GB2162765A

GB2162765A - Multiple flow control device

Info

Publication number: GB2162765A
Application number: GB8519865A
Authority: GB
Inventors: Aftab Alam
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-08-07
Filing date: 1985-08-07
Publication date: 1986-02-12
Also published as: GB8519865D0; GB2162765B; GB8420103D0

Abstract

A multiple flow control device comprises a number of inlet tubes (2,3,4) coupled to a common outlet (23). Each inlet tube has a level detector (7,8,9) which senses the level of liquid in the tube. A valve (12,13,14) is included in each inlet tube and is opened by a control means (27) to allow sequential flow from each of the inlet tubes in turn. The device may be operated in a level detect mode or a timer mode, and includes a microprocessor, a dedicated real time integrated circuit and a lockable key pad for programming the microprocessor. <IMAGE>

Description

SPECIFICATION Multiple flow control device The present invention relates to a device for controlling flow of a number of different liquids from individual storage containers to other apparatus, particularly liquid chromatography columns.

In column chromatography, the substance under study is applied to a column. Application of various liquids to the column follows and the effluent is collected. Such operations, that is the application of various liquids to the column, are generally carried out by workers, one liquid after the other, thus requiring many hours of attendance.

There are not many devices available to automate the entire procedure of application of the various liquids to chromatography columns. The instruments which are available to do this are either integral parts of more sophisticated instruments, or lack compatability. Moreover, they are very expensive and beyond the reach of smaller organisations.

It is therefore the aim of the present invention to provide a simple, inexpensive device to allow liquids to be applied to a chromatography column sequentially and automatically.

According to the present invention a multiple flow control device comprising a plurality of inlets and at least one outlet, the device also including control means to effect automatic sequential flow of liquid from each of the inlets to the outlet.

Preferably each inlet includes sensing means to detect the level of liquid in each inlet, said sensing means being coupled to the control means.

The sensing means may be a photoelectric sensor, but any other type of sensor with a pulsed or level output may be used equally successfully, for example a fibre-optic sensor.

Thus a device in accordance with the present invention although particularly suitable for controlling flow of liquids, may also be used to control flow of other materials capable of providing a signal indicating to the sensing means a presence or absence of the material.

Preferably each inlet comprises an inlet tube fitted with a valve which may be opened to allow liquid flow from the inlet to the outlet, or closed to prevent such flow.

Preferably said valves comprise solenoid valves.

Preferably the control device includes a microprocessor, a dedicated real time integrated circuit, and a key pad for programming the microprocessor.

Preferably the microprocessor overlooks all the device components as well as monitoring the inlets and outlet.

Preferably the device is able to work in either of two basic modes, a timer mode and a level detect mode.

In the case of the device working in the level detect mode, the device will only work when there is a presence and subsequently an absence of liquid in the inlet tubes.

In the case of the device working in the timer mode, each of the channels associated with the inlets is programmed via the key pad to come on for a period of time sequentially, the channel only being enabled if there is presence of liquid in the associated inlet tube and the channel is within its "period on" time.

Preferably, when the device is in the timer mode, each valve in the inlet tubes will close and the next valve open if the level of liquid in that inlet tube falls below the level detector prior to the expiry of the programmed time period for that channel.

The key pad allows the user to program the individual period times for each channel, and also allows direct control of each channel.

Preferably the device includes an additional spare channel which is user-defined in that the output is offered via a standard 13A mains outlet.

Preferably the device includes a further output channel for connection to a fraction pump, this output channel only being active if there is a presence of liquid in any of the inlet tubes.

Preferably the device is able to be controlled remotely via a serial channel resident on the microprocessor, this serial channel also serving to allow transmission of status information to a remote master station.

Preferably the device includes within it a switch board power supply.

Preferably the key pad includes means to lock out the key pad for security reasons.

Preferably said locking means comprises a key switch so that once the user has programmed in the channel times, the times cannot be altered by mistakes or unauthorised personnel.

Preferably the device allows 224 switching times per week cycle.

Preferably the device includes the capability of manual overide on any output.

