throat 43 -of the tank 10 and the collar 2S, whereupon the air pressure in the tank is relieved through the passage between the cylinder 14 and the surrounding` walls of throat 43.

To remove the pump from the tank the operator continues to press down on the handle with one hand and at the same time grasps with a linger of each hand one of the hook members 41 and pulls upwardly on these hook members until the elastic or resilient collar or sleeve 28 is withdrawn over the enlargement 26. Then with the resilient coll-ar or 'sleeve 28 in its elevated position on the pump barrel or lcylinder 14, downward pressure on the handle 32 may be relieved, thereby permitting the spring 38 to raise the released pump unit 13 in the inlet or filling opening of the tank to approximately the position shown in Fig. l. Thereafter, the entire pump assembly 13 may `be manually lifted out of the filling opening 1l of the tank 10.

By providing the pump cylinder 14 with protrusion 26 of somewhat smaller diameter than the lilling opening 1l and Iwith the novel resilient collar 23 carried by the cap or cover 16 and adjustable on the cylinder, a most effective sealing means is provided. Furthermore, this protrusion 26 provides a novel valve arrangement permitting free air to enter the cylinder 14 at the top of each upstroke of the plunger (Fig. 4). This is a highly important advantage over an 'air pump provided with a continuous cylindrical barrel wherein `as the plunger is drawn upward a partial vacuum must be created in the cylinder in order that air at atmospheric pressure may enterv around the plunger leather and into the cylinder below the plunger. With the present pump unit when the plunger is elevated to the position shown in Fig. 4, air at atmospheric pressure can freely enter the cylinder 14 about the cup packing, thus assuring the pump a full cylinder of air at atmospheric pressure `at the beginning ofeach stroke.

The hook members 41 are preferably threaded into the cap or cover 16 and the insert or disc 29 for longitudinal adjustment whereby their 'height may be varied. Lock nuts 44 lock these hook members in their adjusted position.

With the simple form of valve member disclosed in Fig. 5, no special valve seat or retaining means for the valve is required. There is but a single moving part, i. e., the `elastic or resilient band 3 which lencircles the lower end 36 of the pump barrel 14 under slight tension and forms an eifective seal on the upst-roke of the pump plunger by covering and sealing the ports 37 by its own elasticity and contraction and by the pressure in the tank. On the downstroke, this band permits the outilow of air through the ports 37 by stretching as the air under pressure is forced through these ports.

The lower enlargement Z7 of the pump cylinder has a two-fold function in that it retains the check valve member or elastic band 3S in position between it and the external iiange on the end cap or closure 23, and permits the annular ange 18 of the cup packing 17 to expand into this enlargement `whereby the leather or composition of the packing is maintained supple and its life prolonged. As clearly shown in Fig. 2, this flange 1S of the packing 17 is held out of contact with the base or end plate 23 of the barrel 14 by the depending iiange 22 of the inverted cup member 21 formed of metal or `other rigid material suitable for the purpose.

From the above description and the disclosure in the drawing, it will be apparent that the pre-sent invention comprehends a novel pump assembly, a novel means and manner of sealing this pump assembly in the tank which assures optimum safety as the pump ycannot be withdrawn for illing the tank until al1 pressure is relieved in the tank, and a novel, simplified and highly eifective check valve for the pump.

Having thus disclosed the invention, I claim:

1. A compression sprayer` comprising a tank having a filling opening, a compression pump including a cylinder proportioned to Abe inserted through said opening into said tank, a `sealing sleeve surrounding the upper portion of said cylinder and also proportioned to be inserted through said opening, and means on said cylinder for enlarging said sleeve beyond the dimension of said opening whereby the opening may be closed to seal the tank.

2. A compression sprayer comprising a tank having a iilling opening, a pump cylinder having a closed lower end, a circumferential enlargement near each end and eX- haust ports in proximity to the lower enlargement, an elastic band surrounding the ported portion of said cyl-V inder biased to close said ports, a sleeve surrounding Vthe upper portion of said cylinder, and means whereby said sleeve may be adjusted longitudinally of said cylinder to cooperate with the upper cylinder enlargement in sealing said tank opening.

3. In a compression sprayer, a tank provided with a neck defining a filling opening, a pump unit removably mounted in the iilling opening and including a cylinder, and means for detachably mounting land sealing the cylinder in the neck of the tank, said means comprising a protrusion on the cylinder adjacent its upper end and an elastic collar slidably mounted on the upper end of the cylinder with its lower end adapted to be forced over the protrusion when the cylinder is lowered in the tank and the protrusion is disposed below the neck of the iilling opening whereupon the elastic collar is wedged between the protrusion and the neck of the tank when the cylinder is moved to operative position.

