ENHANCED FIRE SAFETY VALVE

Technical area

The present invention relates to a tank bottom valve for a reactor, mixer or storage equipment having improved fire safety to reinforce its tightness in case of fire.

The invention relates more particularly to a bottom tank valve in which the seat on which the shutter is resting is covered with a fluoropolymer layer.

State of the art

In the field of reactor bottom valves for a reactor, mixer or storage equipment, the seat on which a shutter is resting is usually covered with a fluoropolymer layer which has the particular advantages of both resisting the products in contact, to be neutral in terms of chemical reactivity, to be easily cleaned and to have excellent sealing.

During very hot weather, especially in case of fire, it sometimes happens that this fluoropolymer layer deteriorates, for example by burning or melting. The shutter of the valve is then directly in contact with the seat material located under the fluoropolymer layer, usually stainless steel. This contact is not satisfactory from the point of view of the seal and dangerous liquids likely to be contained in the reactor can then flow through the valve, which represents serious dangers, especially for the environment. general and more specifically for security officers intervening to extinguish the fire. Especially since a possible Fire-Safe certification of the valve would prohibit this phenomenon.

The material of the shutter is then found directly in contact with the seat material located under the fluoropolymer layer. Again, this contact is unsatisfactory from the point of view of the seal and hazardous liquids can flow through the valve.

Description of the invention

The object of the present invention is therefore to overcome the disadvantages of the prior art by proposing a new valve with improved fire safety to strengthen its tightness in case of fire.

The objects assigned to the invention are achieved by means of a valve

comprising a body having a through passage and comprising a shutter movable between a first position in which it allows the flow of a product through the passage and a second position in which it interrupts the flow of the product, wherein opening of the through passage comprises a fluoropolymer coating which, under normal operating conditions, provides a seat between the body and the shutter when the latter is in its second position, characterized in that it comprises at the level of the opening of the passage through a sealing ring made of a non-metallic material resistant to high temperatures which, under normal operating conditions, is completely covered by the fluoropolymer coating, and which,in case of failure of the fluoropolymer coating, provides a seat between the body and the shutter and comes into contact with the shutter when the shutter is in its second position so as to interrupt the flow of the product through the through passage .

Thanks to the sealing ring made of a material resistant to creep and offering a satisfactory seal when in contact with stainless steel, alloy or enamel, the sealing ring interrupts the flow of the product through the valve when in its second position. Thus, in the closed position, the valve according to the invention remains tight during a fire or extreme heat conditions.

According to an exemplary implementation of the invention, the sealing ring withstands temperatures above 750 ° C.

According to another example of implementation of the invention, the sealing ring is made of graphite. Graphite, in addition to withstanding extremely high temperatures, has an excellent creep resistance effect which helps to seal the valve.

According to a further example of implementation of the invention, the sealing ring has a thickness of between 1 and 10 millimeters, preferably between 2 and 8 millimeters and more preferably between 3 and 5 millimeters. It resists without breaking thus to the pressure exerted by the shutter.

According to an exemplary implementation of the invention, the sealing ring has a smaller internal diameter than the opening of the through passage when it is considered without a fluoropolymer coating. The sealing ring is thus provided to ensure sealing of the valve with the shutter only when the fluoropolymer coating fails.

According to another example of implementation of the invention, the

Fluoropolymer coating is perfluoroalkoxy or polytetrafluoroethylene.

According to a further example of implementation of the invention, the shutter comprises an outer layer of enamel.

According to an alternative embodiment of the invention, the sealing ring is housed in a groove provided in the periphery of the opening of the through passage of the valve.

According to this variant, the groove may be provided so that the thickness of the fluoropolymer coating situated above the sealing ring is greater than that of the fluoropolymer coating located elsewhere on the body of the valve, preferably twice higher.

According to an alternative embodiment of the invention, the shutter is movable axially relative to the through passage so as to move away from and towards the opening of the through passage.

