GB1577499A - Apparatus for determining the depth of beer in a keg - Google Patents

Description

(54) APPARATUS FOR DETERMINING THE DEPTH OF BEER IN A KEG (71) We, THE DISTILLERS COM PANY (CARBON DIOXIDE) LIMITED, a British Company, of Cedar House, 39 London Road, Reigate, Surrey, RH2 9QE do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: One kind of beer keg has an opening at its top provided with a self-closing valve and a spear, which is a tube extending downwards into the keg from the valve. Such kegs are subsequently referred to as "kegs of the kind described".To draw beer from such a keg, a fitting is applied to the opening and carbon dioxide is applied under pressure through the fitting to the space within the keg outside the spear so that the pressure of the carbon dioxide acts on the surface of the beer in the keg and the beer is forced upwards through the spear and out through a duct which extends through the fitting and communicates with the inside of the spear.

Such kegs are subsequently referred to as kegs of the kind described.

Sometimes such kegs are returned by publicans to the brewery in a partly filled state. This happens in particular if the beer has gone off and cannot be sold. Under these circumstances if the beer is unsaleable for a reason which is no fault of the publican, the publican is credited with the value of the beer remaining in the keg. It is therefore necessary to be able to assess the volume of beer remaining in the keg and for this to be agreed with the publican when a partly filled keg is returned. The kegs are made of an opaque material, which is usually metal although some are made of plastics material, and therefore the amount of beer remaining cannot be seen.The kegs are kept under a top pressure of carbon dioxide and if the keg is opened to enable it to be dipped to ascertain the depth of beer remaining, the carbon dioxide top pressure is released and this in itself causes the beer to deteriorate very rapidly. Therefore if a keg is opened, it becomes impossible for the brewery to determine for sure whether or not the beer has been maltreated by the publican and therefore whether or not he should be credited with the value of the returned beer.

For these reasons it has become accepted practice to lift the kegs manually and to assess their contents in a very rough and ready manner by estimating their weight.

Even this very approximate technique cannot however by applied to large kegs which are too heavy to be lifted manually while they still contain any appreciable quantity of beer.

It is not practicable for a brewery representative to take both lifting apparatus and weighing apparatus to public houses to determine the contents of kegs to be returned as this would be far too timeconsuming.

The aim of the present invention therefore is to provide an apparatus for determining the depth of beer above the bottom of the spear in a keg of the kind described above which is pressurised with carbon dioxide, the apparatus being so constructed that it may be made portable and will very rapidly provide an indication of the depth required.

According to this invention such apparatus comprises a fitting for attachment to the opening of the keg, the fitting having two fluid ducts through it, a first of the ducts leading to the inside of the spear and the second of the ducts leading to the gas space outside the spear when the fitting is, in use, fitted to a keg, an upright tube or chamber, which has means for providing an indication when beer has risen to a predetermined level within it the tube or chamber being connected to the first duct and being located above the fitting, a differential pressure gauge connected to the second duct and to the tube or chamber above the predetermined level to measure the pressure differential between the gas space and the tube or chamber while the tube or chamber is closed, and a valve device for venting the tube or chamber to allow the beer from the keg to be raised within the tube or chamber by the gas pressure in the keg to the predetermined level and then closing the tube or chamber again, whereby the differential pressure gauge provides an indiction of the level of beer remaining in the keg above the bottom of the spear when the beer is held at the predetermined level and the valve device is closed.

This apparatus can be used extremely simply and quickly to provide an indication of the depth of beer above the bottom of the spear in a keg of the kind described by applying the fitting to the opening of the keg so that the self-closing valve of the keg is opened and the inside of the spear is set in communication with the inside of the upright tube or chamber. The valve device is opened to vent the tube or chamber to allow the beer from the keg to be raised by the pressure in the gas space of the keg to the predetermined level and then the valve device is closed again. The reading of the differential pressure gauge is then equal to the pressure generated by the column of beer in the spear and in the upright tube or chamber between the surface of the beer in the keg and the predetermined level.The relationship between the differential pressure and the height of this column will be dependent upon the specific gravity of the beer, but a calibration graph or table can be provided to give a direct indication of the height of the column of beer for each differential pressure gauge reading or indeed, for kegs of a given size and shape, the graph or table may give a direct reading of the beer contents remaining in the keg for each differential pressure reading.

