GB2498757A - Automatically priming soda recirculation pumps used in the dispense of post-mix carbonated beverages - Google Patents

Abstract

A beverage dispense system has a pump 2 for circulating liquid in a circuit including an accumulator vessel 1 for supplying liquid to an inlet of the pump 2 and for providing a head of liquid at the inlet such that the pump 2 can self-prime, preferably when a liquid level in the accumulator vessel 1 is at or above a pre-determined threshold value. Liquid withdrawn from the circuit via a dispense valve may be replaced from a liquid supply 8 so that the liquid level in the accumulator vessel 1 can be maintained at or above the pre-determined threshold value. The pump 2 may be switched off if the liquid level falls below the pre-determined threshold value to prevent the pump 2 running dry. Other aspects relate to a soda circuit for dispense of carbonated beverages, a method of dispensing a carbonated beverage, a method of priming pump and an accumulator vessel for supplying liquid to an inlet of a pump.

Description

BEVERAGE DISPENSE

This invention relates to beverage dispense and more especially to a means of automatically priming soda recirculation pumps used in the dispense of post mix carbonated beverages, both during commissioning and where an interruption of the water or CO2 gas supply may have resulted in the pump losing its prime.

In order to present draught post mix beverages to the customer at an acceptable temperature it is necessary to minimise the effect of ambient temperature on chilled carbonated water (soda) after it has left the beverage cooler and before it is mixed with a flavour syrup at the point of dispense. Where an over-counter dispenser or a cooler in close proximity to the dispense point is employed it is often only necessary to ensure that adequate insulation is provided for the product lines or to re-circulate chilled water alongside them to minimise heat transfer from the ambient surroundings.

Increasingly, space constraints in serving areas have required that coolers and carbonators are located remotely froni the dispense location and this has resulted in long pipe runs for transporting chilled carbonated water and syrup to the dispense point. Under these circumstances, the addition of insulation even when combined with re-circulated chilled water is generally inadequate to prevent warming of the carbonated water to the point of being unacceptable when dispensed as part of a post mix beverage. 4.5°C is generally accepted as the upper temperature limit for a post mix beverage in the cup and exceeding this figure not only reduces the consumer's satisfaction, it also results in excess foaming with a consequent loss of carbonation.

In order to overcome the problems described above it has become common practice to re-circulate the carbonated water which is to become a component of the dispensed beverage, between the cooler and the dispense valve. On returning to the cooler the carbonated xvater is re-chilled by passing through a cooling coil and may also be re-carbonated before being pumped back to the dispense head.

A range of pump types is employed for carbonated water recirculation, i.e. positive displacement, centrifugal or turbine but in all cases it is highly undesirable to allow them to run dry as this will result in poor dispense quality and eventually a noisy or damaged pump. Positive displacement pumps employing carbon vanes are particularly susceptible to damage from dry running and can contaminate thc system with carbon debris upon failure.

The present invention has been made from a consideration of the foregoing.

According to one aspect of the present invention, there is provided an accumulator vessel for supplying liquid to an inlet of a pump and for providing a head of liquid at the inlet such that the pump can self-prime.

It niay be that the pump can self-prime when a liquid level in the accuniulator vessel is at or above a pre-determined threshold value. It may be that the pump is switched off if the liquid level falls below the pre-determined thrcshold value to prevent the pump running dry.

The pump may be configured to circulate liquid around a circuit that includes the accumulator vessel. It may be that liquid can be withdrawn from the circuit and replaced from a liquid supply so that the liquid level in the accumulator vessel can be maintained at or above the pre-determined threshold value. It may be that the pump is switched-off if the liquid supply is unable to replace liquid withdrawn from the circuit and the liquid level falls below the pre-determined threshold value.

In one preferred embodiment, a controller may be provided for controlling operation of the pump according to the condition of the accumulator vessel and the liquid supply. For example, the controller may be configured to receive information relating to the liquid level in the accumulator vesscl and the availability of liquid from the liquid supply and to control operation of the pump in response thereto.

In one preferred embodiment, a low level liquid sensor may be operable to signal to the controller when thc liquid level in the accumulator vessel falls below the pre-determined threshold value and a liquid supply sensor may be operable to signal to the controller when liquid from the liquid supply is not available. A further high level liquid sensor may be provided to signal to the controller when the liquid level in the accumulator vessel reaches a pre-determined upper level higher than the pre-determined threshold value.

