Portable sprayer with improved combination of piston and diaphragm pump

• US 4,798,333 A
• Filed: 07/24/1987
• Issued: 01/17/1989
• Est. Priority Date: 05/31/1984
• Status: Expired due to Term

• Current Assignee: Pedro W. Luchsinger
• Original Assignee: Pedro W. Luchsinger
• Inventors: Luchsinger, Pedro W.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): Weldon, Kevin P.
• Application Number:
  US07/077,352
• Time in Patent Office: 543 Days
• Field of Search: 239/333, 239/330, 239/362, 239/142, 239/363, 411/373, 411/374, 92/102, 92/98 R, 92/99-101, 222/383
• US Class Current: 239/142
• CPC Class Codes: A01M 7/0017 Portable atomisers, e.g. knapsack type apparatus to be carried on or by a person B05B9/08
• CPC Class Codes: B05B 15/20 Arrangements for agitating the material to be sprayed, e.g. for stirring, mixing or homogenising
• CPC Class Codes: B05B 9/0877 the pump being of pressure-accumulation type or being connected to a pressure accumulation chamber

Abstract

A backpack agricultural sprayer has a pressure vessel mounted within a container and connected to a high pressure piston pump to force liquid into the pressure vessel from which it may be discharged for spraying. Leakage of liquid past the sprayer pump is contained by a leak-proof diaphragm which defines an agitation chamber connected by a conduit to the interior of the sprayer container. The diaphragm and piston are connected to be operated together to provide two separate but simultaneously acting pumps. The piston pump pressurizes the pressure vessel, and the diaphragm pump forces liquid back and forth between the container and diaphragm chamber to agitate contents of the container. An unique piston skirt is clamped by a single bolt between a skirt retainer and a piston body to provide a unitary assembly of diaphragm, piston body, skirt and skirt retainer. The skirt is resiliently urged outwardly to improve sealing and compensate for wear. The diaphragm chamber cover is threaded to the pump housing so that the cover may be removed for repair or replacement of the inner pump parts.

Claims

1. A liquid dispensing sprayer and liquid agitator for spraying insecticides, herbicides and the like including suspensions of wettable powders, comprising:

a container adapted to be carried on the back of a person,

a pressure vessel mounted within said container, and dual pump means connected to the container and pressure vessel for pumping liquid from said container into said pressure vessel and for agitating contents of said container, said pump means comprising;

a piston housing section,

a diaphragm housing section connected to one end of said piston housing section,

a housing cover connected and sealed to said diaphragm housing section and cooperating therewith to partly define an operating pump chamber,

a diaphragm extending across said pump chamber and having a peripheral edge captured and sealed between said cover and diaphragm housing section, said diaphragm cooperating with said diaphragm housing section to define an agitator pump chamber, and

a piston assembly secured to said diaphragm and slidably mounted within said piston housing section, said piston assembly comprising;

a piston body having a closed end,

a skirt retainer fixed to said piston body and having an outer annular surface,

a sealing skirt mounted on said outer surface of said skirt retainer, and

resilient means interposed between said sealing skirt and said skirt retainer for urging said skirt radially outwardly of said retainer,

valve means for connecting the interior of said piston housing section with the interior of said pressure vessel and with the interior of said container,

a discharge tube connected with the pressure vessel for spraying liquid under pressure,

an agitator conduit having a nozzle end in fluid communication with the interior of said container and having a pump end in fluid communication with said agitator pump chamber, and

means for concomitantly driving said piston assembly and diaphragm, whereby liquid under pressure is pumped from the container into the pressure vessel by the piston assembly, and the diaphragm draws liquid from the container into the agitator pump chamber and projects liquid from the agitator pump chamber back into the container in a high velocity stream.

2. The sprayer of claim 1 wherein said piston body has a forward end, said skirt retainer having an annular clamping shoulder facing the forward end of said piston body, said sealing skirt including a radially inwardly directed flange captured between said clamping shoulder and piston body forward end, and means for pressing said skirt retainer against the piston body to firmly clamp said skirt flange between the skirt retainer and piston body.

3. The sprayer of claim 2 wherein said means for pressing the skirt retainer against the piston body comprises elongated fastener means extending through said diaphragm and into said piston body for rigidly securing the piston body to the diaphragm, said skirt retainer including a holding portion thereof interposed between a portion of said elongated fastener and said piston body, whereby the fastener presses the skirt retainer toward the piston body end.

4. The sprayer of claim 3 wherein said piston body comprises a hollow piston cup having a closed end positioned against a central portion of the diaphragm, said skirt retainer comprising a hollow retainer cup having a body extending into said piston cup and having a closed end defining said holding portion, said closed end being adjacent to but spaced from the closed end of said piston cup, said skirt retainer having an enlarged forward end defining said clamping shoulder, said elongated fastening means comprising a bolt extending through said diaphragm and through the closed ends of said piston cup and retainer cup, and nut means on the end of said bolt within said retainer cup for pressing the closed end of said retainer cup toward the closed end of said piston cup to thereby press said clamping shoulder and skirt flange against said piston body cup.

5. The sprayer of claim 4 wherein said nut means comprises a nut threaded on an end of said bolt, a hollow nut cap fixed to the nut and having a closed end adjacent the open end of said hollow piston cup and having an open end with the retainer cup and adjacent the closed end of the retainer cup, and sealing means between the open end of said nut cap and said closed end of the retainer cup, thereby sealing said bolt from the interior of the piston chamber.

6. The sprayer of claim 5 wherein said sealing means comprises a deformable annular projection on the open end of said nut cap, and washer means positioned between said annular projection and the closed end of said retainer cup, whereby rotation of said nut on said bolt forces the end of said nut cap and said projection against said washer means to effect a tight seal between the nut cap and the inner closed end of the retainer cup and the bolt.