The valve device may be manually operated and in this case it may be in the form of a simple cock or spool valve or alternatively the valve device may be electrically operated and may then comprise a solenoid valve which is controlled by a level switch which is operated automatically when the beer reaches the predetermined level in the tube or chamber.

The level switch may be a magnetic reed or microswitch and in this case a magnetic float is provided in the tube or chamber and this float operates the magnetic switch when the beer has risen in the tube or chamber to the predetermined level.

In some cases the carbon dioxide pressure within the keg may have been allowed to fall so low that it is insufficient to raise the beer remaining in the keg up to the predetermined level in the upright tube or chamber.

Indeed, it may be this lack of carbon dioxide pressure within the keg which has caused the beer to deteriorate so that it cannot be sold and is returned by the publican to the brewery.

Preferably, therefore, a pressure gauge is connected to the second duct to indicate the carbon dioxide pressure in the gas space of the keg as soon as the fitting is fitted to the opening of the keg and a connection is made both from the valve device and to the second duct from a coupling for connection to a carbon dioxide cylinder.

The valve device may then comprise two valves or a complex multi-way valve which enables the carbon dioxide under pressure from the cylinder to be applied initially both through the second duct to the gas space within the keg and also to the upright tube or chamber above the predetermined level.

When this is done, the initial step after the fitting has been fitted to the opening of the keg is to apply carbon dioxide at the same pressure both to the gas space and to the upright tube or chamber and hence through the spear so that the differential pressure gauge is subjected to two equal pressures and provides a zero reading. After this the valve device or the valves are reset to disconnect the carbon dioxide cylinder and to vent the carbon dioxide from the upright tube or chamber until the beer reaches the predetermined level in the same way as the apparatus is operated when there is already a sufficient carbon dioxide pressure in the gas space to force the beer up to the predetermined level in the tube or chamber without the use of an outside source of carbon dioxide under pressure.

An example of an apparatus in accordance with the invention is illustrated highly diagrammatically in the accompanying drawing.

Referring to the drawing, a beer keg 1 has an opening 2 fitted with a self-closing valve which is not shown. The apparatus in accordance with the invention comprises a fitting 3 which is arranged to be fitted to the opening 2 and, when so fitted, opens the self-closing valve.

The fitting 3 has a first duct 4 which communicates with a spear 5 inside the keg 1 and a second duct 6 which communicates with a gas space 7 within the keg 1 above the top surface 8 of beer within the keg.

The first duct 4 leads to an upright transparent tube 9 which has a closed upper end. A pipe 10 leads through the side wall of the tube 9 and has an open upper end 11 near the top of the tube 9. The pipe 10 leads to a differential pressure gauge 12 and this gauge is also connected to the second duct 6 by a pipe 13. The gauge 12 thus registers the pressure differential between a pressure P1 in the space 7 and a pressure P2 within the upper part of the tube 9.

The part of the gauge 12 which is subjected to pressure through the pipe 13 has a further pipe 14 leading from it to a pressure gauge 15 which thus indicates the pressure P1 within the space 7. A branch 16 from the pipe 14 leads to a first port 17 of a three-way solenoid valve 18. A second port 19 of this valve leads to a throttled venting jet 20 and a third port 21 of the valve 18 is connected by a pipe 22 to a first port 23 of a second three-way solenoid valve 24. A second port 25 of the valve 24 is closed and a third port 26 is connected by a pipe 27 to the part of the pressure gauge 12 to which the pipe 10 is connected so that the port 26 leads through the pipes 27 and 10 and a part of the gauge 12 to the upper part of the tube 9.

The solenoid valves 18 and 24 are controlled by an electric circuit which is not shown, but which includes a magnetic level switch 28 which may be mounted on the outside of the wall of the tube 9 as shown, or within the part of the pipe 10 inside the tube 9. The switch 28 is operated by an annular float which carries an annular magnet 30 within the tube 9.

In operation, the fitting 3 is applied to the opening 2 of the keg 1 as aready described and at this stage no electric power is supplied to either of the solenoid valves 18 and 24. Under these circumstances the connections within the valves are as shown in full lines in the drawing so that the pressure P1 in the space 7 passes through one side of the differential pressure gauge 12, thence through the valves 18 and 24 to the other side of the pressure gauge 12 and from there to the top of the tube 9. The pressure P1 therefore pertains throughout the system and the beer in the keg 1 remains at the level 8 both inside and outside the spear 5.

