GB2150518A

GB2150518A - Pneumatic tube conveyor system

Info

Publication number: GB2150518A
Application number: GB08331969A
Authority: GB
Inventors: James Arthur Noon
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-11-30
Filing date: 1983-11-30
Publication date: 1985-07-03
Also published as: GB8331969D0

Abstract

A pneumatic tube conveyor system has an inlet tube and an outlet tube with a pneumatic drive device therebetween, such that the inlet and outlet tubes are open to the atmosphere and articles can pass through the pneumatic drive device from the inlet to the outlet. The drive device has axially aligned inlet and outlet tube portions (7 and 11), the inlet tube portion (7) extending through a suction chamber and opening into a pressure chamber, and having suction apertures in the wall thereof within the suction chamber. The outlet tube portion (11) extends through the pressure chamber and ends in an outwardly flared portion adjacent to the end of the inlet tube portion (7) so as to create around the junction between the two tubes a reduced pressure which draws the articles from the inlet tube portion to the outlet tube portion, from which they are pushed by the elevated pressure. <IMAGE>

Description

SPECIFICATION Pneumatic tube conveyor system This invention relates to a pneumatic tube conveyor system suitable for conveying a range of different sized articles and particulate material.

Conventional pneumatic tube conveyor systems, for example for conveying containers for cash and documents, require a sealed pressure chamber at each end of the conveyor tube, each chamber being connectable to a source of pressure and, alternatively, to a vacuum source when the container has been introduced into the tube so as to drive the container along the tube. The container therefore requires annular seals to ensure that it is a sealing fit within the tube. The pressure chambers, since they need to be opened regularly, can give rise to pressure losses which reduce the efficiency of the system.In addition, either pressure and vacuum sources have to be located near to each pressure chamber, with consequent increase in the cost and noise, as well as space occupied, or pipes have to be run to the chambers from a central air blower and the additional piping required occupies further space and adds to the cost of installation of the system. This type of conveyor cannot readily transport particulate materials, except where they are placed within individual containers.

According to the present invention, a pneumatic tube conveyor system has an inlet tube, an outlet tube, and a pneumatic drive device therebetween, the inlet and outlet tubes being open to the atmosphere, and the pnuematic drive device being arranged to draw articles to be conveyed into the inlet tube and to drive the articles through the system in a continuous movement to be expelled from the outlet tube.

Preferably, the drive device comprises inlet and outlet tube portions aligned on a common axis, the inlet tube portion extending through a suction chamber connected to suction means, the open end of the inlet tube portion opening into a pressure chamber connected to a pressure source, the inlet tube portion having through the wall thereof within the suction chamber at least one aperture whereby air may be drawn from within the tube, the outlet tube portion extending through the pressure chamber with the open end thereof adjacent to the open end of the inlet tube portion, the annular space between the two adjacent open ends being adapted to direct air flowing from the pressure chamber through the annular space into the outlet tube portion and away from the inlet tube portion whereby a depression is created with draws air from the inlet tube.Thus, articles are drawn into the drive device and pass through a transition zone from the suction side of the device to the blowing side of the device wherein the articles are pushed along by a pressure in excess of atmospheric pressure.

A plurality of apertures may be provided in the wall of the inlet tube portion, preferably split into two sets, one set being remote from the pressure chamber and the other set being adjacent thereto.

Preferably the sets of apertures are dimensioned such that the air flow through the set remote from the pressure chamber is greater than that through the set adjacent to the pressure chamber.

The suction means and the pressure source may be the inlet and outlet of a single fan or blower, and control of the delivery speed of the articles may be effected by controlling the air pressure delivered to the pressure chamber, for example by bleeding off some of the air to slow the delivery speed.

For conveying articles over a long distance, a plurality of the pneumatic drive devices may be connected in series, so as to be used as repeaters along the length of a pipe line. This has the advantage that the pressure or suction at any point in the pipe line is kept within reasonable limits, thereby ensuring that the speed of the articles along the pipe line is kept more uniform.

The system of the invention can be used for conveying a wide variety of articles, for example plastic cups, containers for documents or cash, plastics beads, or even grain. One advantage of the system is that the delivery speed can be carefully controlled, thus minimising the risk of damage to the articles at the delivery outlet of the tube. Greater flexibility of installation is gained.

