GB2143787A

GB2143787A - Pneumatic conveying system

Info

Publication number: GB2143787A
Application number: GB08319088A
Authority: GB
Inventors: Jeffery James Rainer
Original assignee: LAMSON D D PLC
Current assignee: LAMSON D D PLC
Priority date: 1983-07-14
Filing date: 1983-07-14
Publication date: 1985-02-20
Also published as: IT8421841A1; GB2143787B; IT1196186B; IT8421841A0; GB8319088D0

Abstract

In a pneumatic conveying system, for a hospital, bags of soiled laundry and of refuse are conveyed from inlet stations (6 and 7) on different floors through laundry chutes (1) and refuse chutes (2) and a conveying pipe (5) to their respective destinations; a laundry bag collector (3) and an incinerator (41). The conveying pipe (5) is common to both kinds of bags and includes a diverter (25) enclosed within the laundry bag collector (3) which either directs laundry bags out of the pipe (5) and into the collector (3) or allows refuse bags to pass through the laundry bag collector (3) along the pipe (5) to the incinerator (41). <IMAGE>

Description

SPECIFICATION Pneumatic conveying system This invention relates to a pneumatic conveying system for moving goods of different kinds from a number of collecting points and delivering them to various destinations. One example is a conveying system for a hospital in which bags of laundry and of refuse are taken from different buildings and/or different floors of a building or buildings and delivered respectively to a laundry and incinerator (or other waste disposal means).

Particularly in large installations costs are reduced if there is a conveying pipe common to both or all the kinds of goods for the main part of the system. The different kinds of goods must then be dealt with one kind at a time and means is required for separating one kind from another and delivering them to the right destination.

It is an object of the present invention to provide such a system and in particular means for separating different kinds of goods for delivery to the ap propiiate destination.

The present invention consists in a pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations comprising a conveying pipe common to the different kinds of goods wherein is provided sorting means enclosed within a chamber and movable between first and second positions, the sorting means in the first position affording continuity of the conveying pipe through the chamber and in the second position directing goods out of the conveying pipe into the chamber.

The system of the present invention is less expensive to install and simpler to operate than previously known installations in which switch valves and branch pipes are provided for directing selectively different kinds of goods to various destinations because, in the present invention, segregation of the different kinds of goods is achieved within a chamber which constitutes the destination for one kind of goods.

The chamber needs to be sealed to the extent necessary to maintain sufficient sub-atmospheric pressure within the conveying pipe for the conveyance of goods but the sorting means itself does not need to seal the pipe from the chamber in its first position. A door or doors may be provided for the removal from time to time of goods collected in the chamber.

The conveying system may include more than one sorting means and associated chamber, the conveying pipe passing through each of the chambers. The additional sorting means may be provided for dealing with more than two kinds of goods or for enabling any one of the kinds of goods to be delivered to different destinations.

The sorting means may be a diverter, mounted for angular movement about its junction with the upstream side of the conveying pipe such that in the first position its other end is aligned with the entry to the downstream side of the conveying pipe and in the second position is out of alignment therewith and directed into the chamber. It is preferred that the diverter is a full-section of tube to ensure that goods intended to continue into the downstream side of the conveying pipe are not accidentally dislodged so as to fall into the chamber.

The diverter tube may be joined to the upstream side of the conveying pipe by a flexible joint such as a bellows section.

Although it is not generally necessary for the sorting means to seal the pipe from the chamber in its first position, sealing means may be provided for sealing the diverter tube to the downstream side of the conveying pipe when the diverter tube is in its first position. Such a provision would allow removal of goods from the chamber while the diverter tube is in the first position and goods are being conveyed along the conveying pipe to a destination downstream of the chamber.

Control means operable from outside the chamber is preferably provided for moving the sorting means. The control means may be merely a mechanical, manually-operated device but is preferably power-operated, for example by a fluidpressure cylinder or by an electric motor or other electrically energised device.

Atmospheric pressure on the outside of a single door or set of doors from the chamber would normally prevent their being opened while sub-atmospheric pressure existed within the chamber, Goods could not normally then be removed from the chamber until it had been relieved of sub-atmospheric pressure, for example, between evacuation or conveying cycles. Alternatively means may be provided for isolating the chamber from the remainder of the conveying pipe and the sub-atmospheric pressure existing therein and a by-pass tube be provided around the chamber to transfer subatmospheric pressure between the separated parts of the conveying pipe. As a further option a pressure lock may be provided to afford access to the chamber while still at sub-atmospheric pressure.