The controller may be operable to switch the pump off in response to signals from the low level liquid sensor and liquid supply sensor to prevent the pump running dry if liquid withdrawn from the circuit is not replaced by liquid from the liquid supply.

The controller may be operable to switch the pump on in response to signals from the high level sensor and liquid supply sensor indicating there is a positive head of liquid in the accumulator vessel to self-prime the pump and there is an available liquid supply to replace liquid withdrawn from the circuit.

It may be that the accumulator vessel includes a relief valve for releasing an accumulation of gas in a headspace of the accumulator vessel. The controller may be operable to open the relief valve in response to the low level sensor providing a signal that the liquid level in the accumulator vessel has fallen below the pre-determined threshold value when liquid is available from the liquid supply.

In this way, the pump may continue to operate while gas that has accumulated in the accumulator vessel to lower the liquid level in the accumulator vessel is vented allowing the liquid level in the accumulator vessel to rise as liquid is introduced into the circuit to replace the vented gas.

The relief valve may remain open until the high level sensor provides a signal to the controller that the liquid level in the accumulator vessel has risen to the upper level.

Alternatively or additionally, the relief valve may close automatically after a pre-set interval of time. This may prevent the relief valve remaining open if the liquid level does not reach the upper level for any reason so as to prevent uncontrolled loss of gas.

It may be that the invention has application for the dispense of beverages, and in particular post-mix beverages of the type in which water, especially carbonated water, is mixed with a flavoured syrup or other suitable concentrate to produce a beverage such as a cola.

Thus, the invention can provide a means of enabling a carbonated water re-circulation pump to self prime either during commissioning or after the pump loses its prime during operation, for instance, following an interruption of the incoming water supply, exhaustion of the CO2 gas supply or exceeding the carbonator output capacity by dispensing high volumes of drinks.

Post mix soft drink dispense systems are known in which mains water and a carbonating gas such as carbon dioxide (C02) are combined to form carbonated water, often known as soda', which is supplied to a dispense valve in a serving location together with the flavoured syrup to form the carbonated beverage. The system generally employs a soda circuit and the main elements can include:- * A carbonator into which mains water is pumped at high pressure into an atmosphere of CO2 to form carbonated water (soda).

* A cooler, usually comprising a water bath in which an ice bank is formed on the evaporator of a refrigeration system. Product coils may be immersed in the chilled water to cool soda and syrup passing through them. The chilled water may be agitated to improve heat transfer.

* A dispense valve(s) which combines the soda and syrup in a predefined ratio on demand.

* A pump to re-circulate soda between the cooler and the dispense valve(s) via insulated tubes known as a python'. The python may also include product lines for syrup.

The main elcments may be separate units or the cooler, carbonator and rc-circulation pump may be combined into one soda circuit'. The carbonator tank may be at least partially submerged in the chilled water of the cooler. Such an arrangement would feed pre-chillcd water into the carbonator and would be described as a cold carbonation system. Where the carbonator is remote from the cooler, it is normally fed with un-chilled water and known as an ambient carbonator'.

In accordance with a preferred application of the invention to such systems, the soda circuit is provided with an accumulator vessel to provide a head of carbonated water at the inlet to the pump whereby the pump can self-prime. Operation of the pump circulating the carbonated water may be controlled in response to the condition of the accumulator vessel and the carbonator supplying carbonated water to the circuit to prevent the pump running dry.

Thus, it may be that the pump is switched-off if carbonated water withdrawn from the circuit via the dispense valve(s) is not replaced by the carbonator and the liquid level in the accumulator vessel falls below a pre-determined threshold value corresponding to a minimum head of carbonated water required for the self-priming function of the pump.

In one preferred embodiment, a controller for controlling operation of the pump according to the condition of the accumulator vessel and the carbonator supplying the carbonated water to the circuit may be configured to receive information relating to the liquid level in the accumulator vessel and the availability of carbonated water from the carbonator and to control operation of the pump in response thereto.

In one preferred embodiment, a low level liquid sensor may be operable to signal to the controller when thc liquid lcvel in the accumulator vessel falls below the pre-determined threshold value and a liquid supply sensor may be operable to signal to the controller when carbonated water from the carbonator is not available. A further high level liquid scnsor may be provided to signal to the controller when the liquid level in the accumulator vessel reaches a pre-determined upper level higher than the pre-deterniined threshold value.

