FI70544B - NEDISNINGSBEKAEMPNINGSAPPARATUR FOER LUFTKUDDEFARKOST - Google Patents

Description

70544 -

Hovercraft anti-freeze equipment Nedisningsbekämpningsapparatur för luftkuddefarkost

The invention relates to an antifreeze unit for air-cushion vessels in which air is led into the cushions directly through the bottom of the hull 5 using a passageway »directed completely or partially towards the base. Such a method is used in relatively slow and simple hovercraft. The velocity of the air in the passageway is then considerably high, and when the air jet encounters a passage formed by water or a snow-covered ice surface, a strong splash of water or snow trapping in the cushion space occurs. This in turn causes harmful freezing on the bottom surface of the vessel. In this case, m.m. the carrying capacity of the vessel decreases.

In high-speed vessels, efforts have been made to improve stability by differential pressure of 15 compartmentalized cushions or to reduce air leakage by so-called air curtain effect or to utilize dynamic air pressure, after the fan with a sprayer.c This requires branching horizontally to different compartments or hull edges. Examples of this can be found in patent publications SE 301 090, POT 81/02352, DE 2 102 925, DE 2 557 860, US 3 662 852, US 4 042 060 and GB 1 227 882. All of these are characterized by the fact that the air flow reversal horizontal occurs either in the ducts inside the hull or in a separate rigid duct system installed under the hull. The disadvantage of these arrangements is that the system is complicated and expensive and prone to freezing if the vessel is submerged. At least it is not suitable for retrofitting to a finished ship, because rigid structures under the hull reduce the ship's ground clearance. Pa-30 GB 1 052 851 has a large flexible membrane under the hull which, due to its flexibility, may not reduce ground clearance as before. however, the function is not to control the air flow but to dampen shocks when passing over an uneven surface, and due to its large size 35 and flat shape, it is clearly different from the structure of the present invention.

2 70544

The invention prevents the air jet blowing through the base from facing the running surface perpendicularly. This is achieved by placing a film in front of the shower that turns the shower away from the vertical direction. The air jet thus mixes only slightly with the air space and no longer encounters the vehicle at high speed. This significantly reduces water splashing, snow trapping and susceptibility to freezing. The features of the invention are defined in claim 1. It is characterized in particular that the films are bent in a TJ or arc shape, in which case horizontal channels 8 are created between the films and the body.

The above-mentioned membrane to be placed in the path of the air flow, of course, increases the flow resistance which the fan must overcome and thus causes a loss of energy. Losses can be limited by appropriate sizing. In addition, as a further development of the invention, a partially air-permeable film can be used to reduce losses. Part of the air then enters, at a reduced speed, directly downwards, whereby, of course, the air resistance p ·? erier.es compared to the use of a dense membrane. The characteristics of this further development are defined in claim 2.

The invention will now be described in more detail, by way of example, with reference to the following figures:

Eig.l Airbag] door cross section. In this application, the air cushions have a duct 5 in the central area of the vessel and a duct 6 close to the edge, above the fingers of the hem.

Fig. Fig. A-section A-A when the horizontal channel 8 is one-piece.

Fig.3 "" "" "" "two-time.

Eig.4 "» «B-B w" «" * »

Fig. 5 "" view CC "" "" "" Fig. 1 shows the hull 1 of the vessel, the upper part 2 of the skirt, the a-part 3 of the skirt 3 »the cushion space 4 and the air duct ducts 5 and 6. so-called fingers, the transverse parts of which are sealed against each other due to internal pressure.The inlet channels 35 may be of type 5 or 6 or both, for example one pair 5 and 6 near the bow and the other pair close to the stern.

3 70544

According to the invention, U-shaped bent films 7 are suspended under the inlet channels 5 and 6. The films can be one or more side by side under the same inlet channel. This creates horizontal channels between the membranes and the bottom of the body 8.

In the embodiment according to Fig. 2, there is one membrane 7 below the inlet duct. This membrane forces the air jet coming from above to be divided in the duct 8 into two horizontal jets.

In the kig.3tn application, the horizontal channel 8 below the inlet is divided in half. ” This has the advantage that according to the flow laws, the air jet coming from the duct into the cushion space slows down much faster, reducing splashing and drifting. The channel 8 can be divided into several parts.

In the embodiment of Fig.4, the inlet is located above the fingers of the hem. In this case, of course, it is necessary to divide the channel 8 in such a way that each finger directly below the inlet even receives at least one own subchannel 8.

The ducts 8 must be dimensioned so long that the air jet bends sufficiently away from the vertical. Of course, unnecessary lengths must also be avoided. With model tests 20, a suitable dimensioning can be efficiently found.

In order to limit the flow resistance and the load on the fan, the total outlet cross-sectional area of the ducts 8 must be dimensioned large enough, i.e. approximately equal to or larger than the corresponding inlet duct 5 or 6.

The flow resistance is also reduced if an air-permeable substance as defined in claim 2 is used as the film 7. Such a method also dampens the oscillation tendency of the membrane-black.

In the applications 30 shown, the ducts 8 and the membranes 7 acting as their walls are installed transversely to the direction of travel of the ship. » This has the advantage that the membrane does not easily grip the oncoming obstacles, but flexes in their path. Of course, if desired, they can be oriented in other ways.

In order for the film to be flexible in the way of obstacles, it is preferred that it is also flexible, e.g. rubber. This is also desirable because the membrane could be sufficiently flexible when the vessel 5 stops, causing the air cushion to deflate and the bottom of the vessel to lie directly against a hard surface.

The membranes can be attached to the bottom of the vessel either directly or by means of loops.

Instead of the U-shape, the films can of course also be bent into 10 softer arc shapes.

Claims (2)

70544 Pat ent t i skat suction set 1 · Anti-freeze equipment (7) for air-cushion vessels in which air is passed with its cushions (4) directly through the bottom of the body (1) with the passage channel (5) or 5 (6) directed completely or partially towards the undercarriage, and anti-freeze equipment (7) is mounted below the passage duct opening to turn the air jet to the side, characterized in that the control device (7) consists of one or more adjacent membranes bent in a U-shaped or arcuate shape to form a horizontal duct (8) preventing air jets from encountering the vessel directly. Apparatus according to claim 1, characterized in that the membranes (7) are perforated or otherwise limited in air permeability. 1 «Non-operating devices (7) for the purpose of the airfoil, with the aid of lightning rods (4) directly to the genome scraper (1) of the air conditioner channel (5) (7) are mounted under a genomic gaming channel with a view to the use of a side-by-side rig, with the use of an apparatus (7) with a view to the use of a property 25-fold of the ligand membrane, dande en vägrät kanal (8), vilken hindrar I luftsträlen frän att träffa rörelseunderlaget direkt. 2. Apparatus according to claim 1, comprising a membrane (7) per-30 forers or pairs of integrated air valves.