DE29808343U1 - Valve seat for bottom valves - Google Patents

Description

7 May 1998

SchuF-Chemieventile Vertriebs-GmbH & Co. KG 65931 Frankfurt/Main-Sindlingen

Valve seat for bottom valves

This innovation relates to the drain valves in container bottom openings, especially in the pharmaceutical industry, biochemistry or genetics. The containers used here are enamelled and must be completely cleaned after a production process before another production process can begin. If this cannot be done without removing the bottom valve, the effort of completely removing it must be accepted.

The known bottom valves have a valve seat with an annular flange part, which is attached in a suitable manner to the bottom surface of the container or to its opening nozzle, and a cylinder section which projects into the bottom opening or the container nozzle and fills its interior. Their surface which comes into contact with the product is made of PTFE; they can be turned solidly from this material. If the valve has to be "fire-safe", ie must still close tightly in the event of a fire, the valve seat consists of a stainless steel core and the cylinder section and at least part of the flange part is PTFE-coated. _r -

If a complete cleaning is not possible without removing the entire

If the valve is to be operated correctly, the cylinder section must fill the space enclosed by the container bottom opening without any gaps.

With enamelled containers, it is not possible to achieve the geometry and dimensions of the bottom opening so precisely that the cylinder section of the valve seat can be inserted without play. The enamel coating prevents the bottom opening from having an exact inner diameter and precise roundness. In practice, this means that gaps remain between the inner surface of the container bottom opening and the outer surface of the valve seat cylinder section, into which the products can penetrate and which cannot remain.

An attempt is made to remedy the situation by providing the customer with the valves with an oversize cylinder section of the valve seat and then turning the cylinder section to fit himself after measuring the opening of the container bottom. Apart from the double machining effort, this method also makes it possible to

However, this does not mean that the gap caused by the roundness of the floor opening is eliminated. I

A known bottom valve of the type in question has a seat on the outside of whose cylinder section one or several narrow circumferential lips are formed, one above the other. However, these only result in linear contact with the inner surface of the bottom opening, which does not ensure a very reliable seal, particularly because of the low elasticity of PTFE.

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The basic idea behind this innovation is to improve the sealing of the annular gap between the outer surface of the valve seat cylinder section and the inner surface of the container bottom opening by designing an area of the outer surface of the valve seat cylinder section so that it can be subjected to external pressure, which can be done by integrating an elastic ring element or by applying pressure. The possible solutions are specified in detail in the protection claims.

The innovation is explained further below by describing two examples of implementation based on the attached drawings. It shows:

Fig. 1 the valve seat of a container bottom valve with elastic ring insert;

Fig. 2 the valve seat of a container bottom valve with

pressurizable PTFE ring bandage.

The valve seat according to Fig. 1 consists of a cylinder section 1, which projects from below into the bottom opening of the container (not shown), and a flange part 2, with which it is attached in a suitable manner to the bottom of the container or to a container nozzle containing the outlet. The closing element of the valve, also not shown, in the form of a valve disk, for example, rests in the closed state on the frustoconical seat surface 3, which is formed on the upper inner edge of the cylinder section 1.

The cylinder section 1 and a large area of the flange part 2 are surrounded by a PTFE casing 5. In the metal core of the cylinder section 1, in the outer surface near the upper edge, an elastic ring insert 8 is inserted into an annular groove, which can pressurize the PTFE casing 5 outwards. The insert 8, e.g. a spring or a soft seal, is attached before the casing 5 is applied and causes the outer surface of the cylinder section 1 to be elastically compressed in its area. When inserted into the bottom opening of the container, a flat seal is created that reliably seals off the gaps below.

In the embodiment according to Fig. 2, the PTFE casing 5' is surrounded by a PTFE ring bandage 10. At least one pressurization channel 12 leads into the space between the casing 5 and the ring bandage, which runs at a circumferential point through the flange part 2' and the metal core 6'. This bandage can be brought into a reliably sealing position on the inner surface of the container bottom opening by applying pressure.

A piece of hose can be used as a bandage, which is glued around the PTFE casing 5' of the cylinder section 1'. The pressurized gas can be air or nitrogen. The pressurization channel 12 is controlled by a check valve 14, which maintains this pressure after the pressure has been applied and allows the pressure source to be removed. In particular, the check valve prevents the liquid in the container from

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Pressurized products escape to the outside if the PTFE sheath 5' or the PTFE ring bandage 10 is damaged or melted by fire, or if the ring bandage 10 leaks or bursts.

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Claims (4)

7 May 1998 Protection claims 1. Valve seat for container bottom valves with a cylinder section (1, l')f protruding into the bottom opening of the container, which is provided on all sides with a PTFE coating (5, 5'), characterized in that at least one flat partial area of the outer surface of the cylinder section can be pressed elastically against the inner surface of the container bottom opening. 2. Valve seat body according to claim 1, characterized in that an elastic ring insert (8) is provided between the outer surface of the core (6) of the cylinder section (1) and the PTFE casing (5) which acts radially outward on the latter (Fig. 1). 3. Valve seat according to claim 1, characterized in that the outer surface of the PTFE casing (5') is surrounded by an annular bandage (10) also made of PTFE and the space between this and the casing can be pressurized by means of a compressed gas. 4. Valve seat according to claim 3, characterized in that the channel (12) for the pressurization runs through the cylinder section of the valve seat and a check valve (14) is provided in it.