GB2349183A

GB2349183A - Multi-component mixing and dispensing pumping system with pump reversal

Info

Publication number: GB2349183A
Application number: GB0005916A
Authority: GB
Inventors: Patrick Sumner
Original assignee: RSG SYSTEMS Ltd
Current assignee: RSG SYSTEMS Ltd
Priority date: 1999-03-13
Filing date: 2000-03-10
Publication date: 2000-10-25
Also published as: GB9905677D0; GB0005916D0

Abstract

A pumping system for mixing and dispensing a two part resin comprises reservoirs 5,6 and associated gear pumps, driven by a common DC motor via gear wheels 2,3,4, which pump the two components of resin to a static mixer 7 and out through a nozzle 8. The pumps are reversed after stopping, to suck back excess resin at nozzle 8, preventing dripping. The system can be used in association with a computer controlled plotter arm to apply resin to glass sheets to simulate lead in leaded lights and stained glass windows.

Description

Pump The present invention relates to a precision pumping system which gives accurate and precise control with viscous liquids.

When resins are attached to glass sheets to form decorative panels, the resin is applied by means of a pump which pumps the resin out from a reservoir onto the glass sheet where the resin hardens and adheres to the sheet. When the resin is formed of two or more components which react together to cause the resin to set hard the components are preferably mixed just before they are applied to the surface. In forming decorative panels which simulate the appearance of leaded lights and stained glass panels the resin simulates the appearance of the lead and after is applied and has hardened the separate panels can be coloured to give the desired effect.

In order to obtain reproducible effects accurate application of the resin is essential and there must be no over run or deviation.

In one process the design is fed into a computer which controls a plotter and the plotter applies the resin to a glass panel in accordance with a programme. In this way any design can be reproduced as required. It is also possible to scan a drawing, design or picture into the computer and the plotter will then reproduce an outline of the picture in resin on a glass panel.

When a two part resin is applied to the glass panel the components are mixed and the resin applied via a pump to the panel, however due to the viscous nature of the resin and the relatively small volumes of resin being applied it has proved difficult to achieve the necessary accuracy and precision and to maintain"clean"lines.

We have now devised an improved pump which reduces these difficulties.

According to the invention there is provided a pumping system for supplying a resin formed from a plurality of components which pumping system comprises a plurality of reservoirs each of which is adapted to contain a separate component of the resin with each reservoir being associated with a reversible pump, the pumps being driven from a single motor and able to pump a component from each reservoir to a mixing means where the components can be mixed together, there being an exit means from the mixing means through which the mixed components can be pumped, the pumps being able to be reversed to prevent leakage of the resin.

The pumps can be reversed in response to the operation of a switch which can be manually or automatically operated.

The pumps can be operated from one motor so that the relative rate of pumping by each motor is precisely controlled so that the components are mixed together in the exact ratio to form the resin. When the pumps are reversed there is preferably a suction effect applied to the mixing means so that the resin in the mixing means is withdrawn from the exit means.

The mixing means can be any suitable mixer for example a long static mixer which ensures adequate mixing. The pumps are preferably hydraulic gear pumps so the drive gears can be driven from a common motor. The motor can be any suitable motor e. g. a DC motor or a stepper motor.

The pumping system is particularly suitable for pumping small volumes e. g. less than 0.5 mls. of viscous resin components without any spillage or drips.

In one embodiment of the invention the pump is attached to the arm of a plotter and the motor is controlled by the computer which controls the plotter. The resin components are mixed together and pumped out in accordance with a programme so that the movement of the plotter and the application of the mixed resin is precisely controlled to give the required design or outline. When there is to be a gap in the application of the resin the motor reverses in accordance with the programme controlling the plotter and causes suction to be applied to the resin to prevent drips.

The plotter arm can then move to a different location, the motor engaged and pumping recommenced. At the completion of the design the motor is reversed and the application of the resin stopped. This enables the resin to be precisely applied to a panel in accordance with the programmed plotter with no risk of any imprecision or wastage of resin.

In another embodiment of the invention the operation of the pumps can be controlled by means of a manually operated switch e. g. located on the mixing means, which can be for example a static mixer. By having flexible hoses from the pumps to the mixer the mixer can move or be moved without necessarily having to move the pump, and so can be used under the personal control of a user to produce a desired design in resin on a panel, without the design having to programmed into a computer.

