EP0893347A1 - Cryogenic valve in an apparatus for packaging a product - Google Patents

Abstract

A cryogenic liquid is delivered to its point of use via an insulated pipe (16) with a flow control valve. The control valve has a conical seat between its inlet and outlet pipes, which can be closed by valve obturator moving downwards. The downstream part of the valve body has a vent pipe (34) which is connected to the main supply pipe to allow gas to escape.

Description

The present invention relates to an apparatus supply of a cryogenic liquid, of the type including a thermally insulated main line in which is mounted a throttling member of the liquid flow.

It applies in particular to regulated supply liquid nitrogen to moving containers for their inerting and / or their pressurization.

As is well known, the heat inputs unavoidable in pipes carrying liquids cryogenic cause bubbles to appear in these liquids, making it difficult to transfer throughput constant, especially for flow rates below 10 l / h.

A situation particularly sensitive to this phenomenon occurs in the pressurization process of cans with liquid nitrogen. In this technical, a row of cans in contact each other scrolls, after filling them with a non-gaseous product, for example by a flat drink, under a nozzle from which flows a thin stream of liquid nitrogen. Each box thus receives a few drops of nitrogen liquid, then is closed tightly.

The start of nitrogen vaporization, before closing the box, expels air from the box, ensuring thus inerting the product. Then, after closing the box, the end of the nitrogen vaporization puts the overpressure box, which allows it to be handled at will without risk of denting or crushing.

As we understand, if the amount of nitrogen liquid received by a box is too low, the pressurization will not be sufficient to maintain the integrity of the box and, if this quantity is excessive, the box may explode.

Current filling lines scroll several dozen boxes per second on a single line, and higher and higher rates are considered. If we also take into account the periods acceleration and braking of chains during start-up and shutdown phases of the installation, understands that a very precise adjustment of the nitrogen flow liquid spilled at all times is critical for the process development.

The invention aims to allow adjustment improved flow of cryogenic liquid. To this end, it relates to a device of the aforementioned type, characterized in that it includes a degassing pipe tapped on the main pipe downstream of the organ strangulation.

• la conduite de dégazage est piquée sur la partie supérieure de la conduite principale;
• l'organe d'étranglement est l'obturateur d'une vanne qui comprend un corps de vanne définissant un tronçon intermédiaire amont et un tronçon intermédiaire aval de la conduite principale, ainsi qu'un siège situé entre ces deux tronçons, l'obturateur étant monté mobile dans le corps par rapport au siège, et le corps de vanne est muni d'un perçage qui débouche dans la partie supérieure du tronçon intermédiaire aval et qui est relié à la conduite de dégazage;
• la conduite de dégazage s'étend dans l'enveloppe extérieure de la conduite principale;
• l'appareil comprend en outre un réservoir de liquide cryogénique du fond duquel part la conduite principale, et la conduite de dégazage débouche dans la partie supérieure de ce réservoir.

The apparatus according to the invention may include one or more of the following characteristics:

• the degassing pipe is tapped on the upper part of the main pipe;
• the throttling member is the shutter of a valve which comprises a valve body defining an upstream intermediate section and an intermediate downstream section of the main pipe, as well as a seat situated between these two sections, the shutter being mounted movable in the body relative to the seat, and the valve body is provided with a bore which opens into the upper part of the downstream intermediate section and which is connected to the degassing pipe;
• the degassing pipe extends into the outer casing of the main pipe;
• the apparatus further comprises a cryogenic liquid tank from the bottom of which leaves the main pipe, and the degassing pipe opens into the upper part of this tank.

The invention also relates to a valve cryogenic for such an apparatus. This valve cryogenic, of the type comprising a valve body which defines an upstream pipe section, a section of downstream pipe, as well as a seat located between these two sections, and a shutter mounted movable in the body by relative to the seat, is characterized in that the body of valve has a hole that opens into the part upper section of the downstream section.