Such a pressure lock may comprise a vestibule with inner and outer doors, the inner door opening to the chamber.

By opening the inner door goods may be transferred from the chamber to the vestibule and the inner door closed. Air is then admitted to the vestibule to allow its pressure to rise after which the outer door can be opened and the goods removed.

Chutes may be provided to receive goods from collecting points on floors of a multi-storey building, or branch pipes may serve collecting points in different parts of a building, for example isolated or distant parts of a building. The chutes and branch pipes are connected to the main conveying pipe and isolating valves may be provided for isolating any of the chutes or branch pipes from the main conveying pipe, for use particularly during evacuation or conveying cycles, for example, so that some of the collecting points may still be available to receive goods. Chutes or branch pipes may serve a number of collecting points for one of the kinds of goods or may be common to collecting points for different kinds of goods.

Detection means may be provided at the collect ing points for detecting insertion of the wrong kind of goods for that collecting point.

The collecting points may include inlet stations at which goods of any one of the different kinds of goods may be assembled, prior to release into or towards the conveying pipe. Each inlet station may comprise an outer door forming an entry for goods into the system, an inner door leading into or towards the conveying pipe and a storage space between the outer and inner doors. The outer door may be lockable when the inner door is to be opened to release assembled goods into or towards the conveying pipe.

With the provision of inlet stations on chutes connected to the main conveying pipe it is not necessary for the chutes themselves to serve as collecting spaces for the goods prior to their release into the main conveying pipe.

The whole or parts of the pneumatic conveying system may be under programmer control governing, for example, the locking of entry doors at the collecting points, assessment of the need for evacuation or conveying cycles, determination of the kind of goods to be dealt with in an individual evacuation or conveying cycle and the appropriate actuation of the sorting means, determination of the sequence in which goods are removed from the various collecting points or chutes or branch pipes, detection of the readiness of apparatus at the destinations to deal with the goods, the starting and stopping of exhausters or suction pumps for producing the sub-atmospheric pressure and the opening and closing of the necessary valves at each stage of the programme.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic representation of a pneumatic system for conveying bags of laundry and bags of refuse respectively to a laundry bag collector and to a refuse bag collector; Figure 2 is an enlarged view of one type of inlet station on one of the chutes; and Figure 3 is an enlarged view of an alternative type of inlet station on another of the chutes.

The pneumatic system comprises a plurality of laundry chutes 1, a plurality of refuse chutes 2, a laundry bag collector 3, a refuse bag collector 4, a conveying pipe 5, and a high-vacuum exhauster system.

The system is arranged to convey bags of laundry and bags of refuse respectively from the laundry and refuse chutes 1 and 2 to the laundry and refuse bag collectors 3, 4 along the conveying pipe 5 during an "evacuation cycle" under the control of a programmer (not shown).

The laundry and refuse chutes 1 and 2 are arranged to extend substantially vertically passing through a plurality of levels of the building in which the system is installed, for example, a hospital, hotel, office block or the like. On each level of the building each laundry chute 1 has an inlet station 6 through which bags of laundry may be introduced into the chute 1. Similarly, on each level, each refuse chute 2 has an inlet station 7 through which bags of refuse may be introduced into the chute 2.

The inlet stations 6 and 7 constitute collecting points respectively for the laundry bags and for the refuse bags and each inlet station 6, 7 comprises a lockable outer door 8, 9, a normally closed inner door 10, 11 and a storage space 12, 13 between the outer and inner doors 8 and 10, 9 and 11.

Figures 2 and 3 respectively show two different types of inlet stations 6 and 7 which differ only in the arrangement of the outer doors 8 and 9. In Figure 2 the outer door 8 is spaced from the wall 50 next to the chute 1 and is hinged about an axis that is slightly inclined to the horizontal so that the door 8 opens upwardly into the position indicated by broken lines, whereas in Figure 3 the outer door 9 is set into the wall 51 next to the chute 2 and is hinged about a vertical axis so that the door 9 opens outwardly from the wall 51 into the position indicated by broken lines.When laundry and refuse bags are introduced through the outer door 8, 9 of each inlet station 6, 7 they fall down into the respective storage space 12, 13 where they come to rest either upon the inner door 10,11 of that inlet station 6, 7 or upon other bags already in the storage space 12, 13.

Each inner door 10, 11 as shown in Figures 2 and 3 comprises a wire mesh framework which, in the closed position shown in the drawings, prevents laundry or refuse bags in the storage space 12, 13 from passing into the associated chute. The inner door 10, 11 is normally held in this closed position by an electrically operable latch 16, 17 which is under the control of the programmer.