The controller may be operable to switch the pump off in response to signals from the low level liquid sensor and carbonated water sensor to prevent the pump running dry if carbonated water withdrawn from the circuit is not replaced by the carbonator. The controller may be operable to switch the pump on in response to signals from the high level sensor and liquid supply sensor indicating there is a positive head of liquid in the accumulator vessel to self-prime the pump and there is an available supply of carbonated water from the carbonator to replace carbonated water withdrawn from the circuit.

It may be that the accumulator vessel includes a relief valve for releasing an accumulation of carbonating gas in a headspace of the accumulator vessel. The controller may be operable to open the relief valve in response to the low level sensor providing a signal that the liquid level in the accumulator vessel has fallen below the pre-determined threshold value when carbonated water is available from the carbonator.

In this way, carbonating gas that has accumulated in the accumulator vessel to lower the liquid level in the accumulator vessel is vented allowing the liquid level in the accumulator vessel to rise as carbonated water is introduced into the circuit to replace the vented gas.

The relief valve may remain open until the high level sensor provides a signal to the controller that the liquid level in the accumulator vessel has risen to the upper level.

Alternatively or additionally, the relief valve may close automatically after a pre-set interval of time. This may prevent the relief valve remaining open if the liquid level does not reach the upper level for any reason so as to prevent uncontrolled loss of carbonating gas.

According to another aspect of the present invention, there is provided a beverage dispense system having a pump for circulating liquid in a circuit including a dispense valve and an accumulator vessel for supplying liquid to an inlet of the pump and for providing a head of liquid at the inlet such that the pump can self-prime. This aspect of the invention may include any of the features described in connection with the preceding aspect(s) of the invention.

According to still another aspect of the present invention, there is provided in or for a soda circuit for dispense of carbonated beverages by mixing carbonated water with a flavoured syrup at a dispense valve, a pump for circulating carbonated water around the circuit, and an accumulator vessel for providing a head of carbonated water at an inlet of the pump for priming the pump. This aspect of the invention may include any of the features described in connection with thc preceding aspect(s) of the invention.

According to yet another aspect of the present invention, there is provided a method of priming a pump including providing a pump having an inlet and an outlet and arranging an accumulator vessel to provide a head of liquid at the inlet of the pump to prime the pump. This aspect of the invention may include any of the features described in connection with the preceding aspect(s) of the invention.

According to still yet another aspect of the present invention, there is provided a method of dispensing a carbonated beverage including providing a source of carbonated water and a source of flavoured syrup, providing a dispense valve for combining carbonated water and flavoured syrup in a desired ratio for dispense of a carbonated beverage, re-circulating the carbonated water in a circuit including connections to the dispense valve and the source of carbonated water by means of a pump, and providing an accumulator vessel for carbonated water to provide a head of carbonated water at an inlet of the pump to prime the pump. This aspect of the invention may include any of the features described in connection with the preceding aspect(s) of the invention.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawing wherein Figure 1 depicts a soda circuit embodying the invention Figure 1 depicts a soda circuit embodying the invention wherein an accumulator vessel (1) is provided between a carbonator (not shown) and a soda re-circulation pump (2). The accumulator vessel (1) provides a chamber or reservoir for the soda.

The carbonator may be of any suitable type known to those skilled in the art for carbonating still water, for example mains cold water, with a carbonating gas, for example carbon dioxide, in a tank to provide a supply of carbonated water. The pump (2) may be a single speed pump, twin or other multi-speed pump or a variable speed pump. The pump may be of any suitable type including but not limited to centrifugal and turbine pumps although othcr pumps such as positive displacement pumps may be used.

The accumulator vessel (1) is located as close as possible to the pump (2) and is arranged such that, when thc liquid level within the accumulator vessel (1) is at or above a pre-determined lower threshold value, the pump (2) will self prime. Such arrangement will depend on the type of pump (2) employed. In this embodiment, a high level probe (1 Ia) and a low level probe (1 Ib) are provided. The lower threshold value is set by the low level probe (I Ib) and is such that, when the liquid level in the accumulator vessel (1) is below the low level probe (11 b), the pump (2) can no longer self-prime. An upper threshold value of the liquid level is set by the high level probe (1 la) for a purpose described later.