For conveying containers for documents or cash, seals are not required, and containers made be made very light, for example of plastics material, but use of seals, e.g. of felt, will increase the speed of delivery and may increase the overall efficiency of the system.

Reference is made to the drawings, in which: Figure 1 is a perpesctive view, partially cut away, of a preferred pneumatic drive device for use in the system of the invention; Figure 2 is a perspective view of a conveyor system in accordance with an embodiment of the invention; and Figure 3 is an elevation of a conveyor system in accordance with another embodiment of the invention.

Referring first to Figure 1. the drive device comprises an outer cylindrical casing 1, divided by an internal annular wall, 2 into a suction chamber 3 and a pressure chamber 4, the suction chamber 3 having a connector 5 whereby the chamber may be connected to a suction pump or fan (not shown) and the pressure chamber 4 has a connection 6 whereby it may be connected to a pressure source such as a fan outlet.

An inlet conveyor tube portion 7 extends through the end wall 8 of the suction chamber 3 and through the internal annular wall 2, to which it is sealed. The inlet tube portion 7 has within the suction chamber 3 two sets of apertures in the wall thereof whereby air may be drawn from the inlet tube into the suction chamber. The first set of apertures 9 is positioned at a distance of approximately 1.3D from the end of the tube 7 which opens into the pressure chamber 4, i.e. all the apertures in the first set 9 are more than 1.3D from the end of the tube, D being the internal diameter of the inlet tube. The apertures in the first set 9 have a total area approximately twice that of the total area of the apertures in the second set 10, which is adjacent to the pressure chamber and spaced by a distance of approximately 0.3D from the end of the inlet tube.

An outlet conveyor tube portion 11 extends through the end wall 12 of the pressure chamber 4 with its longitudinal axis coincident with that of the inlet conveyor tube portion 7. The end of the portion 11 within the chamber 4 is flared outwardly and is spaced from the end of the inlet tube portion 7 by a distance equivalent to 0.1D taken from the transition between the straight tube and the flared portion. The flared portion is so shaped and positioned relative to the end of the inlet tube portion 7 that pressurised air in the pressure chamber 4 enters the outlet tube portion 11 in a direction away from the inlet tube portion and along the outlet tube portion 11. By a venturi effect, the pressure of the gases around the end of the inlet tube portion is reduced, thus drawing air from the inlet tube portion and into the outlet tube portion.This ensures that there is a continuity of flow of articles from the inlet tube portion to the outlet tube portion.

By varying the sizes of the suction and pressure chambers 3 and 4 relative to the tube portions 7 and 11, and by varying the numbers and positions of the inlet apertures in the sets 9 and 10, the performance of the drive device can be varied, in particular the speed of articles through the device and the efficiency of conveying.

It will be observed that the flaring of the end of the outlet tube portion 11 not only has the effect of guiding the air in the desired direction, but also ensures that any large articles conveyed along the tube portions 7 and 11 do not become caught on any sharp edges at the transition from one tube portion to the other.

Referring now to Figure 2, a conveying system for delivering plastics mouldings, such as screw tops for glass jars, comprises a tapered hopper 20 delivering the mouldings into an inlet tube 21 which is in turn connected to the inlet conveyor tube portion 7 of a device as described hereinbefore with reference to Figure 1. The device 22 has connected thereto a suction pipe 23 and a pressure pipe 24 connected to an electrically powered blower 25 in such a manner that air is drawn into the blower along the pipe 23 and returned to the device 22 via pipe 24. An adjustable delivery tube 26 is connected to the outlet conveyor tube portion 11 of the device 22. The delivery pipe 26 is suitably arranged to deliver the mouldings to the upper part of, for example, a machine arranged to apply the lids to filled jars.

The whole conveyor system is mounted on a frame 27 provided with castors 28 so that the conveyor system may readily be moved.

Figure 3 shows a conveyor system used for delivering plastics cups from a production line to a collector which stacks the cups for packaging. The cups 30 are delivered from the production line on a continuous conveyor belt 31 which passes under the inlet pipe 32 of the conveyor system. The inlet pipe 32 is connected to the inlet conveyor tube portion 7 of a device 22 as illustrated in, and as hereinbefore described with reference to, Figure 1.