When the latch 16, 17 is released by the programmer, the inner door 10 , 11 is allowed to swing through an angle of approximately 75 into the open position indicated by broken lines. When the inner door 10, 11 occupies this open position laundry or refuse bags are allowed to fall from the storage space 12, 13 into the associated laundry or refuse chute 1, 2.

In the system shown in Figure 1, the inlet stations 7 of the refuse chutes 2 are of the type shown in Figure 3 in which the outer doors 9 are hinged about a vertical axis, whereas the inlet stations 6 of the laundry chutes 1 are of the type shown in Figure 2 in which the outer doors 8 are hinged about an axis slightly inclined from the horizontal.

However, it will be appreciated that the refuse chutes may have inlet stations of the type shown in Figure 2 and that the laundry chutes may have inlet stations of the type shown in Figure 3. The type of inlet station 6 or 7 used for a particular chute is normally determined by the space available on each side of the wall 50, 51 next to that chute.

Each inlet station 6, 7 also includes detection means associated with the outer door 8, 9 of that inlet station for detecting whether a bag introduced through the outer door 8, 9 is either a laundry bag or a refuse bag. The detection means associated with each outer door 8, 9 may comprise any convenient form of electrical detection device which is arranged to produce an electrical signal indicative of the type of bag introduced through the outer door 8, 9. Identifying means may be provided on the bags to actuate the detection means.

Preferably only one type of bag may be provided with identifying means and the detection means may be actuated by the presence and absence respectively of identifying means on a bag.

The identifying means may comprise a tracer printed on one type of bag and the detection means may comprise a "reader" which is arranged to produce an electrical signal when it detects a tracer in the storage space.

Alternatively, the laundry bags and refuse bags may react in a different manner to ultra-violet light in which case ultra-violet detection means may be provided.

The outer doors 8, 9 of the inlet stations 6, 7 are individually lockable under the control of the programmer and the inner doors 10, 11 are normally held in their closed positions by the latches 16, 17 which are individually controllable by the programmer, each inner door 10, 11 only being allowed to open during an evacuation cycle when its associated latch 16, 17 is released by the programmer.

When the detection means associated with an outer door 8, 9 of an inlet station 6, 7 produces an electrical signal which indicates that the wrong type of bag has been introduced into that inlet station 6, 7, the associated latch 16, 17 is locked in response to that signal to prevent the inner door 10, 11 of that inlet station from opening.

In this manner the detection means of each refuse bag compartment 13 prevents laundry bags from being introduced into the refuse chutes 2 and the detection means of each laundry storage space 12 prevents refuse bags from being introduced into the laundry chutes 1.

The detection means associated with an outer door 8 of an inlet station 6 of a laundry chute 1 is also arranged to produce an alarm signal when it detects a refuse bag introduced into that inlet station 6. Similarly, the detection means associated with an outer door 9 of an inlet station 7 of a refuse chute 2 is arranged to produce an alarm signal when it detects a laundry bag introduced into that inlet station 7.

The alarm signal may be a visible signal such as a warning light on the outer door. Alternatively, or additionally, the alarm signal may be an audible warning signal.

There is associated with the storage space 12, 13 of each inlet station 6, 7 sensing means for sensing that the storage space 12, 13 is full and can receive no more bags.

Each sensing means comprises a sensor which produces an electrical signal which indicates whether or not the associated storage space 12, 13 is full. Each sensor preferably comprises a photoelectric cell. The programmer is responsive to the signals from the sensors and is arranged to initiate an evacuation cycle when one storage space is full or a specified number of storage spaces 12, 13 are full.

A normally-closed pneumatically operable chute isolating valve 14, is disposed in each chute 1, 2 towards the lower end of the chute 1, 2.

The upper ends of the chutes 1 and 2 are provided respectively with air inlets 18 and 19. Each air inlet 18, 19 is restriction of the full bore of the chute.

The chutes 1, 2 are all connected below their chute isolating valves 14, 15 to the conveying pipe 5 which leads from the chutes 1, 2 to the laundry bag collector 3 and to the refuse bag collector 4.

From the lower ends of the chutes 1,2 the conveying pipe passes in through one side of the laundry bag collector 3 and out through another side of the collector 3. The conveying pipe 5 then leads from the laundry bag collector 3 into the refuse bag collector 4 where it terminates in an open end section 20 inside the refuse bag collector 4. An isolating valve 21 is disposed in the conveying pipe towards the open end section 20.

