EP0383029A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Pressure washer with bypass
Assignee: Shop Vac Corp
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Filing: 1990-01-16
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Granted: —
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Expires: 2010-01-16
Abstract
Abstract A pressure washer (10) for delivering a liquid under high pressure has an inlet conduit (30) connected to a liquid supply and an outlet conduit (50) coupled to a spray nozzle (18) which can be operated to control the delivery of liquid through the spray nozzle (18). Liquid, e.g., water, is pumped from the inlet (30) to the outlet conduit (50), elevating its pressure significantly. A bypass conduit (56) enables recirculation of the liquid from the outlet (50) to the inlet conduit (30). A bypass system (14), disposed between the outlet conduit (50) and the bypass conduit (56), includes a shuttle valve (70) which moves between first and second positions at which it respectively blocks or opens the liquid path from the outlet conduit (50) to the bypass conduit (56). The shuttle (70) is such that, when the liquid pressure on the side of the shuttle (70) facing the spray nozzle (18) is approximately equal to or greater than the liquid pressure in the outlet conduit (50), the shuttle (70) moves to a position which unblocks the bypass conduit (56), approximately equalizing the pressure across the shuttle (70) and protecting the washer's (10) components and enhancing its operability. A nozzle seal arrangement in the pressure washer's pump (12) comprises a pair of seals (230,236) between each piston (190) and cylinder (32) wall of the pump (12). One of the seals pivots in response to side to side wobbling of the piston (190) while maintaining proper sealing conditions.
Inventors
- 👤 Clive R. Paige
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 02:11
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/22; F04B49/24; B; B08; B08B; B08B3/00; B08B3/02; B08B3/026; B08B2203/00; B08B2203/02; B08B2203/0205; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86718; Y10T137/86759; Y10T137/86791; Y10T137/86799
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
283 words
A pressure washer for delivering liquid under pressure, the pressure washer comprising: a spray nozzle for spraying liquid; an outlet conduit connected for delivering liquid to the spray nozzle and an inlet conduit for receiving liquid from a liquid supply; a pumping means connected between the inlet conduit and the outlet conduit and effective for pumping liquid from the inlet conduit to the outlet conduit; actuation means associated with a spray nozzle for selectively permitting or blocking exit of liquid pumped by the pumping means from the spray nozzle; a bypass conduit connected between the inlet conduit and the outlet conduit in parallel to the pumping means; and a liquid bypass system associated with the bypass conduit for selectively closing and opening the bypass conduit, the bypass system including a bypass chamber, in liquid communication with the bypass conduit, and having a chamber inlet in fluid communication with the outlet conduit and a chamber outlet, the bypass system further including a shuttle moveable in the bypass chamber between a first position in which the shuttle blocks fluid communication between the bypass chamber and the bypass conduit and a second position which permits fluid communication between the bypass chamber and the bypass conduit; the shuttle having a first surface area exposed to liquid pressure at the chamber inlet and a second surface area exposed to liquid pressure in the chamber outlet, the first and second surface areas and the shuttle being so constructed and dimensioned that the shuttle becomes disposed in the first position when the liquid pressure at the chamber inlet is greater than the liquid pressure at the chamber outlet by a predetermined amount, and otherwise becomes disposed in the second position.
Claim 2
Dependent Claim
283 words
A pressure washer for delivering liquid under pressure, the pressure washer comprising: a spray nozzle for spraying liquid; an outlet conduit connected for delivering liquid to the spray nozzle and an inlet conduit for receiving liquid from a liquid supply; a pumping means connected between the inlet conduit and the outlet conduit and effective for pumping liquid from the inlet conduit to the outlet conduit; actuation means associated with a spray nozzle for selectively permitting or blocking exit of liquid pumped by the pumping means from the spray nozzle; a bypass conduit connected between the inlet conduit and the outlet conduit in parallel to the pumping means; and a liquid bypass system associated with the bypass conduit for selectively closing and opening the bypass conduit, the bypass system including a bypass chamber, in liquid communication with the bypass conduit, and having a chamber inlet in fluid communication with the outlet conduit and a chamber outlet, the bypass system further including a shuttle moveable in the bypass chamber between a first position in which the shuttle blocks fluid communication between the bypass chamber and the bypass conduit and a second position which permits fluid communication between the bypass chamber and the bypass conduit; the shuttle having a first surface area exposed to liquid pressure at the chamber inlet and a second surface area exposed to liquid pressure in the chamber outlet, the first and second surface areas and the shuttle being so constructed and dimensioned that the shuttle becomes disposed in the first position when the liquid pressure at the chamber inlet is greater than the liquid pressure at the chamber outlet by a predetermined amount, and otherwise becomes disposed in the second position.
Claim 3
Dependent Claim
25 words
The pressure washer of claim 1, further comprising a through-going liquid channel in the shuttle which extends from the first to the second surface area.
Claim 4
Dependent Claim
29 words
The pressure washer of claim 2, wherein the shuttle has a substantially circular cross-section, is constructed around an axis, and the liquid channel passes generally axially through the shuttle.
Claim 5
Dependent Claim
66 words
The pressure washer of claim 2, further comprising first and second seals disposed spacedly relative to one another and extending circumferentially around the shuttle, the first seal being effective to seal the chamber inlet from the bypass conduit in the first position of the shuttle and the second seal being effective to seal the chamber outlet from the bypass conduit in all positions of the shuttle.
Claim 6
Dependent Claim
52 words
The pressure washer of claim 2, wherein the bypass chamber has first, second and third axially extending and cross-sectionally differently-sized regions, the first region having a largest diameter, the second region having an intermediate diameter, and the third region having a smallest diameter and being disposed between the first and second regions.
