Patent Application
20090014075
The present invention relates to a dispenser tap, particularly of the type used in public houses to dispense beer or ale products.
Some beverage products (e.g stout) require the dispenser to include an agitating means to produce a foamy head as the beverage is dispensed. A usual way to achieve this is to use a creamer plate 14 (also known as a restrictor plate) that contains a plurality of fine holes 14a. Stout passes through the holes and gas (e.g. nitrogen) is encouraged out of solution to form tiny bubbles which comprise the head on the beverage.
A creamer plate 14 of the known type is simple and effective, however, it has several drawbacks. The main drawback is that over time the small holes 14a can become clogged with scale and other impurities from the beer delivery lines and from beverage that dries inside the dispensing nozzle outlet 12 when not in use.
Ideally, staff at the public house where the tap is installed will regularly clean the nozzle and creamer plate 14 by removal (the creamer plate is normally mounted in a threaded nozzle) and soaking overnight. Despite these relatively simple maintenance requirements, cleaning can be neglected and it is not uncommon for servicemen to be called out to fix a “faulty” dispenser, when all that is wrong is some scale built-up on the creamer plate.
Attempts have been made in the past to move the position of a conventional creamer plate to the “wet side” of the valve. For example, WO9837011 describes such an arrangement where all beer passing through the tap is agitated before it reaches the valve. This arrangement could be used with stout type beer but would still encounter clogging problems from impurities (it does, however, avoid the problem of dried beer deposits).
Also known to the hospitality trade is a dispenser tap more suitable for lager that does not include a creamer plate (because this would result in a glass full of foam and little or no actual liquid) in the main flow-line, but includes a secondary flow-line for a small portion of the liquid bound for the glass, that does include agitating means. This is simply an aid for the bar staff to deliver an aesthetically pleasing foam head to the lager. This is usually done by filling most of the glass with smoothly flowing liquid and then pressing a button on the tap to activate a brief squirt of agitated liquid through the secondary flow-line that provides a foamy head.
Such devices require some practice to use due to the timing of delivering a desirable head. Similar problems with cleaning of the extra flow channel agitating means can be experienced.
A prior art example that goes some way to providing an improved feature in dispenser taps is GB2225840. This construction includes a spiral groove in the end of the piston valve, with a seal upstream. A sloped side wall in the nozzle bore is such that when the seal lifts, beer flows into the grooves causing agitation until the valve withdraws fully, thereby allowing smooth flow. Careful control of the tap can allow the user to hold the dispenser in an agitated position to provide a foam head as desired.
GB2225840 has similar maintenance problems as described above, i.e the grooved end of the piston is in open air when not in use and thus can dry up and become clogged.
It is an object of the present invention to provide an improved dispenser tap that goes some way to alleviating the problems experienced in the prior art or at least provide an alternative.
In one broad aspect the present invention provides a dispenser including a main body and a bore at least partially therethrough with an inlet, an outlet and a piston moving therewithin from a first position when, in use, fluid flow between the inlet and the outlet is closed to a second position where fluid flow is open toward the outlet, the open fluid flow being turbulent by moving though a channel formed in the main body or the piston upstream of the outlet where it was closed in the first position.
In one form of the invention the channel is a tunnel bored into the main body or piston.
In a preferred form of the invention a third position of the piston allows fluid flow to be “fully open” and not turbulent relative to the second position.
In
Referring to
A second seal area is provided by a widened collar member 27 (wider than but adjacent to piston head 24) extending radially about the shaft of the piston 23. The second seal is an O-ring 26a around collar 27 and in contact with main body 20 at a second zone 28 of yet wider diameter than zone 25. Above zone 28 is a third zone 29 (referred to hereinafter) of yet wider bore diameter than zone 28. The subsequent zones provide a somewhat “stepped” appearance to the wall of main body 20 when viewed in cross section in the figures.
The end view section A-A shows the outlet for fluid through the dispenser completely closed.
Position B shows an intermediate stage where restricted (and hence turbulent) flow is allowed through the dispenser. Piston 23 is slightly withdrawn in position B.
Restricted flow is possible by virtue of a plurality of channels 30 formed longitudinally in the main body wall at zone 28, section B-B shows three evenly spaced semi-circular channels 30 or cut-outs where fluid can escape past collar 27 (with O-ring 26a). The size, shape and length of channels 30 can be varied (the size may be exaggerated in the drawing—in practice the channel will probably quite small) as appropriate to those skilled in the art. Generally the cross section area of the channels 30 would be only a fraction of the main bore diameters (e.g. less than 5%).