Preferably the device includes a 4 digit seven segment display which indicates the times for each channel as well as the day of the week and also indicates which output is active when the device is in the manual overide mode.

According to a further aspect of the present invention there is provided a method of supplying a plurality of different liquids from a plurality of liquid reservoirs, each through its own associated inlet to a common outlet, the method including supplying liquid from each reservoir in an automatically controlled sequential manner.

An 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 perspective view of a multiple liquid flow control device of the present invention, shown with an associated liquid chromatography column.

Figure 2 shows the internal components of the device of the present invention.

Figure 3 shows one way of supplying a measured volume of liquid to the chromatography column.

Figure 3A shows an alternative way of supplying a measured volume of liquid to the chromatography column; and Figure 4 shows the level detector assembly of a device of the present invention.

Referring to Figs 1 and 2, a multiple liquid flow control device comprises three inlet tubes 2,3,4 for receiving liquids from the reservoirs 18,19;20. The multiple liquid flow control device could contain any number of inlet tubes. However, for simplicity only three inlet tubes are shown.

Each inlet tube has sensing means comprising a liquid level detector 7,8,9 and an associated valve 12,13,14. The device runs on an electric power supply, the connection to this supply being indicated by 28. A switch board power supply is provided within the unit.

The detectors 7,8,9 could be any type of sensor having a pulsed or level output, for instance a photoelectric sensor.

The valves 12,13,14 are solenoid valves. The device includes a microprocessor and a dedicated real time integrated circuit, these being indicated generally by 27, dotted lines with crosses indicating electric cables.

The device includes an outlet tube 23 which may be attached to the top of a chromatography column. The liquids to be applied to the column are placed in each of the reservoirs 18,19,20 and connected by supply tubings, indicated by dotted lines with arrows, to the inlet tubes of the control device in appropriate order. The liquids are allowed to flow from the reservoirs beyond the level detectors 7,8,9. The multiple liquid flow control device may be set to the level detect mode. In this mode the liquid from the first reservoir 18 will flow through the first inlet tube 2, the solenoid valve 12 will remain open to allow free-flow of the liquid under gravity to the outlet tube 23 which supplies the liquid to a chromatography column 24. The effluent from the column could be collected by a fraction collector.

When a previously selected volume of the liquid is passed through the column, the level of the liquid will fàll to the level detector 7, and this information will be transmitted to the microprocessor and dedicated real time integrated circuit, which causes the valve 12 to close and concurrently the valve 13 in the next inlet tube 3 to open allowing free flow of the liquid from the second reservoir 19 through the second inlet tube 3.

This entire sequence of events is rep#eated from one inlet tube to the other until liquid from the last reservoir 20 has been applied to the column and the valve 14 in the last inlet tube 4 then remains closed.

In this level detect mode, the device will only work when there is a presence and subsequently an absence of liquid in the inlet tubes 2,3,4.

The device has four programmable channels, three being used for level detection and the fourth a spare channeL The spare channel is user-defined in that it is offered as a standard 13A mains outlet at the rear of the device.

The device may alternatively be used in a timer mode, i#n which each valve 12,13,14 is allowed to remain open for a specified period of time. At the end of that time period, the first valve 12 will close, concurrently the next valve 13 will open allowing free flow of liquid from the second reservoir 19 for a specified period of time. In this timer mode, each of the three channels associated with the three inlet tubes is programmed to come on for a period of time sequentially. The channel is only enabled if there is a liquid present in the appropriate inlet tube, and the channel is within its programmed "period on" time. If, however, the level of the liquid in the inlet tube falls below the level detector prior to the expiry of the programmed time period, the valve associated with that inlet tube will be closed and concurrently the next valve will be opened.As with the level detect mode, this sequence of events is repeated until the last valve 14 is closed at the end of the cycle.

The device includes a key pad which allows the user to program the individual period times for each channel, the same key pad also allowing direct control of each channel.

This key pad is able to be locked for security reasons, by means of a key switch, so that once the user has programmed in the channel times, the times cannot be altered by mistake or unauthorised personnel.

A further output channel is provided for connection to a fraction pump, and this output channel is -only enabled if there is liquid in any of the inlet tubes.

