EP1511575B1

EP1511575B1 - Adjustable flow texture sprayer with peristaltic pump

Info

Publication number: EP1511575B1
Application number: EP03737034A
Authority: EP
Inventors: Robert Gundersen; James Schroeder; David Thompson; Dale Johnson
Original assignee: Graco Minnesota Inc
Current assignee: Graco Minnesota Inc
Priority date: 2002-06-13
Filing date: 2003-06-13
Publication date: 2009-01-14
Anticipated expiration: 2023-06-13
Also published as: US20050254879A1; EP1511575A1; CN100421812C; CN1658977A; EP1511575A4; KR20050013569A; WO2003106042A1; DE60325850D1; AU2003238010A1

Description

BACKGROUND ART

Texture sprayers have traditionally ranged from simple guns having top-mounted hoppers (hopper guns) to progressive cavity pumps which can pump large amounts of material substantial distances at substantial cost and weight.
Prior art peristaltic pumps are provided with a rotor having two (or more) rollers, the rotor being capable of rotation in either direction while a tube or hose is stretched across a distance. This creates kinks or closures in the tube at the points of roller contact. As the rotor revolves, the kinks travel with the rollers providing a positive displacement of the fluid contained between the kinks. Most such pumps provide a follower plate which sandwiches the hose between itself and the rollers.
FR 1213896 discloses a pump comprising a support, a tube attached to the support, a rotor and a plurality of cams attached to the rotor. The rotor may be driven by a motor. The rotor is pivotally mounted to the support via a movable arm and a spring is mounted between the support and the movable arm so as to pull the rotor against the tube. FR 1213896 also discloses a pump in which a U-shaped length of tubing is wrapped around a rotor comprising two rollers. The ends of the tubing are attached to a frame and the rotor is fixed to the frame by an arm.

DISCLOSURE OF THE INVENTION

According to an aspect of the present invention, there is provided a sprayer for application of viscous materials such as texture, said sprayer comprising:

a frame; a loop of tubing having first and second ends and being attached to said frame; a motor, said motor having a shaft with a rotor attached thereto, said motor being pivotably attached to said frame to vary the distance between said shaft and said first and second tubing ends; a plurality of rollers attached to said rotor and engaging said tubing; and characterised by a force generator attached between said motor and said frame, the force generator being adapted to vary the force with which said rollers contact said tubing.

It is a desire to have a small, relatively inexpensive and self-contained texture sprayer. A cart contains one or more adjustable flow peristaltic pumps, a motor (electric or gas), a material supply hopper and a flow control device. A double-ended motor shaft may be provided wherein one end drive the peristaltic pump and the other end drives an air compressor.
This apparatus may also be provided without the compressor where the user will supply atomization air. A texture spray gun is provided with a small hop so that it may be used either independently or with the cart mounted material supply. Another version may be provided with a separate compressor having its own motor for independent operation of material and air.
It has been found that the peristaltic pump provides a unique vibration which enhances the flow of high viscosity materials such as texture by loosening the bond between the hose and the high viscosity materials as well as self-cleaning the hopper. The pump may be run forward or reverse with reverse being used to empty the hose or transfer material.
The hose retention mechanism on the peristaltic pump consists of a coupled hose, a hose retainer plate, a mounting plate and a retainer screw. A hose with couplings slides onto each end of the hose retainer plate. The hose retainer plate is secured to a mounting plate or surface with a fastener while the hose couplings protrude through the surface of the mounting plate for access. The hose retainer plate supports the downward loads imposed by the peristaltic pump while the mounting plate or surface keeps the coupled hose in proper alignment in the pump. Matching the profile of the fittings (e.g. hexagon) with the opening of the mounting plate or surface prevents rotation of the fittings when mating hoses are attached with threaded couplings.
In the peristaltic pump of the instant invention, the distance over which the hose is stretched is made variable or adjustable so that a variable rate of flow may be achieved. The flow is varied by an adjuster that pulls the tubing closer or farther away from the center of the rotor. As the distance D from the mounting point increases, hose tension T is increased thereby decreasing leakage QL at the points of roller contact. The relationship between output/input pressure P, tube or hose tension T, fluid viscosity V and tube/hose material choices will determine the pump efficiency. Because of these factors, the pump can run anywhere from zero to 100% volumetric efficiency.
When the spray gun or dispense valve is closed (no material flow) and pump running, leakage volume QL becomes equal to the displacement volume (2Q x rpm) thus preventing overpressurization. The self-compensating pump design eliminates the need for expensive motor speed and/or shutoff controls as well as eliminating high current motor starts (allowing the use of a standard 15 amp outlet).
These and other objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a front perspective view showing the sprayer of the instant invention without a compressor.
Figure 2 is a front perspective view showing the sprayer of the instant invention with a compressor.
Figure 3 is an exploded view showing hose retention mechanism of the sprayer of the instant invention.
Figure 4 is an front perspective view showing hose retention mechanism of the sprayer of the instant invention.
Figure 5 is an side plan view showing hose pressure adjustment mechanism of the sprayer of the instant invention.
Figure 6 is an front plan view showing hose pressure adjustment mechanism of the sprayer of the instant invention.
Figure 7 is an exploded view of the preferred embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