Brief description of the drawings

Other features and advantages of the present invention will appear more clearly on reading the description which follows, made with reference to the accompanying drawings, given by way of non-limiting examples, in which:

- Figure 1 is a partial view of a reactor, mixer or storage equipment equipped with a bottom of the tank valve according to the invention, with a cutaway cut at the valve;

- Figure 2 is a partial sectional view of a valve according to the invention equipped with a shutter with vertical displacement in the closed position, which valve is shown under normal conditions;

- Figure 3 is a partial sectional view of a valve according to the invention equipped with a shutter with vertical displacement in the closed position, which valve is shown under conditions where the fluoropolymer coating of the seat is faulty;

- Figure 4 is a partial sectional view of a valve according to the invention equipped with a shutter with vertical displacement in the closed position, which valve is shown in conditions where the fluoropolymer coating of the seat and the enamel coating Shutter, if present, are faulty;

FIG. 5 is a detailed view of the portion encircled in FIG. 2; and FIG. 6 is a detailed view of the portion encircled in FIG. 4.

Mode (s) of realization of the invention

The structurally and functionally identical elements present in several distinct figures are assigned a same numerical or alphanumeric reference.

The invention relates to a valve (1), or any other valve apparatus.

The valve (1) according to the invention is preferably designed to equip the bottom of a reactor vessel (2), mixer or storage equipment as shown in Figure 1, but it can be adapted to any type of container for which an improved fire safety is desired to reinforce its tightness in case of fire.

A valve (1) usually comprises a body (3) provided with a through passage (4) and a shutter (5) movable between a first position in which it allows the flow of a product through the through passage (4). ) and a second position in which it interrupts the flow of the product.

The body (3) of the valve (1) is usually made of carbon steel, stainless steel or alloy and optionally covered with an enamel coating or fluoropolymer in its inner part.

The opening (6) of the through-passage (4) has a fluoropolymer coating (7) which, under normal operating conditions, provides a seat between the body (3) and the shutter (5) when the latter is in position. in his second position. This fluoropolymer coating (7) is usually perfluoroalkoxy or polytetrafluoroethylene. Perfluoroalkoxy is, however, preferred over polytetrafluoroethylene because it can be melted and used with conventional injection and molding techniques.

The shutter (5) is for example actuated in displacement by an opening / closing device (8) for moving it from one position to another.

The shutter (5) can be covered with a layer of enamel (9), although this is not systematic.

At the opening (6) of the through passage (4), the valve (1) of the invention comprises a sealing ring (10) made of a non-metallic material resistant to high temperatures.

Under normal operating conditions, this sealing ring (10) is completely covered by the coating (7).

fluoropolymer.

Since it is completely covered by a fluoropolymer coating (7) under normal operating conditions, the sealing ring (10) is at a distance from the shutter (5) when the latter is in its second position. position, this distance corresponding to the thickness of the coating (7) fluoropolymer.

Being completely covered by a coating (7) fluoropolymer, the sealing ring (10) does not interact with the product contained in the reactor (2) and likely to flow through the valve (1). When it is in graphite material known for its reducing power, the sealing ring (10) does not interact chemically with the product contained in the reactor (2) and is not likely to react violently with powerful oxidants.

If it were not completely covered by a fluoropolymer coating (7), the sealing ring (10) would be able to react chemically with the product contained in the reactor (2) and thus to denature it. In the case where the reactor (2) contains a strong oxidant, the sealing ring (10) would react violently with it, which would alter the chemical reaction taking place in the reactor and could also damage the valve (1). ).

In addition, the sealing ring (10) has a smaller internal diameter than the opening (6) of the through passage (4) when it is considered unlined (7) fluoropolymer.

Thus, under normal operating conditions, the sealing ring (10) does not interact with the shutter (5) and the valve (1) operates in a conventional manner, as if it did not include a sealing ring (10).

In case of failure of the fluoropolymer coating (7), for example when the latter melts due to high heat or when it burns in case of fire, the sealing ring (10) is exposed. and can interact with the shutter (5).

Thus, when the shutter (5) is in its second position, the sealing ring (10) provides a seat between the body (3) and the shutter (5) and comes into contact with the shutter (5). ) so as to interrupt the flow of the product through the through passage (4).

The support of the shutter (5) on the sealing ring (10) thus seals the valve (1) in case of failure of the coating (7) fluoropolymer. In the case where the shutter (5) presses on the top of

the sealing ring (10), this sealing is further enhanced by the pressure exerted on the shutter (5) by the product contained in the reactor (2).