In position C the piston 23 is completely withdrawn into zone 29 that is substantially wider than collar 27. As such there is open and unrestricted flow through outlet 22. Section C-C shows the contrast of open flow to restricted flow through channels 30 shown in section B-B.
The intermediate flow stage B, through channels 30, replaces the creamer plate function known to the prior art. Moreover, this construction is completely flooded with fluid before and after use so there is no opportunity for beverage to dry and clog the agitating means (channels 30). Any debris within the system is adequately washed away when the dispenser is in the fully open position C.
It should be noted that piston head 24 with an O-ring seal 26 and zone 25 is not strictly necessary. In other words the “piston head” could be collar 27 alone, sealing within zone 28 in the closed position A. However, it is expected that over time channels 30 could wear away O-ring 26a and cause leakage. Therefore the piston head 24 as illustrated is provided because it operates at a different diameter to channels 30, avoiding wear.
When piston 23 begins to withdraw, flow through channels 30 is opened in position B (see end section view B-B). This is equivalent to the first embodiment of
Position C is a fully open flow mode past the stepped zones of main body 20 toward outlet 22.
As can be seen in position A, the channels 30 extend from a lower-most edge of piston head 24 to a length terminating before zone 25 widens to zone 29 (there is no need for second zone 28 in
Position C shows piston 23 withdrawn into zone 29 to open flow fully through the dispenser.
It will be apparent in
The reverse movement (C-B-A) closes the valve, while first going through a turbulent phase B.
In position A piston head 24 (shown with an O-ring 26) is sealing outlet 22 by being situated below (downstream) the link tunnels 34. As the piston withdraws the dispenser enters turbulent flow mode by allowing fluid to force through the restricted tunnels 34 when the piston head moves beyond the outlet of link tunnel 34 (position B) in zone 25.
In position C the piston head 24 has withdrawn into zone 29 for fully open flow. The flow through tunnels 34 is negligible when in position C.
It can be noted that a smaller diameter zone could be included with a corresponding sealing member at the distal end of piston 23 (with an appearance similar to
A fifth embodiment illustrated by
As usual, position A is fully closed. The piston head 24 is angled in a conical shape with sealing properties against a corresponding sloped surface of main body 20 toward outlet 22. In this embodiment there are not strictly any stepped “zones” as in
As piston 23 withdraws, flow is opened to outlet 22. In this case flow at position B is fully open to deliver fluid.
As piston 23 continues to withdraw it contacts an annular insert 36 with a central bore passage that prevents further upward movement of piston head 24. Insert 36 is located around the tubular wall of main body 20 and may have conically inward-sloped walls to conform and seal with an upper surface of piston head 24. Insert 36 would close flow through the dispenser completely, however, channels 35 in the upper surface 24a of piston head 24 (contacting insert 36) provide the requisite gap and allow restricted flow and turbulence to create foam in the beverage.
Alternatively, the upper surface 24a of piston head 24 could be smooth and channels 35 can be formed in the downstream wall of the insert 36. This achieves the same result of a restricted flow path when piston head 24 is withdrawn to its maximum extent and stopped by insert 36.
The sequence of flow of this fifth embodiment: closed, full, turbulent is more suited to certain stout ale products where the longer period of pouring (position C) is desired to be turbulent. When pouring comes to an end (i.e. glass is full), the process reverses so there is a brief period of full flow before closure (C-B-A).
Referring to position A, flow is closed as usual. Piston head 24 is sealed against outlet 22.
Position B is a fully open mode allowing fluid to pass smoothly toward the outlet 22.
As piston 23 withdraws it is stopped by insert 36 in the same way as
As in
Associated apparatus such as operating levers (to withdraw piston 23) have not been illustrated. A number of alternatives are possible, including electrical operating means to control withdrawal of the piston to specified dispensing presets.
Furthermore, it will be apparent to those skilled in the art that combinations and variations to the described concepts is possible, still within the scope of the present invention. For example, a ridge or protrusion from a wall of the piston could mate with a channel formed in the main body for additional sealing. This then opens the channel for turbulent flow only when the ridge of the piston withdraws sufficiently from the channel.
The manufacturing and materials techniques to implement the present invention are well established in the art. Components may be machined from stainless steel or plastics as appropriate. Satisfactory tolerances and clearances for “must-fit” parts are important to ensure efficient working of the piston within the main body.
It is preferable but not essential that the restrictive portion of the design be made from a hard material like stainless steel as opposed to plastic for a durable sharp edge to be maintained.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0414939.9 | Jul 2004 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB2005/002587 | 6/30/2005 | WO | 00 | 9/13/2007 |