7. The sprayer of claim 1 wherein said diaphragm housing section includes an end having a threaded outer periphery and a clamping surface, and including means for clamping said housing cover and said diaphragm housing section together with said diaphragm peripheral edges clamped, said means for clamping comprises threaded means connected with said housing cover and threadedly engaged with said threaded peripheral of said diaphragm housing section.

8. The sprayer of claim 7 wherein said clamping surface of said diaphragm housing section includes a plurality of circumferentially spaced recesses spaced around the periphery thereof, and wherein said peripheral edge of said diaphragm includes a plurality of circumferentially spaced projections, each projection being received in a respective one of said recesses, whereby relative rotation of said diaphragm and said diaphragm housing section is restrained.

9. The sprayer of claim 7 including cooperating means on said diaphragm housing section and said diaphragm for restraining relative rotation of said diaphragm and diaphragm housing section.

10. The sprayer of claim 9 wherein said clamping means comprises an axially extending annular flange integral with the cover and having internal threads engaged with the threaded periphery of the diaphragm housing section, and wherein said cooperating means for restraining relative rotation comprises a plurality of circumferentially spaced recesses in said housing section and a plurality of projections on said diaphragm peripheral edge, said projections being respectively received in said recesses.

11. A dual pump comprising:

a pump housing having a piston housing section and a diaphragm housing section having a first peripheral sealing end,

a cover housing section connected to one end of said diaphragm housing section and having a second peripheral sealing end,

a stiff but resilient diaphragm having a peripheral edge captured between and sealed to said sealing ends,

means for pressing said sealing ends toward one another to clamp and seal said diaphragm peripheral edge therebetween,

a piston mounted within said housing sections and having a first end portion positioned at a central portion of said diaphragm, said piston cooperating with said piston housing section to form a piston chamber and cooperating with said diaphragm and diaphragm housing section to form a diaphragm chamber,

said piston having a second end remote from said diaphragm,

a skirt retainer connected to said piston and having a radially outwardly facing peripheral skirt mounting surface,

a sealing skirt extending about said skirt mounting surface,

bolt means extending through said diaphragm piston and retainer for fixedly securing together all of said skirt, retainer, piston, and diaphragm,

input and output passage means formed in said piston housing section for providing fluid communication with said piston chamber,

valve means for selectively blocking and unblocking said input and output passage means, and

port means for effecting fluid communication between said diaphragm chamber and an area external to said pump.

12. The pump of claim 11 wherein said skirt retainer comprises a cylindrical body having a first end positioned adjacent said first end portion of said piston, and having a second end adjacent said second end of said piston, said second end of said retainer having a clamp shoulder facing and spaced from said second end of said piston body, said skirt having an inwardly directed flange clamped to and between said retainer clamp shoulder and said second piston end.

13. The pump of claim 12 including means for resiliently urging said skirt radially outwardly relative to said skir mounting surface.

14. The pump of claim 11 wherein said piston comprises a hollow cylindrical body having a closed end positioned against a central portion of said diaphragm, and having an open end forming an annular clamping surface, said skirt retainer comprising a hollow cylindrical body having a closed end positioned within said piston body adjacent to but spaced from the closed end of said piston and having an open end, said open end of said skirt retainer including a radially outwardly extending enlargement forming a retainer clamp shoulder facing said piston clamping surface, said sealing skirt including a conical wall portion positioned against the outer surface of said skirt retainer enlargement, said skirt having an integral inwardly directed flange clamped between said retainer clamp shoulder and said piston clamping surface, and resilient means positioned between said conical wall portion of the skirt and said retainer enlargement for urging the skirt radially outwardly.

15. The pump of claim 14 wherein said bolt means extends through said diaphragm and through said closed end of said piston body for securing said piston to said diaphragm, said bolt means extending through said closed end of said skirt retainer, said bolt means including means for pressing said skirt retainer toward said piston body to thereby cause said retainer clamp shoulder to press said skirt against said piston body clamping surface, and to press said piston body against said diaphragm.

16. The pump of claim 14 wherein said bolt means extends through said diaphragm, through said piston body closed end, and through said retainer skirt closed end, said bolt means having a first fastening component positioned on a side of said diaphragm remote from said piston, and having a second fastening component positioned on a side of said retainer closed end portion remote from said diaphragm, said fastening components comprising means for urging said retainer toward said piston and diaphragm, thereby clamping said piston skirt and piston body between said retainer shoulder and said diaphragm.

17. The pump of claim 16 wherein said second fastening component comprises a nut threaded on said bolt shank and having a sealing nut cap fixed thereto, said bolt means having a threaded shank, said nut cap having a closed end remote from an end of said bolt and having an open end receiving said bolt end, said open end of said sealing nut cap including a longitudinally projecting sealing ridge, and a sealing washer circumscribing said bolt shank and interposed between said sealing ridge and the closed end of said skirt retainer, whereby said sealing ridge is pressed against said sealing washer to effectively seal the end of said bolt.

18. The pump of claim 17 including means for detachably connecting said diaphragm housing section to said cover section comprising an external threads formed on said sealing end of said diaphragm housing section, and an internal threaded flange fixedly connected to said cover housing section and threadedly engaged with said external threads.

19. The pump of claim 18 including means for resisting relative rotation of the diaphragm and said diaphragm housing section.

20. The pump of claim 19 wherein said means for resisting rotation comprises a plurality of circumferentially spaced recesses in said diaphragm section sealing end and a plurality of circumferentially spaced projections formed in said diaphragm and received respectively in individual ones of said recesses.