DESCRIPTION:

Field of the invention

The invention relates to a vacuum valve for connecting a vacuum hose to a vacuum-foil-enveloped vacuum space situated over a vacuum table or mold plate, which vacuum table or mold plate comprises a base having a sealing tape attached to the base in a closed circle, where the vacuum foil is present over the base and is stuck to the sealing tape, and where the vacuum space shut off from the environment in an airtight manner is situated between the vacuum foil and the base within the circle formed by the sealing tape, which vacuum valve comprises a first valve portion which is located outside the vacuum space and is provided with a connecting opening for the vacuum hose, as well as a second valve portion which is located inside the vacuum space and is provided with a suction opening, where a connecting channel is present between the connecting opening and the suction opening.

State of the art

A vacuum valve of this type is generally known. When the known vacuum valve is utilized on a vacuum table or mold plate, a hole is to be made in the vacuum foil subsequent to which on either side of the vacuum foil a portion of the vacuum valve is to be installed at the location of the hole. Subsequently, the two valve portions are to be connected together while the vacuum foil is clamped in between the two valve portions. A disadvantage of this known vacuum valve is the fact that always an opening is to be provided in the vacuum foil. Furthermore, there is a risk that the vacuum valve with the vacuum hose connected to it tips over as a result of which the vacuum foil may end up in front of the suction opening. As a result, the suction opening is shut off and the vacuum foil may show leakage as a result of the ambient air pressure. In order to exclude this risk, a person is actually to hold the vacuum valve during use. In a hot-air oven this is impossible. If during the heating up process in an oven there is a sudden vacuum loss or ventilation, the known vacuum valve will tip over inside the oven as a result of the heavy vacuum hose that is coupled to the valve. This is also the case in an autoclave (vacuum and pressure relieve vessel). For the hardening process of a product to be processed in an autoclave on the vacuum table or mold plate, the space in the autoclave is first evacuated during the start up so as to be ventilated afterwards, where over-pressure is created in the autoclave for exerting pressure on the vacuum foil and thus pressing away all air present underneath the vacuum foil. During the transition from evacuation to ventilation there is a chance for the known vacuum valve to tip over owing to the heavy vacuum hose, after which, when evacuation takes place anew, the vacuum foil ends up in the suction opening of the vacuum valve and shows a leak. There is also a chance of the vacuum foil being wrinkled when the two valve portions are being coupled, as a result of which no complete sealing is obtained and thus the hardening process cannot be commenced.

Summary of the invention

It is an object of the invention to provide a vacuum valve of the type defined in the opening paragraph where the disadvantages mentioned above do not occur during operation of the vacuum valve. To this end the vacuum valve according to the invention is characterized in that the vacuum valve comprises a planar foot element that has a planar bottom by which the foot element can be installed on the sealing tape and has a smooth top on which a further sealing tape can be installed to which the vacuum foil can be attached while the suction opening is located in the planar bottom, which vacuum valve further includes a connecting element connected to the foot element, which connecting element is provided with the connecting opening. Since the vacuum valve projects into the vacuum space between the base and the vacuum foil, there is no need to provide a hole in the vacuum foil. Neither is there a chance of the vacuum valve according to the invention tipping over, because it is installed on the sealing tape. Since the vacuum foil is not clamped between valve portions, there no risk of wrinkling either.

An embodiment of the vacuum valve according to the invention is characterized in that in the bottom of the foot element at least a single slot is provided extending from the suction opening. This minimizes the chance of the suction opening being shut off unintentionally by a loose component in the vacuum space.

A further embodiment of the vacuum valve according to the invention is characterized in that the connecting element has in addition to the connecting opening at least a single further connecting opening which is connected to the connecting opening through a further connecting channel. As a result, two or more vacuum valves can be coupled to each other in a simple manner without the need for a T-piece.

The invention likewise relates to a vacuum table or mold plate for manufacturing high-grade fiber- strengthened plastic objects, for example for aviation and space travel, comprising a base and a sealing tape attached to the base in a closed circle, as well as a vacuum foil present over the base and which is attached to the sealing tape, where a vacuum space shut off from the environment in an airtight manner is situated between the vacuum foil and the base within the circle formed by the sealing tape, which vacuum table or mold plate further includes a vacuum valve having a first valve portion which is located outside the vacuum space when operated on the vacuum table or mold plate and has a connecting opening, and a second valve portion which is located inside the vacuum space when operated on the vacuum table or mold plate and has a suction opening, where there is a connecting channel located between the connecting opening and suction opening.