In a normal mode of operation, the pump (2) may be switched-on via a control unit (not shown) to circulate soda around the soda circuit when the level of soda in the

S

accumulator vessel (1) is above the lcvel of the low level probe (1 ib) and more preferably when the level of soda is at the level of the lugh level probe (11 a) whereby a positive head of soda is provided at the inlet of the pump (2) to self-prime the pump (2).

Soda withdrawn from the accumulator vessel (1) by the pump (2) via a suction tube (3) connected to the pump inlet flows from the pump (2) to a dispense valve (not shown) via a supply line (4). The dispensc valve may be connected to at least one source of concentrate such as a flavoured syrup for mixing with the soda in a desired ratio to produce a carbonated beverage such as a cola. The dispense valve may be provided by a hand held dispenser, sometimes called a bar gun, or it may be provided by a fixed dispenser, sometimes called an over counter or countertop dispenser. The dispenser may comprise a dispense head having one or more dispense valves. Such dispensers and dispense valves are well known to those skilled in the art and are not described further herein.

Soda which is not dispensed at the dispense valve is returned to the accumulator vessel (I) for re-circulation. In this cmbodiment, the soda flows from the dispense valve to a cooler (not shown) in a return line (5) where it may optionally pass through a cooling coil (6) within the cooler to maintain the correct temperature for dispense of carbonated beverages and then returns to the accumulator vcssel (1) via an inlet tube (7). The cooler may bc of any suitable type known to those skilled in the art and may comprise an ice bank cooler although this is not essential and other types of cooler may be employed.

Suction tube (3) extends towards the bottom of accumulator vessel (1) to draw soda from an area of minimum turbulence while inlet tube (7) is located close to the upper end of the accumulator vessel (1) in order to assist recombining of any CO2 in the headspace of the accumulator vessel (1) with the soda in the accumulator vessel (1).

During beverage dispense, soda drawn off via the dispense valve is replaced from the carbonator via a feed tube () and optionally a cooling coil (9) located in the cooler so that the soda circulating in the soda circuit is not warmed to any appreciable extent by the addition of soda from the carbonator. The carbonator may also be located wholly or partially in the cooler. The pressure of carbonating gas in the headspace of the carbonator may be such that soda withdrawn from the soda circuit via the dispense valve is automatically replaced by soda from the carbonator when there is a volume of soda available in the carbonator.

A liquid sensor (10) is located within the feed tube (8) to detect the presence of soda iii the feed tube (8) and level probes (11 a) and (11 b) are located at the upper end of the accumulator vessel (I) to detect the upper and lower liquid levels respectively.

The sensor (10) and level probes (1 Ia) and (1 lb) may respond to resistance, capacitance or any other suitable parameter or characteristic of carbonated water so as to distinguish between the presence or absence of liquid.

It during the normal mode of operation, there is an accumulation of gas in the headspace of the accumulator vessel (1) to the point where the liquid level falls below the low level probe (11 b), for instance, as a result of CO2 breakout', the control unit (not shown) responds to an appropriate input from the low level probe (1 lb) by opening a solenoid vent valve (12) to cxhaust gas from the headspace and allow the liquid volume to be made up from the carbonator via the feed tube (8) and inlet tube (7). The solenoid valve (12) may incorporate a restrictor to control the rate of gas flow in order to prevent further breakout in the accumulator vessel (I).

As gas is vented from the headspace, the liquid level rises to the point where it reaches the high level probe (11 a) and the control unit responds to an appropriate input from the high level probe (11 a) by closing the solenoid valve (12). As long as the liquid sensor (10) detects the presence of liquid in the feed tube (8), the venting/fill cycle of the accumulator vessel (1) will be repeated as required and the pump (2) will be allowed to run continuously or as required. Although the solenoid valve (12) is closed when the liquid level reaches the upper level probe (11 a), the liquid level may rise above the probe (Ila) if, for example, CO2 in the headspace is re-absorbed by liquid in the accumulator vessel (1) and replaced by liquid from the carbonator. The accumulator vessel (1) may be located wholly or partially within the cooler which may assist re-absorption of CO2 in the headspace. Alternatively, the accumulator vessel (1) may be insulated to reduce heat transfer with the environment.