Sorting means enclosed within the laundry bag collector 3 is provided for directing laundry bags from the conveying pipe into the collection space of the laundry bag collector 3, and for passing refuse bags directly to the refuse bag collector.

The sorting means comprises a diverter tube 25 interposed between two open-ended sections 22, 23 of the conveying pipe 5.

One end 26 of the diverter tube 25 is secured to the upstream open-ended section 22 of the conveying pipe 5 by a flexible bellows 24, and the pipe section 25 is movable between a first position in which the other end 27 of the diverter tube 25 connects with the downstream open-ended section 23 of the conveying pipe 5 and a second position in which said other end 27 of the diverter tube 25 opens into the laundry bag collector 3, with control means being provided for controlling movement of the diverter tube 25 between the first and second positions.

The control means comprises a control cylinder 28 which when supplied with a fluid under pressure causes the diverter tube 25 to move from the first position to the second position. The control cylinder 28 is preferably operated pneumatically from a source of compressed air which is available for the operation of the chute isolating valves 14 and 15.

The exhauster system comprises three suction pumps or exhausters 29, which can be isolated from the pipe system by respective shut-off valves 30, and which are connected to a common manifold 31 connected in turn to a suction pipe 32 via two filters 33 arranged in parallel. The suction pipe 32 is connected to the inside of the refuse bag collector 4 and a branch pipe 34 connects the suction pipe 32 to the conveying pipe between the isolating valve 21 and the laundry bag collector 3. An isolating valve is provided between the suction pipe 32 and the refuse bag collector 4, and a bypass valve 36 is provided in the branch pipe 34.

The isolating valves 21 and 35 enable the refuse bag collector 4 to be isolated from the exhauster system.

A low-pressure ventilating fan 37 for ventilation purposes as will be described later is also con nected to the manifold 31 and is controllable by a shut-off valve 38.

The refuse bag collector is of a well-known type and includes a screw conveyor 39 for delivering a measured amount of refuse through an outlet 40 to an incinerator 41.

The operation of the system illustrated in the drawings will now be described.

Laundry bags and refuse bags are introduced into the storage spaces 12 and 13 through the outer doors 8 and 9 of the respective inlet stations 6 and 7. When a bag is introduced through an outer door 8, 9 it falls down into the storage space above the respective inner door 10, 11.

The bags accumulate in the storage spaces 12, 13 of the inlet stations 6, 7 and when one storage space is full or a specified number of storage spaces 12, 13 are full the programmer in response to the electrical signals from the sensors associated with the storage spaces 12, 13, provides an electrical signal which energises the exhauster system to initiate an evacuation cycle.

On commencement of the evacuation cycle the programmer causes the following events to take place: the exhausters 29 are started; the by-pass valve 36 is closed; the isolating valves 21 and 35 are opened; and the conveying pipe 5 is set to deliver refuse bags to the refuse bag collector 4 by supplying fluid pressure to the control cylinder 28 causing the diverter tube 25 to move from its second position to its first position in which it is "in line" with the open-ended sections 22, 23 of the conveying pipe 5.

The chute isolating valve 15 of a first refuse chute 2 is then opened so that an air flow is established through the system. Shortly before the chute isolating valve 15 is opened all of the outer doors 9 of that chute are locked so as to prevent any more refuse bags from being introduced into the inlet stations 7 of that chute 2 and a light outside each outer door 9 is illuminated to indicate that the door 9 is locked.

The programmer then releases the latch 17 to open the inner door 11 of the inlet station 7 on a first level of the first refuse chute 2 so that the refuse bags fall from that inlet station 7 down the chute 2 into the conveying pipe 5 whence they are conveyed along the conveying pipe 5 by the flow of air drawn from the top of the refuse chutes. The bags are conveyed through the laundry bag collector 3 to the refuse bag collector 4 where they fall into the collector 4 from the open end section 20 of the conveying pipe 5.

When the storage space 13 of the let station 7 on the first level of the refuse chute 2 has been emptied, the inner door 11 of that inlet station is closed and the inner door 11 of the inlet station 7 on a second level of the first refuse chute 2 is opened.

The refuse bags from the inlet station 7 on the second level are then conveyed to the refuse bag col lector 4 in a similar manner to those of the inlet station on the first level and this process is re peated until the storage spaces 13 of all of the inlet stations 7 of the first refuse chute 2 have been emptied.

When the storage spaces 13 of all of the inlet stations 7 of the first refuse chute 2 have been emptied, the chute isolating valve 15 of that chute 2 is closed, the outer doors 9 of all of the inlet stations 7 of the first refuse chute 2 are unlocked, and the lights outside the outer doors are extinguished.