Power is now supplied to the solenoid valve 18, but not to the valve 24 and this causes the connection in the valve 18 to be changed over to the dotted line position shown in the drawing. Accordingly the branch 16 is shut off so that one side of the pressure gauge 12 remains at the pressure P1, but the space within the tube 9 is vented through the pipes 10 and 27, the valve 24 and the valve 18 to the throttled vent 20.

Accordingly the pressure in the tube 9 gradually falls below P1 and beer is forced by the pressure P1 in the space 7 upwards through the spear 5 and the duct 4 into the tube 9.

As the beer level in the tube 9 rises, the float 29 with the magnet 30 also rise and when the beer reaches the predetermined level, which is a height h2 above the bottom of the spear 5, the magnet 30 operates the switch 28 and this energises the valve 24 so that it changes over to the dotted line position shown in the drawing. This closes the valve 24 and prevents further venting of the upper part of the tube 9 so that the beer remains at the predetermined level.

The pressure gauge 12 now gives a reading of the pressure differential between the pressure P1 in the space 7 and the pressure P2 in the upper part of the tube 9. This pressure differential corresponds to the height hl between the surface 8 of the beer in the keg and the predetermined level. It therefore gives an indication of h2 minus hl which is the depth of beer remaining in the keg above the bottom of the spear 5 and hence gives an indication of the volume of beer remaining in the keg.

Instead of the electrically operated arrangement described, the solenoid valve 18 may be substituted by a three-way cock and the solenoid valve 24 may be substituted by a two-way cock or alternatively both of these valves may be substituted by a single multiport manually operated spool valve.

The cocks or valve are operated manually in the same way as the solenoid valves 18 and 24 are operated automatically, the cock which takes the place of the solenoid valve 24 being closed when the beer level is seen to reach the predetermined level which is indicated by a line around the tube 9 which is transparent.

Whether the apparatus is operated electrically with solenoid valves or manually with cocks or a spool valve, the pipe 14 may have a connection leading to a coupling for fitting to a carbon dioxide cylinder. In this case, if the pressure P1 is initially found to be too low, a shut-off valve on the carbon dioxide cylinder is opened and the whole system is pressurised to an adequate working pressure P1 after which the shut-off valve is closed and the following procedure is the same as has already been described.

When the measurement has been completed, the beer in the tube 9 may be forced back into the keg by returning the valves to their starting positions so that the tube 9 is subjected to a pressure P1 or with the port 17 of the valve 18 closed, a beer drain tap 31 may be opened to drain the beer from the tube 9. The tap 31 may also be used for taking a sample of the beer at any time during the procedure to enable its condition to be seen and tasted.

In addition to its use for determining the amount of beer remaining in a keg returned by a publican to the brewery, the apparatus in accordance with the invention may equally well be used by publicans for stocktaking purposes. This is done regularly in many establishments.

When the apparatus is used for stocktaking, it will be used successively on a number of kegs. In order therefore to prevent cross-contamination between kegs, which would happen if the beer raised into the tub 9 were returned to the keg, the beer in the tube 9 is drained through the tap 31. To ensure that the beer is drained and not returned to the keg, a non-return valve may be fitted in the duct 4 in those cases where the apparatus is intended to be used for stocktaking.

WHAT WE CLAIM IS: 1. Apparatus for determining the depth of beer above the bottom of the spear in a keg of the kind described which is pressurised with carbon dioxide the apparatus comprising a fitting for attachment to the opening of the keg, the fitting having two fluid ducts through it, a first of the ducts leading to the inside of the spear and the second of the ducts leadng to the gas space outside the spear when the fitting is, in use, fitted to a keg, an upright tube or chamber, which has means for providing an indication when beer has risen to a predetermined level within it, the tube or chamber being connected to the first duct and being located above the fitting, a differential pressure gauge connected to the second duct and to the tube or chamber above the predetermined level to measure the pressure differential between the gas space and the tube or chamber while the tube or chamber is closed, and a valve device for venting the tube or chamber to allow the beer from the keg to be raised within the tube or chamber by the gas pressure in the keg to the predetermined level and then closing the tube or chamber again, whereby the differential pressure gauge provides an indication of the level of beer remaining in the keg above the bottom of the spear when the beer is held at the predetermined level and the valve device is closed.

