CA2001699A1

CA2001699A1 - Compressed air dispensing machine

Info

Publication number: CA2001699A1
Application number: CA 2001699
Authority: CA
Inventors: David F. Wellstead; Peter W. Ormrod
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-10-28
Filing date: 1989-10-27
Publication date: 1990-04-28
Also published as: DK536389A; EP0366464A2; NO894293L; EP0366464A3; AU4388389A; NO894293D0; DK536389D0; JPH02264169A; GB8825227D0; FI895124A0

Abstract

ABSTRACT OF THE DISCLOSURE
A compressed air dispensing machine for supplying compressed air to diving cylinders comprises a housing containing a compressor for generating air under pressure, a storage chamber to which the air under pressure is fed, a filtration unit for purifying the air to breathing standards, an outlet line from the storage chamber and to which the diving cylinder can be attached, and a control unit for controlling the dispensing of compressed air from the storage chamber. The machine further comprises a safety tank to which the outlet line feeds and into which the empty cylinder must be located prior to filling, the control unit and the safety tank being-interconnected with the storage chamber in such a manner that access to compressed air from the outlet line is provided only on closure of the safety tank together with actuation of the control unit.

Description

;:~0~3~6~39 This invention relates to compressed air dispensing machines and more particularly to such machines for supplying compressed air to diving cylinders.
Conventional diver's cylinders contain compressed air at a pressure usually within the range 3000 to 3400 psi, the volume of air in the cylinders being sufficient to last the diver about 45 minutes.
When is it necessary to replenish a cylinder, a diver takes his empty cylinder to a shop or club having a compressor, usually electrically driven although some are diesel operated, and the cylinder is manually filled by an operator who connects the cylinder to the compressor, switches on the compressor, fills the cylinder, switches off the compressor, removes the cylinder and charges the diver an agreed amount.
Clearly this a tedious and time-consuming operation, requiring the presence of an operator to carry out the filling procedure and to take the payment from the diver.
It has been proposed to provide custom-built machines specifically designed to fill diving cylinders with compressed air but these known machines are all substantial, static systems and still suffer from the aforementioned disadvantage of requiring an operator to be present to actuate the machine and to receive the payment from the diver.

~016~9 It is an ob;ect of the invention to provide a machine for supplying compressed air which is substantially automatic in its operation and which eliminates the necessity for the presence of an operator (other than the user himself).
According to the present invention, there is provided a compressed air dispensing machine comprising a housing in which are contained a compressor for generating air under pressure, a storage chamber to which said air under pressure is fed from the compressor, and an outlet line from the storage chamber to which a container to be filled can be attached, the housing further containing a filtration unit for purifying the compressed air to breathing standards, and a control unit for controlling the dispensing of compressed air from the storage chamber, the machine further comprising a safety tank to which the outlet line feeds and into which the container to be supplied with compressed air must be located prior to filling, the control unit and the safety tank being interconnected with the storage chamber in such a manner that, on closure of the safety tank and on actuation of the control unit, access is provided to a predetermined volume of compressed air from the outlet line.
Thus it will ~e appreciated that a diver with an empty cylinder can himself locate the cylinder in the safety tank, connect the outlet line to the cylinder, close the safety tank and himself control the filling of the cylinder after appropriate actuation of the control unit. The machine ef~ectively comprises a fully automatic, self-service unit eliminating the requirement for an operator.
Conveniently the outlet line is interconnected with thestorage chamber through a control valve, conveniently an air-solenoid valve, which is opened only on closure of the safety tank to~ether with actuation of the control unit.
Actuation of the control unit may be achieved by the insertion therein of a monetary unit of a predetermined value, either cash or a prepaid monetary token.
Alternatively said actuation may be achieved by the insertion into the control unit of an authorised token, key, slide card or the like.
The outlet line may further include, downstream of the control valve, a regulator valve under the control of the user to provide access to the predetermined volume of compressed air.
Preferably the storage chamber includes pressure sensing means therein interconnected with the compressor whereby pressure within the storage chamber is maintained between predetermined maximum and minimum values.
The safety tank may comprise an armoured metal tank f illed with water.
Preferably the machine includes a central programmer by which the compressor, the storage chamber, the control unit and the safety tank are interconnected with one another.