The chute valve 15 of a second refuse chute 2' is then opened and the outer doors 9 of all of the inlet stations 7 of that,chute are locked. The refuse bags from the storage spaces 13 of the second refuse chute 2' are then conveyed to the refuse bag collector 4 in a similar manner to those of the first chute 2 and this process is repeated for all the remaining refuse chutes until all of the storage spaces of the last refuse chute have been emptied.

When the storage spaces 13 of all the refuse chutes 2 have been emptied and the chute isolating valve of the last refuse chute is closed, the programmer opens the by-pass valve 36 and closes the isolating valves 21 and 35 thereby isolating the refuse bag collector 4 from the exhauster system.

The programmer then sets the system to empty the laundry chutes 1 and, at this time, may also initiate a refuse discharge sequence as will be described later. The laundry bag collector 3 is first set to accept laundry bags by admitting fluid pressure to the other side of the piston in the control cylinder 28 causing the diverter tube 25 to move from its first position to its second position. The chute isolating valve 14 of a first laundry chute 1 is then caused to open by the programmer so that an air flow through the system is established. Shortly before the chute isolating valve 14 is opened, all of the outer doors 8 of that chute 1 are locked so as to prevent any more laundry bags from being introduced into the inlet stations 6 of the laundry chute. A light outside each outer door 8 is illuminated to indicate that the door 8 is locked.

The programmer then releases the latch 16 to open the inner door 10 of the inlet station 6 on a first level of the first laundry chute 1 so that the laundry bags fall from that inlet station 6 down the chute 1 into the conveying pipe 5 whence they are conveyed by the flow of air drawn from the top of the laundry chute 1 along the conveying pipe to the laundry bag collector 3 where they fall into the collector 3 from the pipe section 25.

When the storage space 12 of the inlet station 6 on the first level of the laundry chute 2 has been emptied, the inner door 10 of that inlet station is closed and the inner door 10 of the inlet station 6 on a second level of the first laundry chute 1 is opened. The laundry bags from the inlet station 6 on the second level are then conveyed to the laundry bag collector 3 in a similar manner to those of the inlet station 6 on the first level and this process is repeated until the storage spaces 12 of all of the inlet stations 6 of the first laundry chute 1 have been emptied.

When the storage spaces 12 of all of the inlet stations 6 of the first laundry chute 1 have been emptied the chute isolating valve 14 of that chute 1 is closed, the outer doors 8 of all of the inlet stations 6 of the first laundry chute 1 are unlocked, and the lights outside the outer doors 8 are extin guished. The chute isolating valve 14 of a second laundry chute 1' is then opened and the outer doors 8 of all of the inlet stations 6 of that chute are locked. The laundry bags from the storage spaces 12 ofthe second laundry chute 1' are then conveyed to the laundry bag collector 3 in a similar manner to those of the first chute 1 and this process is repeated for all the remaining laundry chutes until the storage spaces 12 of the last laundry chute have been emptied.

When the storage spaces 12 of all the laundry chutes 1 have been emptied and the chute isolating valve 14 of the last laundry chute 1 is closed, the pipe section 25 is moved from its second position to its first position, the shut-off valves 30 for the exhausters 29 are closed and the electricity supply to the exhausters is switched off.

The evacuation cycle is then completed; laundry bags and refuse bags may be introduced once again into the inlet stations 6 and 7 of the laundry chutes 1 and refuse chutes 2. The programmer then waits until the specified number of storage spaces of the inlet stations 6, 7 are full before initiating another evacuation cycle.

The bags of refuse may be transferred from the refuse bag collector 4 to the incinerator 41 for burning at any convenient time between evacuation cycles.

However, the refuse bags are preferably discharged from the refuse bag collector 4 to the incinerator 41 during the period of the evacuation cycle in which laundry bags are conveyed from the inlet stations 6 of the laundry chutes 1 to the laundry bag collector 3. In this case the programmer ignites the incinerator 41 at the start of the evacuation cycle so the temperature of the incinerator can rise to a sufficiently high value for burning during the period in which refuse bags are conveyed to the refuse bag collector 4. When the programmer sets the system to empty the inlet stations 6 of the laundry chutes 1 and when the incinerator 41 has reached a sufficiently high temperature for burning, the programmer energises the screw conveyor 39 to discharge the refuse bags to the incinerator 41.