4. In a compression sprayer, a tank provided with a constriction defining a illing opening, a pump unit removably mounted in the filling opening and provided with a barrel, and means for detachably mounting and sealing the barrel in the constriction of the tank, said means comprising an enlargement on the barrel adjacent its upper end and of less external diameter than the constriction, an elastic collar slida'bly mounted on the upper Iend of the barrel `with its lower end adapted to be forced over the enlargement when the barrel is lowered in the tank and the enlargement is disposed below the neck of the filling opening whereupon the elastic collar is wedged between the protrusion and the neck of the tank when the barrel is elevated, and means for spring-biasing the barrel to elevated position.

5. In a compression sprayer, a tank provided with a neck deining a filling opening, a pump unit removably mounted in the lling opening and provided with a barrel, and means for detachably mounting and sealing the barrel in the neck of the tank, said means comprising a protrusion on the barrel adjacent its upper end having an external diameter `somewhat less than the internal diameter of the neck of the tank, a resilient sleeve adjustably mounted on the upper end of the barrel with its lower end adapted to be forced over the protrusion when the barrel is lowered in the tank and the protrusion is disposed below the neck of the filling opening, and a coil spring disposed below the lower end of the barrel and the bottom of the tank for spring-biasing the barrel to elevated position to wedge the resilient sleeve between the protrusion and the neck of the tank for sealing the interior of the tank.

6. In a compression sprayer, a tank provided with a constriction defining a filling opening, a pump unit removably mounted in the filling opening and provided with a cylinder having an enlargement adjacent to but spaced from the upper end of the cylinder with said enlargement conformably received within the constriction, and means for removably mounting the pump unit in the iilling open ing and providing sealing engagement between said enlargement and the constriction of the tank, said means inc-luding a resilient sealing `collar longitudinally adjustable on the outer end of the cylinder whereby when the cylinder is lowered into the tank with the enlargement disposed below the constriction of the tank and the resilient collar is forced downwardly over the upper end of the `cylinder with the lower end of the collar over the enlargement, the resilient collar is wedged between the enlargement on the cylinder and the neck of the tank when the enlargement is located immediately below the neck.

7. In a compression sprayer, a tank provided with a constriction defining a filling opening, a pump unit removably mounted in the filling opening and provided with a cylinder having `an open outer end and a protrusion adjacent to but spaced from its outer end with said protrusion capable of being received within the constriction, and means for removably mounting and sealing the pump unit in the filling opening with the inner end of the cylinder projecting into the tank, said means including a cover for the outer end of the cylinder, a resilient sealing collar carried by the cover and encompassing the outer end of the cylinder and longitudinally adjustable thereon whereby when the cylinder is projected into the tank with the protrusion located within the tank and adjacent the constriction and the cover is depressed to force the resilient collar longitudinally over the outer end of the cylinder and over the protrusion, said collar upon retroactive movement of the cylinder becomes wedged between the protrusion and the constriction of the. tank, and means for spring-biasing the cylinder to maintain the collar in sealing engagement between the protrusion on the cylinder and the constriction of the tank.

8. In a compression sprayer, a tank having a constriction providing a lling opening for the tank, a pump unit adapted to be mounted in the constriction and comprising a pump .cylinder having a protrusion adjacent the upper end of the cylinder, said cylinder being open at its upper end and provided with a closure at its lower end, a compression spring disposed between the closure and the bottom of the tank for spring-biasing the pump unit to elevated position, a cover for the upper open end of the cylinder and provided with a depending sleeve of elastic material encompassing and gripping the upper end of the cylinder but movable relative thereto whereby the cover and its sleeve are movable longitudinally of the upper end of the cylinder, said sleeve when the cylinder is lowered into the tank and the cover and cylinder are depressed against the compression spring to locate the protrusion on the cylinder below the constriction in the tank and the lower end of the elastic sleeve is slid downwardly over the protrusion, release of downward pressure on the cover and cylinder of the pump unit causes the compression spring to elevate the cylinder and wedge the elastic sleeve between the protrusion and the constriction whereby t anchor the cylinder of the pump unit in sealing engagement with the constriction in the tank.