As regards the vacuum table or mold plate, the invention is characterized in that the vacuum valve is located between the vacuum foil and the base, where the vacuum valve is installed on the sealing tape, and a further sealing tape whose tape ends adjoin the base-attached sealing tape is installed on the vacuum valve, while the vacuum foil is installed on the further sealing tape at the location of the vacuum valve. Brief description of the drawings

The invention will be further elucidated below relating to an example of embodiment of the vacuum table or mold plate and vacuum valve according to the invention shown in the appended drawings, in which:

Fig. 1 shows a perspective view of an embodiment of the vacuum table or mold plate according to the invention;

Fig. 2 shows a plan view of the vacuum table or mold plate shown in Fig. 1;

Fig. 3 shows a rear view of the vacuum table or mold plate shown in Fig. 1;

Fig. 4 shows a side view of the vacuum table or mold plate shown in Fig. 1; Fig. 5 shows a plan view of an embodiment of the vacuum valve;

Fig. 6 shows a side view of the vacuum valve shown in Fig. 5;

Fig. 7 shows a rear view of the vacuum valve shown in Fig. 5;

Fig. 8 shows a bottom view of the vacuum valve shown in Fig. 5;

Fig. 9 shows a sectional view of the vacuum valve along line A-A in Fig. 5; Fig. 10 shows a sectional view of the vacuum valve along line B-B in Fig. 5; and

Fig. 11 shows a sectional view of the vacuum valve along line C-C in Fig. 5. Detailed description of the drawings

Figs. 1 - 4 show an embodiment of the vacuum table or mold plate according to the invention in a perspective view and various other views. The vacuum table or mold plate 1 comprises a base 3 to which a double-sided adhesive tape 5 is attached along an uninterrupted circumferential line. In this example the line along which the sealing tape is present is a rectangle, but any form is possible. In this exmple the base is formed by a planar plate, but it may also be a curved surface. A vacuum foil is to be installed on the sealing tape, which foil is located within the circle formed by the sealing tape. This vacuum foil has been omitted in the drawing figures for clarity. Within the circle formed by the sealing tape there is a vacuum space in which the product 7 to be processed is present between this vacuum foil and the base, which vacuum space is shut off from the environment in an airtight manner.

For evacuating this space in this embodiment the vacuum table or mold plate is provided with two vacuum valves 9, but also one or more is a possibility, where they are connected to each other via a connecting line 11. A vacuum hose 13 emanating from a vacuum pump is connected to one of the vacuum valves. The vacuum valves are provided with connecting openings to which connecting nipples 15 can be connected or which can be shut off by means of caps 17 as desired.

The bottoms of the vacuum valves 9 are installed on the sealing tape 5. For rendering a closed circle again formed by the sealing tape, a segment of further sealing tape 19 is installed on the tops of the vacuum valves, which segment adjoins the two ends of the sealing tape.

Figs. 5 to 8 show an embodiment of the vacuum valve in various views and in the drawing figures 9 - 11 various sectional views of the vacuum valve are shown for clarity. The vacuum valve 9 comprises two valve portions of which during operation on the vacuum table or mold plate one valve portion is situated outside the vacuum space and has connecting openings 21 , and the other valve portion is situated inside the vacuum space and has a suction opening 23 which is connected through a connecting channel 25 to the connecting openings. The open end 26 of the connecting channel (see Fig. 9) is to be closed by a plug or cap. The vacuum valve comprises a planar foot element 27 which has a planar bottom 29 by which the foot element can be installed on the sealing tape, and a smooth top 31 on which the further sealing tape can be installed. The suction opening 23 is located in the planar bottom 29. The vacuum valve further includes a connecting element 33 connected to the foot element, which connecting element has the connecting openings 21. The connecting openings are in contact with each other (see Fig. 10) through further connecting channels. Thanks to the presence of these connecting openings, two or more vacuum valves can be coupled to each other in a simple manner without the need for T-pieces.

The bottom 29 of the foot element 27 has a plurality of slots 35 extending from the suction opening 23. These slots form channels located in the bottom of the foot element and having an open under side, as a result of which the chance of the suction opening being shut off unintentionally by for example a loose component in the vacuum space is strongly reduced.

Albeit the invention has been described in the foregoing with reference to the drawings, it should be observed that the invention is not by any manner or means restricted to the embodiment shown in the drawings. The invention also extends to all embodiments deviating from the embodiment shown in the drawings within the scope defined by the claims. For example, the foot element of the vacuum valve may also be arranged to be narrower, making the vacuum valve more suitable for being installed on a base having a curved surface. In that case there are preferably only two slots located in the under side of the foot element extending in longitudional direction of the foot element.