When the refuse bags are discharged to the incinerator the programmer ensures that the by-pass valve 36 is open and that the isolating valves 21 and 35 are closed to isolate the refuse bag collector 4 from the exhauster system. This prevents flames from the incinerator from being drawn into the refuse bag collector 4.

At any time between evacuation cycles, bags of laundry may be removed from the laundry bag collector 3 for cleaning. The laundry bag collector 3 is formed with a base plate 42 hinged along one side which is pneumatically movable into an open position (shown by broken lines in Figure 1) to allow the laundry bags to fall out of the collector 3.

The low pressure ventilating fan 37 is arranged to operate all of the time when the exhausters 29 are shut down and the chute isolating valves 14 and 15 may be opened or be constructed in such a manner as to allow some flow of air through the system which helps to remove smells and germs from the system. When the fan 37 is operating the isolating valves 21 and 35 are closed, the by-pass valve 36 is open and the pipe section 25 occupies its first position in which it is "in line" with the open-ended sections 22, 23 so that air drawn through the system by-passes the refuse bag collector 4 and the laundry bag collector 3.

An important feature of the system is that a laundry bag introduced through an outer door 9 of an inlet station 7 of a refuse chute 2 is detected by the detection means associated with that inlet station 7 and can be removed from the inlet station before it is conveyed to the refuse bag collector 4.

Similarly, a refuse bag introduced through the outer door 8 of an inlet station 6 of a laundry chute 1 is detected by the detection means associated with that inlet station 6 and can be removed from the inlet station 6 before it is conveyed to the laundry bag collector 3.

Claims

CLAIMS 1. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations comprising a conveying pipe common to the different kinds of goods wherein is provided sorting means enclosed within a chamber and movable between first and second positions, the sorting means in the first position affording continuity of the conveying pipe through the chamber and in the second position directing goods out of the conveying pipe into the chamber. 2. A pneumatic conveying system according to claim 1 which includes a plurality of sorting means, each of which is enclosed within an associated chamber and is movable between said first and second positions. 3. A pneumatic conveying system according to claim 1 or claim 2 wherein the or each chamber is provided with a door or doors for the removal of goods collected in the chamber, the arrangement being such that the door or doors are prevented from being opened while sub-atmosphere pressure subsists within the chamber. 4. A pneumatic conveying system according to any one of the preceding claims in which the or each sorting means seals the pipe from the chamber in its first position. 5. A pneumatic conveying system according to any one of the preceding claims wherein the or each sorting means comprises a diverter mounted for angular movement about its junction with the upstream side of the conveying pipe. 6. A pneumatic conveying system according to claim 5 wherein the director is joined to the upstream side of the conveying pipe by a flexible joint. 7. A pneumatic conveying system according to any one of the preceding claims wherein control means is provided for moving the sorting means between its first and second positions. 8. A pneumatic conveying system according to any one of the preceding claims wherein the collecting points comprise inlet stations at which the goods may be assembled prior to release into or towards the conveying pipe. 9. A pneumatic conveying system according to claim 8 wherein the inlet stations comprise an outer door forming an entry for goods into the system, an inner door leading into or towards the conveying pipe and a storage space between the inner and outer doors. 10. A pneumatic conveying system according to claim 9 wherein the inner door of the inlet station is movable between an open position in which it permits the onward transmission of goods from the associated storage space to the conveying pipe and a closed position in which it prevents said transfer of goods, the inner door being so constructed and arranged to allow sufficient passage of air through andlor around the inner door in its closed position so as to equalise the pressure on each side of the inner door. 11. A pneumatic conveying system according to claim 10 wherein control means is provided for controlling movement of the inner door between its open and closed positions. 12. A pneumatic conveying system according to any one of claims 8 to 11 wherein the inlet stations are provided with sensing means for sensing when a predetermined amount of goods has been assembled at the inlet station. 13. A pneumatic conveying system according to any one of the preceding claims wherein a plurality of chutes or branch pipes connected to the main conveying pipe is provided to receive goods from the collecting points. 14. A pneumatic conveying system according to claim 13 wherein isolating valves are provided for isolating the chutes or branch pipes from the main conveying pipe. 15. A pneumatic conveying system according to claim 13 or claim 14 wherein the chutes or branch pipes serve a number of collecting points for one of the kinds of goods. 16. A pneumatic conveying system according to claim 13 or claim 14 wherein the chutes or branch pipes are common to collecting points ior different kinds of goods. 17. A pneumatic conveying system according to any one of the preceding claims wherein detection means is provided at each collecting points for detecting the wrong kind of goods at that collecting point. 18. A pneumatic conveying system according to claim 17 wherein the detection means produces an alarm signal and/or prevents the onward transmission of goods into the system when it detects the wrong kind of goods at that collecting point. 19. A pneumatic conveying system according to any one of the preceding claims wherein a programmer is provided for controlling the whole or part of the operation of the whole or parts of the system. 20. A pneumatic conveying system according to claim 19 wherein the programmer controls the whole or part of the operation of the system during evacuation or conveying cycles in which the different kinds of goods are conveyed to the various destinations. 21. A pneumatic conveying system according to claim 19 as appended to claim 12 wherein the programmer governs assessment of the need for evacuation or conveying cycles in response to signals from the sensing means at the inlet stations. 22. A pneumatic conveying system according to claim 19 wherein the programmer governs determination of the kinds of goods to be dealt with in an individual evacuation or conveying cycle and the appropriate actuation of the sorting means. 23. A pneumatic conveying system according to claim 19 or 20 as appended to claim 12 wherein the programmer governs determination of the sequence in which goods are removed from the various collecting points or chutes or branch pipes. 24. A pneumatic conveying system according to claim 19 wherein the programmer governs the starting and stopping of exhausters or suction pumps for producing a sub-atmospheric pressure within the conveying pipe, and the opening and closing of the necessary valves at each stage of the programme. 25. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations substantially as described herein with reference to the accompanying drawings. 26. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations incorporating a number of inlet stations of the type substantially as described herein with reference to Figure 2 of the accompanying drawings. 27. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations incorporating a number of inlet stations of the type substantially as described herein with reference to Figure 3 of the accompanying drawings. Amendments to the claims have been filed, and have the following effect: New or textually amended claims hve been filed as follows: CLAIMS

