GB1580658A

GB1580658A - Cleaning apparatus

Info

Publication number: GB1580658A
Application number: GB3010677A
Authority: GB
Original assignee: E Gordon Whiteley Ltd
Current assignee: E Gordon Whiteley Ltd
Priority date: 1977-07-18
Filing date: 1977-07-18
Publication date: 1980-12-03
Also published as: DE2827163A1; FR2397940A1; FR2397940B1; ES471559A1

Description

(54) CLEANING APPARATUS (71) We, E. GORDON WHITELEY LIMITED, of Beech Works, Morley, Leeds, Yorkshire, a British Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : This invention relates to apparatus for cleaning cylindrical printing screens which are used for screen printing on cloth or paper. In use, the screens rotate in contact with a web of cloth or paper traversed beneath them and dyes of different colours are discharged from the screens on to the web in patterns determined by masking of the peripheral surfaces of the screens.

The normal cleaning procedure involves brushing, which requires a great deal of water, does not clean the inside of the screen properly and is liable to damage the screen which has a wall thickness of about 10 thous.

The object of the invention is to provide for ultrasonic cleaning of such a screen by passing successive portions of the screen through a sonified zone. The invention accordingly provides apparatus for cleaning a cylindrical printing screen comprising a tank of sufficient depth to accommodate a screen in a vertical position, means for lowering the screen into the tank and afterwards withdrawing it, a central upstanding pipe in the tank having at its upper end nozzles for spraying cleaning liquid onto the interior of the screen, other nozzles disposed above the level of cleaning liquid in the tank for spraying cleaning liquid onto the exterior of the screen as it emerges from the tank, and an array of ultrasonic transducers disposed peripherally around the upper end of the tank for creating an ultrasonic field in the liquid contained in the tank.

One embodiment of ultrasonic screen cleaning apparatus according to the invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: Figure l is a diagrammatic side elevation, partly in section; Figure 2 is a sectional view, on a larger scale, of the upper part of the cleaner shown in Figure 1; Figure 3 is a similar view of the lower part of the cleaner; Figure 4 is a section on the line IV-IV in Figure 2; and Figure 5 is a section on the line V-V in Figure 3.

The cleaning apparatus shown in the drawings includes a tank 10 of sufficient depth to receive a screen 11 to be cleaned in a vertical position. The screen 11 is supported in an open cage 12, which is lowered by an electrically operated winch 13 (Figure 1) so as to introduce the screen gradually into the tank 10. The ends of the screen 11 are located in the cage 12 by walls 14 on the cage as shown in Figures 2, 3 and 5. As indicated in Figure 5, the cage consists of two parts hinged together by a hinge pin 15 and a suitable fastener 16 is provided to hold the hinged parts in the closed position.

The tank 10 contains a central upstanding pipe 16, having nozzles 17 at its upper end for spraying water on to the interior of the screen 11. The lower end of the pipe 16 is connected by a pipe 18 to a water supply pipe 19. An array of ultrasonic transducers 20 disposed peripherally around the upper end of the tank 10 creates an ultrasonic field in the water contained in the tank through which successive zones of the screen 11 pass as it is lowered into the tank. Energy is supplied to the transducers 20 by equipment contained in a cabinet 21.

Above the water level L in the tank 10 are annular water spray pipes 22, connected to the water supply pipe 19 and supported by wires 23 which extend upwardly from the tank. The pipes 22 spray water on to the exterior of the screen 11 as it is withdrawn from the tank 10 by the winch 13. Above the water spray pipes 22 is an annular air jet pipe 24, connected by a pipe 25 to an air inlet pipe 26. The pipe 24 directs air against the outer surface of the emerging screen 11 to remove excess water. A drain pipe 27 is provided at the bottom of the tank 10 for removing the dirty water. A pivotally mounted tray 28 is provided for loading the screen 11 into the cage 12 and for receiving the unloaded screen after cleaning.

The above described apparatus is suitable for cleaning screens which have been used to print water-based inks. In the case of screens printing solvent-based inks the tank will contain the appropriate solvent instead of water and a solvent recovery plant is provided, together with a pump for feeding recovered solvent to the internal and external sprays.

WHAT WE CLAIM IS: 1. Apparatus for cleaning a cylindrical printing screen comprising a tank of sufficient depth to accommodate a screen in a vertical position, means for lowering the screen into the tank and afterwards withdrawing it, a central upstanding pipe in the tank having at its upper end nozzles for spraying cleaning liquid onto the interior of the screen, other nozzles disposed above the level of cleaning liquid in the tank for spraying cleaning liquid onto the exterior of the screen as it emerges from the tank, and an array of ultrasonic transducers disposed peripherally around the upper end of the tank for creating an ultrasonic field in the liquid contained in the tank.

2. Apparatus according to claim 1, which includes air jets disposed above said other nozzles for directing air against the outer surface of the emerging screen to remove excess cleaning liquid.

3. Apparatus according to claim 1 or claim 2, in which the lowering means includes a winch disposed above the tank and an open cage, supported from the winch, for supporting the screen as it is lowered into and withdrawn from the tank by the winch.

4. Apparatus according to claim 1, substantially as described herein with reference to the accompanying drawings. ~~~

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. wires 23 which extend upwardly from the tank. The pipes 22 spray water on to the exterior of the screen 11 as it is withdrawn from the tank 10 by the winch 13. Above the water spray pipes 22 is an annular air jet pipe 24, connected by a pipe 25 to an air inlet pipe 26. The pipe 24 directs air against the outer surface of the emerging screen 11 to remove excess water. A drain pipe 27 is provided at the bottom of the tank 10 for removing the dirty water. A pivotally mounted tray 28 is provided for loading the screen 11 into the cage 12 and for receiving the unloaded screen after cleaning. The above described apparatus is suitable for cleaning screens which have been used to print water-based inks. In the case of screens printing solvent-based inks the tank will contain the appropriate solvent instead of water and a solvent recovery plant is provided, together with a pump for feeding recovered solvent to the internal and external sprays. WHAT WE CLAIM IS:

1. Apparatus for cleaning a cylindrical printing screen comprising a tank of sufficient depth to accommodate a screen in a vertical position, means for lowering the screen into the tank and afterwards withdrawing it, a central upstanding pipe in the tank having at its upper end nozzles for spraying cleaning liquid onto the interior of the screen, other nozzles disposed above the level of cleaning liquid in the tank for spraying cleaning liquid onto the exterior of the screen as it emerges from the tank, and an array of ultrasonic transducers disposed peripherally around the upper end of the tank for creating an ultrasonic field in the liquid contained in the tank.