The device also includes the capability of being controlled remotely. This is achieved by means of a serial channel resident on the microprocessor, this channel also serving to allow transmission of status information to a remote master station.

The device includes a manual overide capability on any channel.

The device allows 224 switching times per week cycle, and includes a four digit seven segment display which indicates the programmed times for each channel as well as the day of the week and which output is active when the device is in the manual overide mode.

Figs 3 and 3A show how a measured volume of a liquid could be applied to a chromatography column. The reservoirs are g#raduated containers 28.

Liquid volume could be selected by simply adjusting the height of the supplying tube 25 or the depth of the supplying tube 26.

Each level detector 7,8,9 is a photoelectric sensor 29, as shown in Fig 4. The dome shaped detector 29 is housed in a casing 30 which comprises a liquid inlet 32 and an outlet 33. Liquid coming from the inlet 32 flows through the channel 31 and over the level detector 29 to the outlet 33. An air ex- haust channel 34 is provided for air to escape into (in the direc-tion- of the arrow) and thus allowing uninterrupted flow of liquid over the detector 29.

The multiple flow control device could be-used in operations other than chromatography where liquid or other materials need to be supplied automatically and sequentially. The device could be made to supply any number of liquids sequentially and automatically by adding more inlet tubes with level detectors and valves to the main instrument 1. The multiple liquid flow control device-is very simple in operation and also adaptable. It could easily be used in conjunction with a variety of other instruments.

Claims

1. A multiple flow control device comprising a plurality of inlets and at least one outlet, the device also including control means to effect automatic sequential flow of liquid from each of the inlets to the outlet.

2. A control device according to Claim 1 in which each inlet includes means to detect the level of liquid in each inlet, said sensing means being coupled to the control means.

3. A control device according to Claim 1 or Claim 2 in which the sensing means is a photoelectric sensor.

4. A control device according to any of the preceding Claims in which each inlet tube is fitted with a valve which may be opened to allow liquid flow from the inlet to the outlet, or closed to prevent such flow.

5. A control device according to Claim 4 in which the valves are solenoid valves.

6. A control device according to any of the preceding Claims which includes a microprocessor, a dedicated real time integrated circuit, and a key pad for programming the microprocessor.

7. A control device according to Claim 6 in which the microprocessor overlooks all the device components as well as monitoring the inlets and outlets.

8. A control device according to any of the preceding Claims which operates in a level detect mode.

9. A control device according to any of Claims 1 to 7 which operates in a timer mode.

10. A control device according to Claim 9 in which each valve in the inlet tubes will close and the next valve open if the level of liquid in that inlet tube falls below the level detector prior to ex piry of the programmed time period.

11. A control device according to any of Claims 6 to 10 in which the key pad includes locking means to lock out the key pad for security reasons.

12. A control device according to Claim 11 in which the locking means is a key switch.

13. A control device according to any of the preceding Claims which allows 224 switching times per week.

14. A control device according to any of the preceding Claims which includes the capability of manual overide of any output.

15. A control device according to any of the preceding Claims which includes a 4 digit seven segment display indicating the times for each channel as well as the day of the week and which output is active when the device is in manual overide mode.

16. A control device according to any of the preceding Claims which includes a switch board power supply.

17. A control device according to any of the preceding Claims which is able to be controlled remotely via a serial channel resident on the microprocessor.

18. A control device according to any of the preceding Claims in which there is provided an output channel for connection to a fraction pump, this output channel only being active if there is liquid present in any of the inlet tubes.

19. A control device according to any of the preceding Claims which includes a user defined output offered via a standard 13A mains outlet.

20. A method of supplying a plurality of different liquids from a plurality of liquid reservoirs, each through its own associated inlet, to a common outlet, the method including supplying liquid from each reservoir in an automatically controlled sequential manner.

21. A method according to Claim 20 and substantially as herein described.

22. A method of supplying a plurality of different liquids from a plurality of liquid reservoirs substantially as herein described with reference to the accompanying drawings.

23. A control device according to Claim 1 and substantially as herein described.

24. A multiple flow control device substantially as herein described with reference to the accompanying drawings.