1. A method of moving goods of different kinds from a number of collecting points and delivering them to various destinations comprising the steps of collecting the different kinds of goods at the collecting points, establishing an air flow through a conveying pipe common to the different kinds of goods, releasing the goods of one kind from the collecting point or collecting points into the conveying pipe and, at the same time, preventing the release of goods of the other kind or kinds into the conveying pipe, pneumatically conveying the goods of the said one kind along the conveying pipe to a sorting location enclosed within a chamber which constitutes the destination for that kind of goods, directing the goods of the said one kind out of the conveying pipe and into the chamber, releasing the goods of a second kind from the col lecting point or collecting points into the conveying pipe and, at the same time, preventing the release of goods of the other kind or kinds into the conveying pipe, and pneumatically conveying the goods of the second kind along the conveying pipe through the sorting location and the chamber and to a destination for said second kind of goods further along the conveying pipe.

2. A method according to claim 1 wherein the goods are released from the collecting points into a plurality of chutes or branch pipes connected to the main conveying pipe before they enter the main conveying pipe.

3. A method according to claim 2 wherein the goods of each kind are collected at a number of collecting points on at least one chute or branch pipe specifically for that kind of goods.

4. A method according to claim 2 wherein the different kinds of goods are collected at collecting points on at least one chute or branch pipe common to the different kinds of goods.

5. A method according to any one of the preceding claims including the step of storing the goods in storage spaces at the collecting points before they are released into or towards the conveying pipe.

6. A method according to claim 5 including the further steps of sensing at each storage space when a predetermined amount of goods has been stored in the storage space, and delaying the release of goods into or towards the conveying pipe until one or a specified number of storage spaces contain the predetermined amount of goods.

7. A method according to any one of the preceding claims including the step of detecting the wrong kind of goods at the collecting points.

8. A method according to claim 7 including the further step of preventing the release of goods from a collecting point into or towards the conveying pipe when the wrong kind of goods is detected at that collecting point.

9. A method according to any of the preceding claims wherein the goods of one kind are bags of soiled laundry and the goods of another kind are bags of refuse.

10. A pneumatic conveying system for moving goods of different kinds by the method according to claim 1 comprising a number of collecting points for goods of one kind and a number of collecting points for goods of another kind, a ccnveying pipe common to the different kinds of goods, a destination for goods of one kind which comprises a chamber at a sorting location along the conveying pipe, a destination for goods of another kind further along the conveying pipe, and sorting means enclosed within the chamber and movable between first and second positions, the sorting means in the first position affording continuity of the conveying pipe through the chamber and in the second position directing goods out of the conveying pipe into the chamber.

11. A pneumatic conveying system according to claim 10 which includes a plurality of sorting means, each of which is enclosed within an associated chamber and is movable between said first and second positions.

