Fire extinguishers – Sprinkler heads
Reexamination Certificate
2000-02-04
2001-11-20
Morris, Lesley D. (Department: 3752)
Fire extinguishers
Sprinkler heads
C239S558000
Reexamination Certificate
active
06318474
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a spray head, preferably for extinguishing fire, comprising a frame, an inlet and a passage leading to at least one nozzle with an opening including a first boring and a second boring, the first boring comprising a first diameter and the second boring a second diameter. The spray head nozzle is, when driven, intended to provide mist, i.e. small droplets when a particular pressure is exerted in the nozzle.
Similar spray heads are known in the art. For example, U.S. Pat. No. 5,944,113 discloses such a spray head.
In order to be able to spray mist with small droplets from known nozzles, the known spray head nozzles comprise openings into which various mechanical obstacles are arranged. Such a mechanical obstacle may be, for example, a rotating body, a stationary particularly shaped locking part, a helical spring etc.
When similar obstacles are used a considerable drawback is that they reduce the efficiency of the spray head. This means that a fairly high effect is needed to provide a desired type of spray.
Said obstacles in the nozzles also mean that the structure of the nozzles and spray heads become fairly complicated. The nozzles are difficult to produce and they are supported in specific nozzle housings mounted into the frame of the spray head. Consequently the production costs of the spray head increase.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to a spray head which can be produced very economically and does not comprise said drawbacks and which despite the drawbacks is able to spray fine mist from its nozzle or nozzles.
In order to achieve said object the spray head of the invention is characterized in that the first boring has a diameter that is 0.1 to 0.9 times the diameter of the second boring, that the length of the first boring is 0.25 to 15 times the diameter of the first boring, and that the length of the second boring is approximately 0.25 to 15 times the diameter of the second boring.
According to a preferred embodiment the diameter of the first boring is approximately 0.3 to 5 mm. The diameter of the second boring is preferably not more than about 50 mm. As for the formation of mist a particularly advantageous effect is obtained by arranging the first boring at an angle in relation to the medium flow in the main channel of the nozzle. A wider angle generally provides mist with smaller droplets, i.e. a better result in view of the mist formation.
The invention is based on the astounding observation that mist including very small droplets can be produced without having to place mechanical obstacles into the nozzle
ozzles of the spray head, when the nozzles are dimensioned as indicated in the attached claims. In order to produce the mist, a high pressure is not necessarily needed but the mist can be produced with a relatively low pressure, typically from about 10 bar upwards. The medium is immediately composed of very small droplets as it flows out of the nozzle.
An essential advantage of the spray head is that it comprises a high efficiency, whereby a fairly low effect is sufficient for producing a mist-like spray with very small droplets. This means that a fire extinguishing installation provided with the spray heads of the invention may comprise a drive source and additional components which are smaller and considerably less expensive than the ones known. This is particularly important in surroundings where a limited and fairly minimal effect is available. Another essential advantage is that the construction of the spray head can be very simple. The number of components in the spray head can be drastically reduced. For example, in a sprinkler with a slidable spindle and a few nozzles and a heat-releasing ampoule, the number of components can be reduced from approximately 40 to 8 without having any negative effects on the function and safety of the spray head. In its simplest form the spray head may consist of only a single part. The structure of the spray head frame may be particularly simple and separate nozzles from the frame are not needed. The fact that no nozzles are needed means that the production costs for the spray head remain considerably lower than for the known spray heads providing mist.
REFERENCES:
patent: 2813753 (1957-11-01), Roberts
patent: 4032300 (1977-06-01), Parker et al.
patent: 4151958 (1979-05-01), Hofmann
patent: 5485961 (1996-01-01), Reitzig
patent: 5617922 (1997-04-01), Sundholm
patent: 5944113 (1999-08-01), Sundholm
patent: 19907355 (2000-09-01), None
patent: 2178342 (1987-02-01), None
patent: 9215370 (1992-09-01), None
patent: 9502433 (1995-01-01), None
patent: 9601666 (1996-01-01), None
patent: 9804322 (1998-02-01), None
Ladas & Parry
Morris Lesley D.
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