The invention is described in the accompanying drawing which illustrates schematically an embodiment of the invention.

In the drawing a housing (1), which is attached to a plotter arm (not shown), contains a DC motor driving gear wheel (2). Gear wheels (3) and (4), which are identical to each other and to wheel (2), mesh with (2) and are driven thereby. There are reservoirs (5) and (6) each of which contain a component of a two part resin which are to be mixed in equal volumes to form the resin. There is an hydraulic pump (not shown) driven by wheel (3) which can pump liquid from (5) and a similar pump driven by (4) which can pump liquid from (6). The liquids from (5) and (6) can be pumped to long static mixer (7) where they can be mixed and the mixed resin pumped out of exit nozzle (8) and then applied to a glass panel.

The movement of the plotter arm over the glass panel and the operation of the pumps is controlled by a pre-programmed computer.

In use the plotter arm moves to the location where the resin is to be applied and the motor started to drive the wheel (2) which drives the wheels (3) and (4) and so pump the liquids into the mixer (7) where they are mixed. As the pumps are driven at the same speed the liquids from each reservoir are mixed in equal portions. At the exact pre-programmed location the resin commences to be pumped out of exit (8) at a precisely controlled flow rate which is maintained by the speed of rotation of the pumps in accordance with the instructions from the computer. The plotter arm moves over the glass panel to form a design in the resin on the panel and the resin then hardens and sticks to the panel. When the flow of resin is to be stopped, either so there is a gap in the design or when the process is completed, the computer instructs the motor driving wheel (2) to reverse which causes the pumps to reverse and apply suction at exit (8) which stops the flow of resin at the precise location required without any dripping. The plotter arm can then be moved over the panel without the risk of resin being dripped in an unwanted position.

Claims

Claims 1. A pumping system for supplying a resin formed from a plurality of components which pumping system comprises a plurality of reservoirs each of which is adapted to contain a separate component of the resin with each reservoir being associated with a reversible pump, the pumps being driven from a single motor and able to pump a component from each reservoir to a mixing means where the components can be mixed together, there being an exit means from the mixing means through which the mixed components can be pumped, and there being means to reverse the pumps to prevent leakage of the resin.
2. A pumping system as claimed in claim 1 in which the pumps are reversed in response to the operation of a switch is automatically operated.
3. A pumping system as claimed in claim I or 2 in which the pumps are operated from one motor and the relative rate of pumping by each motor is precisely controlled so that the components are mixed together in the exact ratio to form the resin.
4. A pumping system as claimed in any one of claims 1 to 3 in which, when the pumps are reversed there is a suction effect applied to the mixing means so that the resin in the mixing means is withdrawn from the exit means.
5. A pumping system as claimed in any one of claims 1 or 4 in which the pumps are hydraulic gear pumps driven from a common motor.
6. A pumping system as claimed in any one of claims I to 5 in which the mixing means is a long static mixer.
7. A pumping system as claimed in any one of the preceding claims in which the mixing means is attached to the arm of a plotter.
8. A pumping system as claimed in claim 7 in which the pump is attached to the arm of a computer controlled plotter and the motor and the means to reverse the pump are controlled by the said computer.
9. A pumping system as claimed in claim 7 in which the mixing means is attached to the arm of a plotter and the pumps are connected to the mixing means by flexible hoses from the pumps to the mixer so the mixer can move or be moved without having to move the pump.
10. A method of supplying a resin formed from a plurality of components which comprises using a reversible pump to pump the components from separate reservoirs to a mixing means where the components are mixed together and pumping the mixed components through an exit and when the pumping is completed reversing the pumps to provide suction at the exit means to prevent leakage of the resin.
11. A method as claimed in claim 10 in which the mixing means is attached to the arm of a computer controlled plotter and the resin components are mixed together and pumped out in accordance with a programme installed in the computer so that the movement of the plotter and the application of the mixed resin is controlled and when there is a gap in the application of the resin the motor reverses in accordance with the programme controlling the plotter which causes suction to be applied to the resin to prevent drips from the exit.
12. A method as claimed in claim 10 in which the mixing means is attached to the arm of a plotter and the reversing means is controlled by a manually operated switch.
13. A pumping system as hereinbefore described with reference to the drawings.