~oo~L~9~3 An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing which is a block schematic drawing of a compressed air dispensing machine.

~ eferring to the drawing, an air dispensing machine is shown and comprises a housing 2 in which are contained a diesel motor 4 driving an air compressor 6. Compressed air from the compressor 6 is fed through a purifier and cooler unit 8 containing a filter element and thence to a storage chamber 10 by way of a one-way valve 12. An outlet line 14 feeds from the storage chamber 10 to a connection point on the housing 2, a pressure control valve 16, conveniently an air solenoid valve, being contained in said line 14.
The housing further contains a control unit 18 provided with receiving slots 20,22 for both cash and a monetary token or coded card, the control unit 18 being interconnected with the storage chamber 10 in such a manner that, on insertion of the appropriate monetary unit, whether cash or token, a sensor within the control unit 18 is actuated to trigger the air solenoid valve in the outlet line 14 and a timing mechanism in preparation for making available a predetermined volume of compressed air from the storage chamber.
All the above-described components 4,6,8,10,18 each have a monitor Ml-M5 respectively associated therewith, said components and their respective monitors being 2~01699 connected to one another and to a central programmer 24.
More particularly, monitor Ml associated with the drive motor 4 senses engine temperature, oil pressure and engine speed and feeds the relevant information to the programmer 24.
The monitor M2 senses the temperature of the compressor 6, the temperature of the oil in the compressor 6 and the condition of the drive belt of the compressor 6 as well as controlling the sequence of operation of the compressor 6 into start, compress and cool down stages.
The conditlon of the filter element within the purifier and cooler unit 8 is sensed by the monitor M3, while monitor M4 constantly monitors the pressure of compressed air contained within the storage chamber 10 as will be discussed in more detail below.
The monitor M5 associated with the control unit 18 senses when cash or a token is inserted into the slot 20 or 22 and instructs the programmer 24 accordingly, again as will be detailed below.
The machine further includes, externally of the housing 2, an armoured safety tank 26 full of water and adapted to receive therein the cylinder to be replenished with compre~sed air during the filling operation. The location of the cylinder in the tank 26 protects the user in the event of failure of the cylinder during filling thereof.
More particularly, the tank 26 includes a lid and is provided with a monitor M6 determining the condition of the ZOOl~i99 lid on the tank 26 and interlocked with the programmer 24 to advise the programmer of said condition. The machine and the appropriate signal to this effect is supplied to the progra~mer 24 by way of the monitor M6.
The described machine operates as follows. A flexible supply line 28 feeds from the outline line 14 to the tank 26, said line 28 incorporating an on-off control valve 30.
The user locates his empty cylinder in the tank 26, connects the supply line 28 to the cylinder and ensures that the lid of the tank 26 is closed. He inserts the appropriate money into slot 20 or prepaid token into the slot 22, thus activating the control unit 18 and triggering the programmer 24 whereby the solenoid valve 16 in the supply line 14 is electrically opened and compressed air from the storage chamber lO is available for a pre-set time determined by a timing mechanism again under the control of the programmer 24.
The user then opens the valve 30 and fills his cylinder, a gauge on the housing 2 indicating the pressure involved. Once the cylinder is full, the user closes the valve 30, operates a vent on the valve 30 to release the pressure in the line between the valve 30 and the cylinder and then removes the cylinder from the tank 26.
Within the housing 2, the drive motor 4 and compressor 6 are interlinked such that, on a start signal being fed to the diesel motor 4, the compressor adopts a warm-up cycle 2 with no pressure being developed for 2 minutes.