In one embodiment of this valve, the seat is frustoconical and converge downwards and is extended downwards by a cavity, and the shutter includes a frustoconical conjugate part of the seat and a lower part adapted to be received with play in said cavity when the shutter is in position closing.

The invention also relates to an installation for packaging a product in containers scroll, comprising a nitrogen supply apparatus liquid as defined above, arranged above the container conveyor, between a filling station containers with the product and a closing station containers.

• la Figure 1 représente schématiquement, partiellement en coupe, une installation de conditionnement conforme à l'invention;
• la Figure 2 représente en coupe, à plus grande échelle, la vanne de régulation de l'installation de la Figure 1; et
• la Figure 3 représente schématiquement, à encore plus grande échelle, un détail de cette vanne.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which:

• Figure 1 shows schematically, partially in section, a packaging installation according to the invention;
• Figure 2 shows in section, on a larger scale, the regulating valve of the installation of Figure 1; and
• Figure 3 shows schematically, on an even larger scale, a detail of this valve.

Schematically shown in Figure 1 a liquid product packaging installation non-carbonated in a row of cans cylindrical contiguous 1. These boxes are carried by a conveyor 2 and pass successively, in the direction of arrow F, under a station 3 for filling boxes with the product, under a device 4 for supplying a net 5 of liquid nitrogen, and under a crimping station 6 a waterproof cover 7.

Posts 3 and 6 are conventional, so that only the apparatus will be described below 4.

The apparatus 4 comprises, from upstream to downstream, a double-shell liquid nitrogen tank 8, the upper openings of the two envelopes being connected by a thermally insulating collar 9. The envelope exterior 10 is equipped with a fixing structure 11 to an appropriate support (not shown). Col 9 is crossed by a supply line 12 controlled by a 12A liquid nitrogen level sensor in the enclosure inside 13 of the tank, and by a degassing 14 leading to the surrounding atmosphere. The tank is additionally equipped with various accessories conventional, not shown.

The bottom of the envelope 10 has an orifice from which the outer casing 15 of a pipe starts main 16 for supplying liquid nitrogen. This pipe consists of a first section 17 extending vertically downward, from a second horizontal section 18, and a third section 19 extending vertically downwards.

Similarly, from the bottom of the inner envelope 13 of the tank leaves the inner tube 20 of the pipe 16, which extends coaxially along the envelope 15. At the downstream end of the pipe, a device shutter 21 is provided between the casing 15 and the tube 20. The inter-wall space of the pipe 16, as well as that of the reservoir 8, which communicates with the previous one, are thermally insulated under vacuum in a conventional manner.

Optionally, as shown in dashed lines in Figure 1, a liquid nitrogen distribution head 22, interchangeable, is provided at the downstream end of the driving 16.

In the horizontal section 18 is mounted a valve 23. The latter (Figures 1 and 2) includes essentially a valve body 24 surrounded by a thermal insulation 25, a shutter 26 actuated by a vertical control rod 27, and an actuator 28 located at the upper end of the rod 27.

As best seen in Figure 2, the body of valve 24 has, from its upper face, a vertical bore 29 extended downwards by a counter bore blind with the same axis X-X, which defines a cavity cylindrical 30. A section of upstream pipe 31, inclined downwards, from a side face of the valve body and opens into the cavity 30. Its diameter is slightly lower than that of the counterbore (Figure 3). A downstream pipe section 32, inclined downwards in the same way as section 31, starts from the bore 29 and opens onto the opposite side face of the body valve. When the valve is in the open position, the pipe sections 31 and 32 and the space between them links can be considered part of the main line 16, the sections 31 and 32 forming respectively upstream and downstream intermediate sections of this conduct.

Furthermore, a hole 33 made in the downstream part of the body 24 opens at a point intermediate of the downstream section 32 and is connected to joint sealed, by welding, to a degassing tube 34. This last (Figure 1) extends upstream between the tube 20 and the casing 15 of the pipe 16, then in space inter-wall of the tank 8, and ends with a butt 35 which crosses with watertight seal the part inner envelope 13 and opens into this one.

