Tap
A nozzle (also beer tap ) is a shut-off valve for controlling the flow of fluid from a dispenser for beverage , a pipe , a beverage keg or other container. Other names - with some special construction forms - are: barrel tap, water tap (also water crane), beer tap, oil tap, grater (dialect: Bavarian ), change (beer tap for the wooden barrel).
Taps were traditionally designed as a plug valve , today mainly as a piston tap (piston tap ). The filling valve for petrol at petrol stations is also referred to as a tap . However, the way it works is different.
The peg or bung is a conical plug that was driven into the bunghole to close barrels. The bunghole was used to fill barrels. The tap can be knocked into the bunghole or into a separate tap hole .
In contrast to a drain valve , a "cock" is opened and closed within a maximum of a 1/4 turn by a tilting or rotating movement. With a valve, this usually takes several turns.
The tap possibly got its name from the design of the handle of the chick that was common in the past . The plug is the moving part of the closing valve, which fits precisely into the conical bung of the valve frame, which is hammered into the liquid container or is permanently mounted on the pipe system. There are two fundamentally different types of construction:
- the angled stopcock , where the flow of liquid exits through the cone that is open at the bottom. (In rare cases he rises in the same to exit the end of the handle).
- the passage valve , which has a separate outlet on the valve frame in relation to the bung.
In modern kegs, the tap is often screwed into the keg. Traditionally it was hit with the help of a hammer. This so-called barrel tapping is often carried out ceremonial at the opening of public festivals .
History of the tap
Taps in the shape of the classic conical tap, a simple valve with a conical closing mechanism, had been known since Roman times and were in use in various forms from the Middle Ages to the first half of the 19th century. They were used to shut off liquid lines on barrels, aquamanils (watering vessels) and water pipe systems. In archaeological research, the taps are distinguished on the basis of formal criteria of the frame (in the shape of a dolphin, horse or dog) and the handles called chicks (as a cock, bird, crown or three rings) and thus a chronological and regional breakdown is possible.
Philo of Byzantium described around 230 BC Reusable taps for tapping different types of wine. The stopcock of a lead water pipe comes from Xanten from the 2nd century AD. Another conical tap made of a copper alloy with remnants of a lead pipe connection is available from Cologne in Rome . The earliest medieval evidence comes from the 13th century . So far, however, only pictorial representations and written mentions are known from this time. Metal taps were in use at the latest around 1400 and date from the 15th and 16th centuries. Century and more recently in large numbers and various forms as archaeological finds .
In 1837 the first gate valve with screw spindle was patented in England , which in many applications replaced the classic conical valve .
Today's uses and shapes
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The tap is also still used in modern dispensing systems, as can be found in today's gastronomy . However, it is no longer thrown directly into the barrel, but is usually mounted on the counter on a dispensing column (often in the form of an attractively designed decorative column) and connected to the barrel via a hose .
A tap is generally designed so that it can be completely dismantled for cleaning. This is absolutely necessary because it comes into direct contact with the luxury or food beer or other beverages. Any deposits would lead to health and taste impairments in the long term. The choice of material is one of the decisive factors here.
In addition to the simple tap, which only interrupts the flow of drinks into the glass, there is now the so-called compensator tap . This differs from the normal tap in that it has a nozzle system inside, which makes it possible to draw a drink, especially beer, without foam. Dispensing systems equipped with these taps are operated at a higher pressure (> 1 bar ) than conventional systems (<0.7 bar). From the outside it differs through a small adjusting lever on the side, with which the flow cross-sections inside can be changed.
The quick tapping of acidic and sugary drinks such as cola and lemonades would not be possible without these taps.
A special tap is also used for tapping stout beers (e.g. Guinness beer ), which, in addition to nitrogen as a pressurized gas, is responsible for the special creamy foam.
According to the dispensing system regulation (which has since expired), only approved taps were allowed to be used in German gastronomy.
Others
The over-foamed or scraped off beer foam in draft beer is called a lick beer , which in draft beer systems is caught in a tub under the tap, usually covered with a perforated, grated or slotted plate. Corresponding collecting devices for over-foamed or dripping beer, sometimes only in the form of a collecting container set up below the tap, are also often found when drawing beer from kegs. Earlier the leak beer was often at a lower price to financially underprivileged customers served . Today the term is also used for stale, thin, stale or adulterated beer as well as for an inferior type of beer .
Trivia
The word Zapfenstreich (military: bar closings / commanded bed rest) is derived from the tap.
literature
For the cone cock in Roman times, in the Middle Ages and in the early modern period
- Max Kromer: Water in every citizen's house. The drinking water supply, historically traced and illustrated using the example of the former Free Imperial City of Ulm , Frankfurt / M. 1962
- Walter Drack : On the history of the faucet. The Roman water taps and medieval taps from Switzerland and the Principality of Liechtenstein. , Communications of the Antiquarian Society in Zurich 64, Zurich 1997, ISBN 3-85865-513-9 .
- Stefan Krabath: The high and late medieval non-ferrous metal finds north of the Alps. An archaeological-art-historical investigation into their production technology, functional and temporal determination. , International Archeology 63, Rahden / Westf. 2001, Vol. 1, 40-52 (Chapter 6.1.1.2. Cone Taps), ISBN 3-89646-335-7 .
Individual evidence
- ↑ Johannes Waechter: The change runs and runs and runs. sueddeutsche.de, September 15, 2013, accessed on September 20, 2014 .
- ↑ AMMER´S WIESNBIER (READ AND NOTE) SIGN. (PDF; 145 kB) (No longer available online.) Joseph AMMER eK , 2013, archived from the original on September 22, 2014 ; Retrieved September 20, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ see also: Zapfen (technology)
- ↑ Nick Eggers: Do you speak Hamburgisch? (395). In: Abendblatt.de . April 17, 2010, accessed September 26, 2016 .