Again, the suction and pressure chambers 3 and 4 are connected to opposite sides of an electrically driven fan 25, shown schematically, while the outlet conveyor tube portion 11 of the device 22 is connected to a delivery tube 33. The delivery tube 33 is connected in turn to the upper end of a cup collector 34 in which the cups are stacked until the stack reaches the desired height for packaging, when it is removed from the collector.

The drive device 22 may be positioned at any convenient location clear of the production line and packaging location, these two being separated by a large distance if desired. The pipes 32 and 33 can be run, for example, near to the roof of the factory and the drive device, since it takes only a relatively small space, can also be mounted adjacent the roof of the factory to allow clearance beneath for other equipment, for example.

Since the delivery speed of the cups can be readily adjusted, for example by adjusting the air pressure delivered to the pressure chamber, the likelihood of damage to the cups or jamming together of the cups will be greatly reduced.

Claims

1. A pneumatic tube conveyor system having an inlet tube, an outlet tube, and a pnuematic drive device therebetween, the inlet and outlet tubes being open to the atmosphere, and the pnuematic drive device being arranged to draw articles to be conveyed into the inlet and to drive the articles through the system in a continuous movement to be expelled from the outlet tube

2.A system according to Claim 1, wherein the drive device comprises inlet and outlet tube portions aligned on a common axis, the inlet tube portion extending through a suction chamber connected to suction means, the open end of the inlet tube portion opening into a pressure chamber connected to a pressure source, the inlet tube portion having through the wall thereof within the suction chamber at least one aperture whereby air may be drawn from within the inlet tube, the outlet tube portion extending through the pressure chamber with the open end thereof adjacent to the open end of the inlet tube portion, the annular space between the two adjacent open ends being adapted to direct air flowing from the pressure chamber through the annular space into the outlet tube portion and away from the inlet tube portion, whereby a depression is created which draws air from the inlet tube portion.

3. A system according to Claim 2, wherein two apertures or sets of apertures are provided in the wall of the inlet tube portion, one aperture or set of apertures being remote from the pressure chamber and the other aperture or set of apertures being adjacent to the pressure chamber.

4. A system according to Claim 3, wherein the aperture or set of apertures remote from the pressure chamber has a greater area than the aperture or apertures adjacent to the pressure chamber.

5. A system according to Claim 3 or 4, wherein the aperture or set of apertures adjacent to the pressure chamber is spaced from the end of the inlet tube by a distance approximately equivalent to 0.3D, where D is the internal diameter of the inlet tube portion.

6. A system according to Claim 3, 4 or 5, where in the aperture or set of apertures remote from the pressure chamber is spaced from the end of the inlet tube by more than 1.3D, where D is the internal diameter of the inlet tube prtion.

7. A system according to any of Claims 2 to 4, wherein the apertures are covered by a fine mesh whereby small particles conveyed by the system are retained within the tube.

8. A system according to any of Claims 2 to 7, wherein the inlet tube projects slightly into the pressure chamber.

9. A system according to any of Claims 2 to 8, wherein the end of the outlet tube is flared outwardly.

10. A system according to Claim 9, wherein the the transition between the straight part of the outlet tube portion and the flared portion is set at a distance of approximately 0.1D, wherein D is the internal diameter of the inlet tube portion, from the end of the inlet tube portion.

11. A system according to any of Claims 2 to 10, wherein the suction means is a fan or blower.

12. A system according to Claim 11, wherein the pressure source is the outlet from the fan or blower.

13. A system according to any of Claims 2 to 12, wherein pressure control means are provided for varying the pressure delivered by the pressure source whereby the delivery speed of articles can be controlled.

14. A system according to Claim 13, wherein the pressure control means comprise a bleed valve in the supply line from the pressure source to the pressure chamber.

15. A system according to any preceding claim, wherein the inlet tube is connected to the base of a supply hopper for articles.

16. A system according to any preceding claim, comprising a plurality of pneumatic drive devices spaced along a conveyor tube between the inlet tube and the outlet tube.

17. A pneumatic tube conveyor system, comprising a pnuematic drive device substantially as described with reference to, or as shown in, Figure 1 of the drawings.

18. A pneumatic tube conveyor system, substantially as described herein with reference to, or as shown in, Figure 2 or Figure 3 of the drawings.