Claim 7
Dependent Claim
19 words
The pressure washer of claim 5, wherein the bypass conduit meets the bypass chamber in the third region thereof.
Claim 8
Dependent Claim
67 words
The pressure washer of claim 6, further comprising a first seal which extends circumferentially around a portion of the shuttle which is movable between the first and third regions and a second seal extending circumferentially around the shuttle on another portion thereof which enables the second seal to remain at all times in sliding contact with a wall of the bypass chamber which defines the second region.
Claim 9
Dependent Claim
78 words
The pressure washer of claim 7, wherein the first position of the shuttle places the first seal in contact with a wall which defines the third region to block liquid communication from the bypass chamber to the bypass conduit and the second position of the shuttle places the first seal such that it faces but is spaced from a wall defining the first region in a manner permitting liquid flow from the bypass chamber to the bypass conduit.
Claim 10
Dependent Claim
13 words
The pressure washer of claim 2, wherein the shuttle has a circular cross-section.
Claim 11
Dependent Claim
13 words
The pressure washer of claim 2, wherein the shuttle has a non-circular cross-section.
Claim 12
Dependent Claim
33 words
The pressure washer of claim 4, further comprising a further liquid conduit debauching into the bypass chamber at the third region thereof and effective for introducing into the bypass chamber an additional fluid.
Claim 13
Dependent Claim
36 words
The pressure washer of claim 11, wherein the further liquid conduit is disposed at a location in the third region which is between the chamber outlet and the second seal, in all positions of the shuttle.
Claim 14
Dependent Claim
27 words
The pressure washer of claim 12, further comprising a one-way valve means effective for enabling fluid to flow unidirectionally, through the further liquid conduit, into the chamber.
Claim 15
Dependent Claim
25 words
The pressure washer of claim 2, wherein the bypass chamber is defined by a neck which extends from a housing associated with the pumping means.
Claim 16
Dependent Claim
22 words
The pressure washer of claim 14, wherein the neck comprises means for securing thereto a hose coupling associated with the spray nozzle.
Claim 17
Dependent Claim
135 words
The pressure washer of claim 2, wherein the pumping means comprises: a cylinder and a piston reciprocable within the cylinder, the piston having a peripheral wall and a cross-sectional size smaller than an interior diameter of the cylinder and a clearance between the cylinder and the piston; an annularly extending notch in the cylinder; a first sealing means in the notch and a second sealing means extending between the first sealing means and the peripheral wall of the piston, the second sealing means being partially disposed in the notch, the first and second sealing means being effective to enable the piston to wobble relative to an axis associated with the cylinder while maintaining a liquid seal between the first and second sealing means and between the second sealing means and the wall of the piston.
Claim 18
Dependent Claim
24 words
The pressure washer of claim 16, wherein the piston further comprises a cover around the piston, the cover comprising the wall of the piston.
Claim 19
Dependent Claim
22 words
The pressure washer of claim 17, further comprising a further sealing means disposed between the cover and a body of the piston.
Claim 20
Dependent Claim
36 words
The pressure washer of claim 17, further comprising a seal support disposed adjacent the first and second sealing means in a manner which is effective to retain the first and second sealing means in the notch.
Claim 21
Dependent Claim
24 words
The pressure washer of claim 16, wherein the pumping means comprises a plurality of cylinders and a respective piston for each of the cylinders.
Claim 22
Dependent Claim
231 words
A pressure washer for delivering liquid under pressure, the pressure washer comprising: a spray nozzle for spraying liquid; an outlet conduit connected for delivering liquid to the spray nozzle and an inlet conduit for receiving liquid from a liquid supply; a pumping means connected between the inlet conduit and the outlet conduit and effective for pumping liquid from the inlet conduit to the outlet conduit; actuation means associated with a spray nozzle for selectively permitting or blocking exit of liquid pumped by the pumping means from the spray nozzle; a bypass conduit connected between the inlet conduit and the outlet conduit in parallel to the pumping means; a cylinder and a piston reciprocable within the cylinder, the piston having a peripheral wall and a cross-sectional size smaller than an interior diameter of the cylinder and a clearance between the cylinder and the piston; an annularly extending notch in the cylinder; a first sealing means in the notch and a second sealing means extending between the first sealing means and the peripheral wall of the piston, the second sealing means being partially disposed in the notch, the first and second sealing means being effective to enable the piston to wobble relative to an axis associated with the cylinder while maintaining a liquid seal between the first and second sealing means and between the second sealing means and the wall of the piston.
Claim 23
Dependent Claim
231 words
A pressure washer for delivering liquid under pressure, the pressure washer comprising: a spray nozzle for spraying liquid; an outlet conduit connected for delivering liquid to the spray nozzle and an inlet conduit for receiving liquid from a liquid supply; a pumping means connected between the inlet conduit and the outlet conduit and effective for pumping liquid from the inlet conduit to the outlet conduit; actuation means associated with a spray nozzle for selectively permitting or blocking exit of liquid pumped by the pumping means from the spray nozzle; a bypass conduit connected between the inlet conduit and the outlet conduit in parallel to the pumping means; a cylinder and a piston reciprocable within the cylinder, the piston having a peripheral wall and a cross-sectional size smaller than an interior diameter of the cylinder and a clearance between the cylinder and the piston; an annularly extending notch in the cylinder; a first sealing means in the notch and a second sealing means extending between the first sealing means and the peripheral wall of the piston, the second sealing means being partially disposed in the notch, the first and second sealing means being effective to enable the piston to wobble relative to an axis associated with the cylinder while maintaining a liquid seal between the first and second sealing means and between the second sealing means and the wall of the piston.
References Cited (Backward Citations)
US4976467A
Cited
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