~001699 The compressed air subse~uently developed by the compressor 6 is cooled, dried and purified to BS4275 and DIN 3188 by the unit 12 prior to passage to the storage chamber 10 where it is stored at a working pressure of, typically, 5000 psi.
The chamber 10 incorporates pressure switches Pl and P2 which detect when the pressure in the chanmber 10 exceeds a maximum permissible value - e.g. 5000 psi - and a minimum permissible value - e.g. 4500 psi - respectively. Tripping of the switches P1 and P2 sends 'stop' and 'start' signals respectively to the motor-4 and compressor 6 to maintain the supply of compressed air between these desired values.
The chamber 10 may typically require replenishing with compressed air after about 10 cylinder fillings.
The control valve 16 can be pre-set to maximise the pressure of air available to a customer, typically to between 3000 and 3400 psi.
Prepaid vending cards or tokens enabling up to 10000 fills may be available to users, while the machine may be supplied with two flexible supply hoses, one appropriate to monetary inserts into slot 20 and the other to token inserts into slot 22.
The programmer 24 is programmed amongst other things to determine the price of a vend, to count the cash taken by the slot 10, to count the number of token operations via slot 22, to sense closure of the lid of the safety tank 26, to time the length of a vend (typically 5 minutes) and to ~0(316~9 ensure that the supply of compressed air to the user is determined as soon as the supply line 28 i5 vented on closure of the valve 30.
The machine is preferably powered by a 24 volt battery pack backed up by 240 volts AC mains feed to the programmer 24, which programmer incorporates an LED display panel.
A plurality of machines as detailed above may be scattered around a country with the programmers 24 of each machine coupled to a central computer 32 which interfaces with the individual machines to give an over-view of the network state at any given time and whereby servicing and maintenance schedules can be built around this centralised information.
A typical machine according to the invention may be 10 feet high by 10 feet wide by 8 feet 6 inches deep and as such may comprise a portable, free-standing structure.
The above described machine enables the sale of metered volumes of compressed air to private divers as and when required, the machines being provided at suitable locations throughout the country and requiring the insertion therein of predetermined monetary units before air will be dispensed to the user.
Alternatively, for example when being used by the armed forces, the control unit of the machine may be actuated other than by monetary units, as by the insertion therein of a symbol of authority such as an authorised token, a key, a slide card or the like.

Claims

WE CLAIM:

1. A compressed air dispensing machine for filling a container, the machine comprising a housing, said housing containing a compressor for generating air under pressure, a storage chamber to which said air under pressure is fed from the compressor, and an outlet line from said storage chamber to which the container to be filled can be attached, the housing further containing a filtration unit for purifying the compressed air to breathing standards, and a control unit for controlling the dispensing of compressed air from the storage chamber, the machine further comprising a safety tank to which the outlet line feeds and into which the container to be supplied with compressed air must be located prior to filling, the control unit and the safety tank being interconnected with the storage chamber in such a manner that, on closure of the safety tank and on actuation of the control unit, access is provided to a predetermined volume of compressed air from the outlet line.

2. A machine as claimed in claim 1 and comprising a control valve in the outlet line from the storage chamber, said control valve being opened only on closure of the safety tank together with actuation of the control unit,

3. A machine as claimed in claim 2 in which actuation of the control unit is achieved by the insertion therein of a monetary unit of a predetermined value.

4. A machine as claimed in claim 3 in which the monetary unit comprises either cash or a prepaid monetary token.

5. A machine as claimed in claim 2 in which actuation of the control unit is achieved by the insertion therein of an authorised token.

6. A machine as claimed in claim 2 and comprising a regulator valve in the outlet line downstream of the control valve, said regulator valve being under the control of the user to provide access to the predetermined volume of compressed air.

7. A machine as claimed in claim 1 and comprising pressure sensing means in the storage chanber, said pressure sensing means being interconnected with the compressor whereby pressure within the storage chamber is maintained between predetermined maximum and minimum values.