If, during the normal mode of operation, the carbonator fails to make up the volume of soda dispensed via the dispense valve, the liquid level will fall in the accumulator vessel (1) and the liquid sensor (10) will sense the absence of liquid in the feed tube (8) and provide an appropriate input to the control unit (not shown) whereupon the control unit disables the automatic opening of the solenoid valve (12) to prevent wastage of gas. The effectiveness of the liquid sensor (10) may be enhanced by mounting the sensor (10) at the top of a tube loop or header arrangement just before the cooler.

If the liquid level in accumulator vessel (1) continues to fall to below the low level probe (I Ib), the control unit responds to the combined inputs from the low level probe (11 b) and the liquid sensor (10) to interrupt the power supply to the pump (2) in order to prevent possible dry running if dispense of beverages continues to exhaust the soda reserve in the accumulator vessel (1).

If flow of carbonated water from the carbonator resumes, the liquid sensor 10 detects the presence of liquid in the feed tube 8 and the control unit responds to an appropriate input from the sensor 10 to re-enable the venting/fill cycle of the accumulator vessel (1) by nieans of the solenoid valve (12) in response to input from the level probes (ila) and (lib).

When the liquid level in the accumulator vessel (1) reaches the high level probe (11 a) there will be a positive head of liquid at the pump inlet sufficient for the self-priming function and the control unit responds to an appropriate input from the high level probe (ha) to re-establish power to the pump (2) allowing it to self-prime and return to the normal re-circulation mode of operation.

If the system has been drained by continued dispense of beverage while the power supply to the pump (2) is interrupted, restarting the pump (2) may return quantities of gas to the accumulator vessel (1). Some of this gas may be combined into the soda with excess being vented by the cycling of the solenoid valve (12) as described above.

As long as the liquid sensor (10) detects the presence of liquid in the feed tube (8), the control unit allows the liquid level in the accumulator vessel (1) to be controlled by the level probes (11 a) and (1 ib) in conjunction with the solenoid valve (12) and power to the pump (2) will be maintained.

To prevent wastage or excess build up in confined spaces of CO2 gas, it may be desirable to provide a timer function within the control unit to limit the maximum period for which the solenoid (12) is allowed to remain open without the high level probe (1 Ia) detecting the presence of liquid in the accumulator vessel (1), for example by virtue of a water supply failure or a control malfunction. Such a timing function may additionally require a manual re-set, with or without a visual or audible status indication as a further safety feature.

As will be appreciated from the foregoing description of an exemplary embodiment, the provision of the accumulator vessel at the pump inlet has a number of benefits and may provide one or more of the following functions:- * Create a positive head of water to the pump inlet * Prevent CO2 gas intake to the pump when the liquid level falls below a pre-determined point * Collect CO2 gas at a point where it can be actively managed * Re-absorb CO2 gas into the water within the accumulator vessel (enhanced by cold surfaces) * Route excess CO2 gas to a vcnt valve * Accept inlet and outlet ports for system connection Although the operation of the auto priming function has been described above as a remedy during a normal mode of operation, it will be appreciated, however, that the process would operate equally effectively when commissioning a system and filling it from a dry condition.

It will be further appreciated that many options exist for configuring a dispense system and that the auto prime feature is equally suitable for both cold and ambient carbonation systems.

Such applications may rcquirc additional features such as insulation or chilling of the accumulator vessel (1) and/or, for example, time delays or multiple inputs from the liquid sensor (10) or level probes (1 Ia) and (1 Ib) before initiating an output from the control unit iii order to prevent short cycling.

While in the exemplary embodiment, invention has been described for a soda circuit, it will be understood that we do not intend the invention to be limited to such application and that the invention may have wider application not only in the field of beverage dispense but in other fields where it is desirable to control operation of a pump to prevent the pump running dry. For example, in the field of beverage dispense, the invention may have application where a pump is employed to circulate still water in a post-mix soft drink dispense system or where a pump is employed to circulate beer, lager or cider in an alcoholic dispense system. In post mix soft drink dispense systems, carbonated water (soda) and still water may be referred to as diluents for mixing with a concentrate (flavoured syrup) to produce carbonated or still beverages. In these systems carbonated water and still water may also be dispensed without mixing with concentrate.