9. In a compression sprayer, a tank having a constriction providing a illing opening, a removable pump unit including a pump cylinder adapted to be readily inserted into and removed from the constriction in the tank, a

pump plunger mounted in the cylinder and provided withY a handle for reciprocating the plunger to supply air under pressure to the tank, said cylinder having a protruded portion adjacent the upper end of the cylinder and an elastic sealing member slidably mounted on the upper end of the cylinder adjacent said protrusion and providing sealing engagement between the protrusion on the cylinder and the constriction of the tank when wedged therebetween, said sealing engagement being released when the pump handle is pressed downwardly to depress the cylinder whereby to relieve the pressure in the tank, after which the pump unit may be withdrawn.

l0. In a compression sprayer, a tank having a constriction providing a filling opening, a removable pump unit including a pump cylinder adapted to be readily inserted into and removed from the constriction in the tank and provided with a protrusion adjacent its upper end, a pump plunger mounted in the cylinder and provided with a plunger rod and a handle for reciprocating the plunger to supply air under pressure to the tank, a cap for the upper open end of the cylinder and providing a guide for the plunger rod and a cover for the top of the cylinder, a depending collar of an elastic material carried by said cap and encompassing and gripping the upper open end of the cylinder but longitudinally movable thereon and over the protrusion, a closure for the lower end of the cylinder, a compression spring between the closure and the bottom of the tank for spring-biasing the cylinder and pump unit to elevated position, hook members rigidly secured to and carried by the cover for the cylinder adjacent the plunger handle, said hook members being adapted to be depressed by the pressure applied to the handle when the pump unit is to be inserted into the tank, whereby the handle depresses the collar until the cylinder compresses the spring, said handle thereafter depressing the hook members to slide the elastic collar over the protrusion at the upper end of the cylinder, whereupon release of pressure applied to the handle permits the compression spring to elevate the cylinder and wedge the depending collar between the protrusion and the constriction of the tank, said sealing engagement being released when the pump handle is pressed downwardly with sufcient pressure to depress the cylinder and compress the spring whereby to break the sealing engagement and relieve the pressure in the tank, after which the pump unit may be withdrawn. A

l1. In a compressing sprayer, a tank having a lconstricted neck for receiving the spray solution to be dispensed, a pump unit for supplying air pressure to the tank and including a pump cylinder removably mounted in the constritced neck, a cap for said cylinder, a plunger for said cylinder having a rod mounted for reciprocation in the cap and cylinder and a handle for manipulating the rod and plunger, and means for detachably mounting and sealing the cylinder and pump unit in operative position in the constricted neck of the tank but permitting removal of the pump unit for replenishing the contents of the tank, said means including a protrusion `on the cylinder adjacent its upper end with said protrusion having an external diameter less than the internal diameter of the constricted neck to permit the cylinder to be lowered in the tank with the protrusion disposed below the constricted neck of the tank when the pump unit is mounted in operative position, and a resilient c-ollar carried by the cap and encompassing the upper end of the cylinder and adjustable oil the cylinder to slide over the protrusion and provide sealing engagement between the protrusion on the cylinder and the -constricted neck of the tank.

12. In a compression sprayer, a tank provided with a neck defining a iilling opening, a pump unit removably mounted in the filling opening and provided with a barrel, a plunger including a rod mounted for reciprocation in the barrel and a packing carried at the lower end of the rod and conformably received and longitudinally movable in the barrel for supplying air under pressure to the tank as said rod is reciprocated, said `barrel having a protrusion adjacent its upper end and an elastic collar slidably mounted on the upper end of the barrel with its lower end adapted to be forced over the protrusion when the barrel is lowered in the tank and the protrusion is disposed below the neck of the lling opening whereupon the elastic collar is wedged `between the protrusion and the neck lof the tank to provide a seal thereat when the barrel is moved to operative position, the internal diameter of said protrusion being greater than the external diameter of the packing to provide an annular space between the packing and the protrusion for the entrance of air under atmospheric pressure into the barrel at the top of the stroke of the plunger.

13. In a compression sprayer, a tank provided with a neck defining a tilling opening, a pump unit removably mounted in the tilling opening and provided with a barrel, a plunger including a rod and a packing carried at the lower end of the rod and conformably received and longitudinally movable in the barrel for supplying air under pressure to the tank as said rod is reciprocated, said barrel having an enlargement adjacent its upper end for receiving the packing at the top of the stroke of the plunger, said enlargement being of greater diameter than the packing to provide an annular space about the pack- Aing for the entrance ofvair under atmospheric pressure into the barrel at the top Iof the stroke of the plunger.

14, In a compression sprayer, a tank having a constriction providing a filling opening, an air pump mounted in the filling opening and provided with a cylinder depending into the tank and a pump plunger for supplying air under pressure to the tank, said cylinder having a protrusion adjacent its upper end and another protrusion adjacent its lower end, an elastic sealing collar encompassing the upper end of the cylinder and when the air pump has -been assembled in the constriction of the tank said sealing collar forms a tight sealing contact lbetween the upper protrusion on the cylinder and the encompassing constriction of the tank for anchoring the pump in the tank, said upper protrusion further providing the interior of thel cylinder with a passage for the entrance of air under atmospheric pressure into the cylinder about the pump plunger when the plunger reaches the top of its upstroke, the lower end of the cylinder below the lower protrusion having multiple openings providing discharge ports for the passage of air under pressure from the inand a check valve comprising an elastic band encompassing the cylinder about the discharge ports for controlling rllow through said ports, said lower protrusion providing space for the expansion of the pump plunger at the limit of its downstroke and retaining the elastic band on the cylinder.