The two parts are shown in Figure 2 of the horizontal section of the tube 20, which are connected by welds at the outlets of the pipe sections 31 and 32.

The bore 29 and the counter bore 30 are connected by a frustoconical seat 36. The shutter 26 has a intermediate part 37 frustoconical conjugate of the seat 36, fitted with a Teflon seal 38, a lower part 39, also of general shape frustoconical but with a much larger opening angle weak, and an upper link 40. This last is connected to the lower end of the rod 27 by a ring 41 which allows a slight clearance angle of the shutter around the X-X axis.

At rest, part 37 of the shutter 26 is applied to the seat 36, and its lower part 39 is received with a large clearance in the cavity 30 (low position in Figure 3).

In operation, the shutter is lifted from its seat (high position in dashed lines in Figure 3), which connects the pipe sections 31 and 32.

The passage of liquid nitrogen through the region valve body center causes a pressure drop, which produces a partial vaporization of the liquid (flash). Thanks to the presence of the hole 33 connected to the tube 34 and, from there, via the reservoir 8 and the tube 4, to the atmosphere, the flash gas thus produced is evacuated liquid nitrogen immediately and does not practically not at the downstream part of the pipe 16.

We understand by reading the above all the interest that there is in this situation of use a throttling device (flow adjustment according to the more or less obturating position of the organ and therefore variation of the pressure drop introduced), at stitch out the degassing line on the upper part of the main pipe, so to evacuate by this means very effectively and selective the formed gas phase which accumulates naturally at the top of the pipe main, while the cryogenic liquid (thereby substantially frank) naturally circulates in the lower part of the main pipe.

The effectiveness of the invention has been demonstrated by the following tests: with the apparatus 4 described above, the shutter is lifted 14% of its maximum travel leads to almost instantaneous warm-up and flow of liquid nitrogen, at exit, having a regularity sufficient for the application in question.

However, with the same device without the drilling 33 and degassing line 34, a lifting of the 46% shutter is required to obtain flow liquid nitrogen required, but the flow is irregular; of more, several minutes are necessary to obtain the diet.

Claims (7)

Liquid supply apparatus cryogenic, of the type comprising a main pipe (16) thermally insulated in which is mounted a liquid flow throttling member (26), characterized in that it includes a degassing pipe (34) tapped on the upper part of the pipe main (16, 31, 32) downstream of the organ throttle (26). Apparatus according to claim 1 in which the throttle member (26) is the shutter a valve (23) which comprises a valve body (24) defining an upstream intermediate section (31) and a intermediate downstream section (32) of the pipe main, as well as a seat (36) located between these two sections, the shutter (26) being movably mounted in the body relative to the seat, characterized in that the valve body (24) is provided with a bore (33) which leads into the upper part of the section downstream intermediate (32) and which is connected to the degassing (34). Apparatus according to any of claims 1 or 2, characterized in that the pipe degassing (34) extends in the outer casing (15) of the main line. Apparatus according to any of Claims 1 to 3, characterized in that it comprises in addition to a bottom cryogenic liquid reservoir (8) from which the main pipe (16, 31, 32) starts, and in this that the degassing pipe (34) opens into the part top of this tank. Cryogenic valve, of the type comprising a body valve (24) which defines an upstream pipe section (31), a downstream pipe section (32), as well as a seat (36) located between these two sections, and a shutter (26) mounted movable in the body relative to the seat, characterized in that the valve body (24) is provided a hole (33) which opens into the upper part of the downstream section (32). Cryogenic valve according to claim 5, characterized in that the seat (36) is frustoconical and converges downwards and is extended downwards by a cavity (30), and in that the shutter (26) comprises a frustoconical part (37) conjugate of the seat and a part lower (39) adapted to be received with play in said cavity when the shutter is in the position of closing. Product packaging installation in moving containers (1), characterized in that it includes a nitrogen supply device liquid according to any one of claims 1 to 4, placed above the container conveyor (2), between a station (3) for filling the containers with the product and a container closure station (6).

Images