The material of the sealing ring (10) is chosen so that the contact between the shutter (5) and the sealing ring (10) is satisfactory, even when the enamel layer (9) covering the shutter (5) is faulty.

In order to resist creep and provide a satisfactory seal when in contact with stainless steel or enamel, the sealing ring (10) is designed to withstand temperatures above 750 ° C and is preferably in graphite.

The sealing ring (10) is designed to withstand the pressure exerted by the shutter (5) and not to break. Thus, it preferably has a thickness D between 1 and 10 millimeters, preferably between 2 and 8 millimeters and more preferably between 3 and 5 millimeters.

The sealing ring (10) is preferably housed in a groove (11) provided in the periphery of the opening (6) of the through passage (4) of the valve (1). According to a preferred embodiment of the invention, the depth P of said groove (11) is provided so that the thickness F of the fluoropolymer coating (7) situated above the sealing ring (10) is greater than the thickness E of the fluoropolymer coating (7) located elsewhere on the body (3) of the valve (1).

It is obvious that the present description is not limited to the examples explicitly described, but also includes other embodiments and / or implementation. Thus, a described technical characteristic may be replaced by an equivalent technical characteristic without departing from the scope of the present invention and a described step of implementing the method may be replaced by an equivalent step without departing from the scope of the invention as defined. by the claims.

Thus, although the invention has been described in the context of bottom tank valves for a reactor, a mixer or storage equipment in which the seat on which rest an enamelled shutter is covered with a fluoropolymer layer, it is obvious that the invention can be applied to any other device for which have sought enhanced security to ensure a certain tightness in case of fire or high heat having the effect of destroying or reducing a layer fulfilling this role sealing under normal conditions.

CLAIMS

1. Valve (1) comprising a body (3) provided with a through passage (4), and comprising a shutter (5) movable between a first position in which it allows the flow of a product through the passage and a second position in which it interrupts the flow of the product, wherein the opening (6) of the through passage (4) comprises a fluoropolymer coating (7) which, under normal operating conditions, provides a seat between the body (3) and the shutter (5) when the latter is in its second position, characterized in that it comprises at the level of the opening (6) of the through passage (4) a sealing ring (10) made of a non-metallic material resistant to high temperatures which, under normal operating conditions,is completely covered by the fluoropolymer coating (7) and, in case of failure of the fluoropolymer coating (7), provides a seat between the body (3) and the shutter (5) and comes into contact with the shutter (5) when the shutter (5) is in its second position so as to interrupt the flow of the product through the through passage (4).

2. Valve (1) according to claim 1, characterized in that the sealing ring (10) withstands temperatures above 750 ° C.

3. Valve (1) according to claim 1 or 2, characterized in that the sealing ring (10) is graphite.

4. Valve (1) according to any one of the preceding claims, characterized in that the sealing ring (10) has a thickness D between 1 and 10 millimeters, preferably between 2 and 8 millimeters and more preferably included between 3 and 5 millimeters.

5. Valve (1) according to any one of the preceding claims, characterized in that the sealing ring (10) has an internal diameter less than the opening (6) of the through passage (4) when the it is considered unlined (7) fluoropolymer.

6. Valve (1) according to any one of the preceding claims, characterized in that the coating (7) fluoropolymer is perfluoroalkoxy or polytetrafluoroethylene.

7. Valve (1) according to any one of the preceding claims, characterized in that the shutter (5) comprises an outer layer of enamel (9).

8. Valve (1) according to any one of the preceding claims, characterized in that the sealing ring (10) is housed in a groove (11) provided in the periphery of the opening (6) of the through passage (4) of the valve (1).

9. Valve (1) according to the preceding claim, characterized in that the depth P of the groove (11) is provided so that the thickness F of the coating (7) fluoropolymer located above the ring of sealing (10) is greater than the thickness E of the fluoropolymer coating (7) located elsewhere on the body (3) of the valve (1).

10. Valve (1) according to any one of the preceding claims, characterized in that the shutter (5) is axially movable relative to the through passage (4) so ​​as to move away from and towards the opening (6) of the through passage (4).