15. In a compression sprayer, a tank provided with a neck dening a lilling opening, a pump unit removably mounted in the filling opening and provided with a cylinder, a plunger longitudinally movable in the cylinder for supplying air into the tank to build up pressure in in the tank, said cylinder having a closure at its lower end and an enlargement above said closure, discharge ports provided in the circumference of the cylinder adjacent its lower end between said enlargement and said closure for the passage of air from the cylinder into the tank on the downstroke, and a resilient band encompassing said cylinder and disposed about the discharge ports to prevent air in the tank from returning into said cylinder on the upstroke, said enlargement providing for expansion of the pump plunger at the limit of its downstroke.

16. In a compression sprayer, a tank having a constriction providing a lling opening, an air pump mounted in the lling opening and provided with a cylinder depending into the tank and a pump plunger for supplying air under pressure to the tank, said cylinder having a protrusion adjacent its lower end and a closure at the bottom of the cylinder provided with an external flange, the lower end of the cylinder below the protrusion having multiple openings providing discharge ports for the passage of air from the interior of the cylinder into the tank on each downstroke of the plunger, and a check valve comprising a compressible band encompassing the cylinder about the discharge ports for preventing the return of air from the tank into the cylinder, said protrusion providing space for the expansion of the pump plunger at the limit of its'downstroke and said band being retained tbetween said protrusion and the ange on said closure.

17. In a compression sprayer, a tank, a pump unit mounted in the tank and including a pump barrel depending into the tank, a pump plunger in said barrel for supplying air into the tank under pressure, said barrel having a closure at its lower end and enlargement above said closure, discharge ports in the barrel between said enlargement and said closure for the passage of air from the barrel to the interior of the tank under pressure, and a compressible band providing a check valve for said ports, said band encircling the barrel about said ports and maintained on the barrel whereby on the upstroke of the pump plunger said band covers the ports and the air pressure in the tank presses the band against the barrel thus forming the check valve to prevent the return of air into the barrel, and on the downstroke of the pump plunger the air under pressure in the barrel stretches the band sulciently to discharge the air through the ports into the tank, said enlargement providing space for the expansion of the pump plunger at the limit of its downward stroke.

18. A compression sprayer comprising a tank provided with an opening, a pump having a plunger provided with an operating handle and a cylinder extending through said opening and longitudinally movable therein, said cylinder having an annular enlargement adjacent its upper end movable through said opening, a spring at the lower end of said cylinder, and an expansible sleeve surrounding and longitudinally slidable on said cylinder and over said enlargement when said cylinder is inserted and lowered into said tank by downward pressure on said pump handle, and in this inserted and lowered position with the enlargement and the portion of the sleeve about said enlargement disposed within the tank, when downward pressure on said pump handle is released, the spring which is compressed between the lower end of pump cylinder and the bottom of tank elevates the cylinder and eiects sealing by pressing the sleeve about said enlargement upwardly against the tank opening, whereupon air pressure produced within the tank by operation of the pump increases the upward thrust of the cylinder against the tank opening, thus tightening the seal.

19. A compression sprayer comprising a tank provided with a 'illing opening, a compression pump cylinder insertable through said opening and means including a protrusion on said cylinder and a longitudinally slidable elastic sleeve surrounding the upper portion of said cylinder, said sleeve being extensible over said protrusion when the cylinder is lowered in the tank until the protrusion and surrounding portion of the sleeve is within the tank below the lilling opening, and means for elevating said cylinder whereby the portion of the elastic sleeve over said protrusion closes said opening and with the air pressure within the tank maintains sealing engagement.

References Cited in the tile of this patent UNITED STATES PATENTS 410,848 McHugh Sept. l0, 1889 1,971,727 Parrott Aug. 28, 1934 2,715,980 Frick Aug. 23, 1955 UNITED STATES PATENT oTTTCE CERTIFCATE @E CRECTIN Patent Nm 2,853,232 September 239 1958 n Donald Ha Anderson It is hereby Certified that error appears n the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected belowe Column 6, lines 69 and. '73, for "retroaotve" read retraotve n;

oolulrn 89 line 3, for "oonstritoed" u cone-triste f :ma

Signed and sealed this 6th day of January 1959.,

Attest:

KARL H, AXLTNE Attesting Officer ROBERT C. WATSON Commissioner of Patents