The instant invention, generally designated 10, is a small, relatively inexpensive and self-contained texture sprayer. A cart 12 contains one or more adjustable flow peristaltic pumps 14, a motor 16 (electric or gas), a material supply hopper 18 and a flow control device 20 such as a spray gun or dispense valve. A double-ended motor shaft may be provided wherein one end drive the peristaltic pump 14 and the other end drives an air compressor 22.
As shown in Figure 1, this apparatus may also be provided without the compressor where the user will supply atomization air. A texture spray gun is provided with a small hopper 20a so that it may be used either independently or with the cart mounted material supply. Another version may be provided with a separate compressor having its own motor for independent operation of material and air.
It has been found that the peristaltic pump 14 provides a unique vibration which enhances the flow of high viscosity materials such as texture by loosening the bond between the hose 24 and the high viscosity materials as well as self-cleaning the hopper 18. The pump 14 may be run forward or reverse with reverse being used to empty the hose or transfer material.
The hose retention mechanism 26 on the peristaltic pump 14 consists of a coupled hose 28, a hose retainer plate 30, a mounting plate 32 and a retainer screw 34. A hose with couplings 36 slides onto each end 30a of the hose retainer plate 30. The hose retainer plate 30 is secured to a mounting plate or surface 32 with a fastener 34 while the hose couplings 36 protrude through the surface of the mounting plate 32 for access. The hose retainer plate 30 supports the downward loads imposed by the peristaltic pump 14 while the mounting plate or surface 32 keeps the coupled hose 28 in proper alignment in the pump 14. Matching the profile of the fittings 36 (e.g. hexagon) with the opening 32a of the mounting plate or surface 32 prevents rotation of the fittings 36 when mating hoses 38 are attached with threaded couplings 38a.
In the peristaltic pump 14 of the instant invention, the distance D over which the hose 28 is stretched is made variable or adjustable so that a variable rate of flow may be achieved. The flow is varied by an adjuster 40 that pulls the tubing 28 closer or farther away from the center of the rotor 42 by raising and lowering the mounting plate 32 relative to the frame 12, rotor 42 and rollers 44.
The preferred adjuster 46 is a variable force device for varying the amount of tension on the tubing 28 and the resulting flow. Such device may be a fluid (air or liquid) cylinder which may have, if desired, a separate pressure adjustment 48 for controlling the amount of force applied and accordingly the flow rate. The adjuster 46 may also be a solenoid, adjustable spring or other art recognized force generator.
As the distance D from the mounting point increases, hose tension T is increased thereby decreasing leakage QL at the points of roller 44 contact. The relationship between output/input pressure P, tube or hose tension T, fluid viscosity V and tube/hose material choices will determine the pump efficiency. Because of these factors, the pump can run anywhere from zero to 100% volumetric efficiency.
When the spray gun or dispense valve 20 is closed (no material flow) and pump 14 running, leakage volume QL becomes equal to the displacement volume (2Q x rpm) thus preventing overpressurization. The self-compensating pump design eliminates the need for expensive motor speed and/or shutoff controls as well as eliminating high current motor starts (allowing the use of a standard 15 amp outlet).
It is contemplated that various changes and modifications may be made to the texture sprayer without departing from the invention as defined by the following claims.

Claims

A sprayer (10) for application of viscous materials such as texture, said sprayer (10) comprising:
a frame (12);

a loop of tubing (28) having first and second ends and being attached to said frame (12);

a motor (16), said motor (16) having a shaft with a rotor (42) attached thereto;

a plurality of rollers (44) attached to said rotor (42) and engaging said tubing (28);
characterised by said motor (16) being pivotably attached to said frame (12) to vary the distance between said shaft and said first and second tubing ends; and

a force generator (46) attached between said motor (16) and said frame (12), the force generator (46) being adapted to vary the force with which said rollers (44) contact said tubing (28).
The sprayer (10) for application of viscous materials of claim 1 wherein said force generator (46) comprises an air cylinder.
The sprayer (10) for application of viscous materials of claim 2 wherein said force generator (46) comprises a pressure regulator (48) attached to said air cylinder.
The sprayer (10) for application of viscous materials of claim 1 wherein said tubing (28) is attached at one of said ends to a source of viscous material (18) and at the other of said ends to an application device (20).
The sprayer (10) for application of viscous materials of claim 1 wherein said tubing (28) has couplings (36) at said ends and further comprising a tubing retention mechanism (26) comprising:
a mounting plate (32); and

a hose retainer plate (30), said couplings (36) sliding onto each end of said hose retainer plate (30) with said couplings (36) protruding through the surface of said mounting plate (32) for access and said retainer plate (30) supporting the loads imposed by said rollers (44).
The sprayer (10) for application of viscous materials of claim 5 wherein said couplings (36) comprise a profile and said mounting plate (32) comprises openings (32a) to match said profile of said couplings (36) to prevent rotation of said couplings (36) when tubing (28) is attached.