2. Apparatus according to claim 1, in which the valve device comprises a manually operated cock or spool valve.

3. Apparatus according to claim 1, in which the valve device comprises a solenoid valve which is controlled by a level switch which is operated automatically when the beer reaches the predetermined level in the tube or chamber.

4. Apparatus according to claim 3, in which the level switch is magnetic and a magnetic float is provided in the tube or chamber, the float operating the magnetic switch when the beer has risen in the tube or chamber to the predetermined level.

5. Apparatus according to claim 4, in which there are two solenoid valves, the first one of the solenoid valves being three-way and having a first port connected to the differential pressure gauge, a second port connected to a throttled venting jet and a third port connected to a first port of the second solenoid valve which is also threeway, a second port of the second solenoid valve being closed and a third port of the second solenoid valve being connected to the tube or chamber above the predetermined levels, the solenoid valves being controlled by an electric circuit including the magnetic switch in such a way that when no power is supplied to either of the valves, in the first valve the first port is connected to the third port and in the second valve the first port is connected to the third port; when power is supplied to the circuit, but the level switch is not operated by the magnetic float, the second valve is unaffected, but in the first valve the first port is closed and the second port is connected to the third port and, when the magnetic switch is operated by the magnetic float, in the second valve, the third port is connected to the closed second port.

6. Apparatus according to any one of the preceding claims, in which a pressure gauge is connected to the second cut for providing an indication of the pressure in the gas space of the keg.

7. Apparatus according to claim 1, constructed and arranged to operate substantially as described with reference to the accompanying drawing.

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

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. of kegs. In order therefore to prevent cross-contamination between kegs, which would happen if the beer raised into the tub 9 were returned to the keg, the beer in the tube 9 is drained through the tap 31. To ensure that the beer is drained and not returned to the keg, a non-return valve may be fitted in the duct 4 in those cases where the apparatus is intended to be used for stocktaking. WHAT WE CLAIM IS:

1. Apparatus for determining the depth of beer above the bottom of the spear in a keg of the kind described which is pressurised with carbon dioxide the apparatus comprising a fitting for attachment to the opening of the keg, the fitting having two fluid ducts through it, a first of the ducts leading to the inside of the spear and the second of the ducts leadng to the gas space outside the spear when the fitting is, in use, fitted to a keg, an upright tube or chamber, which has means for providing an indication when beer has risen to a predetermined level within it, the tube or chamber being connected to the first duct and being located above the fitting, a differential pressure gauge connected to the second duct and to the tube or chamber above the predetermined level to measure the pressure differential between the gas space and the tube or chamber while the tube or chamber is closed, and a valve device for venting the tube or chamber to allow the beer from the keg to be raised within the tube or chamber by the gas pressure in the keg to the predetermined level and then closing the tube or chamber again, whereby the differential pressure gauge provides an indication of the level of beer remaining in the keg above the bottom of the spear when the beer is held at the predetermined level and the valve device is closed.

2. Apparatus according to claim 1, in which the valve device comprises a manually operated cock or spool valve.

3. Apparatus according to claim 1, in which the valve device comprises a solenoid valve which is controlled by a level switch which is operated automatically when the beer reaches the predetermined level in the tube or chamber.

4. Apparatus according to claim 3, in which the level switch is magnetic and a magnetic float is provided in the tube or chamber, the float operating the magnetic switch when the beer has risen in the tube or chamber to the predetermined level.

5. Apparatus according to claim 4, in which there are two solenoid valves, the first one of the solenoid valves being three-way and having a first port connected to the differential pressure gauge, a second port connected to a throttled venting jet and a third port connected to a first port of the second solenoid valve which is also threeway, a second port of the second solenoid valve being closed and a third port of the second solenoid valve being connected to the tube or chamber above the predetermined levels, the solenoid valves being controlled by an electric circuit including the magnetic switch in such a way that when no power is supplied to either of the valves, in the first valve the first port is connected to the third port and in the second valve the first port is connected to the third port; when power is supplied to the circuit, but the level switch is not operated by the magnetic float, the second valve is unaffected, but in the first valve the first port is closed and the second port is connected to the third port and, when the magnetic switch is operated by the magnetic float, in the second valve, the third port is connected to the closed second port.

6. Apparatus according to any one of the preceding claims, in which a pressure gauge is connected to the second cut for providing an indication of the pressure in the gas space of the keg.

7. Apparatus according to claim 1, constructed and arranged to operate substantially as described with reference to the accompanying drawing.