12. A pneumatic conveying system according to claim 10 or claim 11 wherein the or each chamber is provided with a door or doors for the removal of goods collected in the chamber, the arrangement being such that the door or doors are prevented from being opened while sub-atmospheric pressure subsists within the chamber.

13. A pneumatic conveying system according to any one of claims 10 to 12 in which the or each sorting means seals the pipe from the chamber in its first position.

14. A pneumatic conveying system according to any one of claims 10 to 13 wherein the or each sorting means comprises a diverter mounted for angular movement about its junction with the upstream side of the conveying pipe.

15. A pneumatic conveying system according to claim 14 wherein the director is joined to the upstream side of the conveying pipe by a flexible joint.

16. A pneumatic conveying system according to any one of claims 10 to 15 wherein control means is provided for moving the sorting means between its first and second positions.

17. A pneumatic conveying system according to any one of claims 10 to 16 wherein the collecting points comprise inlet stations at which the goods may be assembled prior to release into or towards the conveying pipe.

18. A pneumatic conveying system according to claim 17 wherein the inlet stations comprise an outer door forming an entry for goods into the system, an inner door leading into or towards the conveying pipe and a storage space between the inner and outer doors.

19. A pneumatic conveying system according to claim 18 wherein the inner door of the inlet station is movable between an open position in which it permits the onward transmission of goods from the associated storage space to the conveying pipe and a closed position in which it prevents said transfer of goods, the inner door being so constructed and arranged to allow sufficient passage of air through and/or around the inner door in its closed position so as to equalise the pressure on each side of the inner door.

20. A pneumatic conveying system according to claim 19 wherein control means is provided for controlling movement of the inner door between its open and closed positions.

21. A pneumatic conveying system according to any one of claims 17 to 20 wherein the inlet stations are provided with sensing means for sensing when a predetermined amount of goods has been assembled at the inlet station.

22. A pneumatic conveying system according to any one of claims 10 to 21 wherein a plurality of chutes or branch pipes connected to the main conveying pipe is provided to receive goods from the collecting points.

23. A pneumatic conveying system according to claim 22 wherein isolating valves are provided for isolating the chutes or branch pipes from the main conveying pipe.

24. A pneumatic conveying system according to claim 22 or claim 23 wherein the chutes or branch pipes serve a number of collecting points for one of the kinds of goods.

25. A pneumatic conveying system according to claim 22 or claim 23 wherein the chutes or branch pipes are common to collecting points for different kinds of goods.

26. A pneumatic conveying system according to any one of claims to 25 wherein detection means is provided at each collecting point for detecting the wrong kind of goods at that collecting point.

27. A pneumatic conveying system according to claim 26 wherein the detection means produces an alarm signal and/or prevents the onward transmission of goods into the system when it detects the wrong kind of goods at that collecting point.

28. A pneumatic conveying system according to any one of claims 10 to 27 wherein a programmer is provided for controlling the whole or part of the operation of the whole or parts of the system.

29. A pneumatic conveying system according to claim 28 wherein the programmer controls the whole or part of the operation of the system during evacuation or conveying cycles in which the different kinds of goods are conveyed to the various destinations.

30. A pneumatic conveying system according to claim 29 as appended to claim 21 wherein the programmer governs assessment of the need for evacuation or conveying cycles in response to signals from the sensing means at the inlet stations.

31. A pneumatic conveying system according to claim 29 wherein the programmer governs determination of the kinds of goods to be dealt with in an individual evacuation or conveying cycle and the appropriate actuation of the sorting means.

32. A pneumatic conveying system according to claim 28 or 29 as appended to claim 22 wherein the programmer governs determination of the sequence in which goods are removed from the various collecting points or chutes or branch pipes.

33. A pneumatic conveying system according to claim 28 wherein the programmer governs the starting and stopping of exhausters or suction pumps for producing a sub-atmospheric pressure within the conveying pipe, and the opening and closing of the necessary valves at each stage of the programme.

34. A pneumatic conveying system according to any one of claims 10 to 33 wherein the goods of one kind are bags of soiled laundry and the destination for the laundry bags comprises a laundry bag collector and the goods of another kind are bags of refuse and the destination for the refuse bags comprises an incinerator or other waste disposal means.

35. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations substantially as described herein with reference to the accompanying drawings.

36. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations incorporating a number of inlet stations of the type substantially as described herein with reference to Figure 2 of the accompanying drawings.

37. A pneumatic conveying system for moving goods of different kinds from collecting points and delivering them to various destinations incorporating a number of inlet stations of the type substan tiaily as described herein with reference to Figure 3 of the accompanying drawings.