Aseptic constant flow valve

DESCRIPTION

The present invention relates to an aseptic constant flow valve comprising a valve housing with an inlet and an outlet and a valve body, which is movable by means of a drive mechanism located in a drive chamber having a entry and exit, said actuation mechanism including a pressure sensitive element that forms a wall in the actuation chamber and which is mechanically connected to the valve body.

In the packaging of liquid goods, for example, milk, cream, juices or the like, in non-returnable packaging containers, automatic packaging machines are used which are connected to units for the treatment and transport of the pipeline through a pipeline. content to the machines. To ensure that the content flows to the packaging machine with a uniform and predetermined volume per unit of time, a so-called constant flow valve is usually present upstream of each packaging machine and takes care that regardless of variations in pressure in the feeding duct, the flow remains constant. The hygienic demands on said valve are very high, especially when the packaging machine is of the aseptic type, that is, when it manufactures containers that have to be filled with contents previously subjected to sterilization treatment.

In other words, the use of flow valves consisting of product ducts implies that the valve must be of a design such that it can be cleaned and washed easily. When the valve is intended for sterile contents, it is also important that it be in a way that allows it to be sterilized after washing. Said sterilization can be done, for example, with the help of water vapor or some chemical sterilizing agent, for example, hydrogen peroxide.

Constant flow valves previously known (DE-A-2 256 413) are of a design that makes them barely suitable for use in conjunction with aseptic packaging machines. The valves comprise a valve housing with a removable valve body, the position of which is controlled with the help of a drive mechanism based on the actual pressure in the conduit to which the valve is connected. The actuation mechanism and its components are generally of unprotected design, so they will come into contact with the contents, making it difficult to clean the valve and resulting in it being totally unsuitable for use together with sterile contents.

An object of the present invention is to provide a constant flow valve that is suitable for use in conjunction with sterile contents, and which is not subject to the disadvantages that characterize the constant flow valves used so far.

Another object of the present invention is to provide an aseptic constant flow valve, which is of simple and reliable design, and which can therefore be expected to provide high operational safety during prolonged use.

Another object of the present invention is to provide a constant flow valve, which stands out suitable for sterilization circulation with the aid of sterilizing agents, for example, steam or hydrogen peroxide, used in a customary manner.

These and other objects have been achieved, in accordance with the invention, in a constant flow aseptic valve comprising a valve housing with an inlet and outlet and a valve body, which is movable by means of a drive mechanism located in a drive chamber that has an input and an output, said actuation mechanism including a pressure sensitive element that forms a wall in the actuation chamber and which is mechanically connected to the valve body, whose valve has been given the characteristic that the liquid flow controlled by said valve is driven through the drive chamber, but separated from the drive mechanism of the valve body.

Preferred embodiments of the valve, in accordance with the invention, have also received the characteristics that are deduced from the accompanying subsidiary claims.

By means of the constant flow valve arrangement according to the invention, with a drive chamber through which the passage contents flow, and with a drive mechanism whose components form an integral part and are separated from the content, a valve is obtained constant flow that is very suitable for aseptic use, and that it can be of washing by circulation and sterilized by means of the type of washing and sterilizing agent used in a customary way in the food industry. The positioning of the actuating chamber upstream of the valve housing, looking in the direction of the flow of the content, also ensures that the valve works well with a rapid and exact correction of the flow in the case of pressure variations.

Next, a preferred embodiment of an aseptic constant flow valve will be described in more detail, according to the invention, with specific reference to the attached schematic drawing, which shows only the details necessary for the understanding of the invention.

The figure shows, partially in section, an aseptic valve of constant flow according to the invention, which can be installed in the feeding set for liquid contents, for example, milk, towards a packaging machine. The purpose of the constant flow valve is to ensure that the contents are sent to the packaging machine with a constant flow that can be precisely adjusted to a specific value, which cannot subsequently be affected by variations in pressure and sharp increases in the same, in the product duct.

The constant flow valve illustrated consists of two main parts, which are a valve housing 1 on the right in the figure, and

013 589 a drive chamber 2 on the left in the figure. The valve housing 1 and the actuation chamber 2 are physically connected to each other by means of a spacer member 3. The actuator chamber 2 has an inlet 4, which is connected to a supply conduit for contents, not shown, and a outlet 5 which, through a connection tube 7 provided with a control valve 6, is connected to an inlet 8 to the valve housing 1. Finally, from the valve housing 1, an outlet 9 leads away, and is connected to a feed tube (not shown) towards a packing machine of known type.

The outlet 9 is T-shaped, and has on its part located in the valve housing 1, with two valve seats 10, which together with a two-part valve body 11, forms a conventional-type balanced seat valve .

Within the aforementioned tubular spacer member 3 there is a valve 12, coaxially arranged, which extends into the extension of the valve body and is attached thereto. The rod 12 is surrounded by a helical spring 13 of compression, one end of which rests against a plate 14 provided with holes, located in the spacer element 3, and whose opposite end rests against a first pressure-sensitive element 15, which forms a wall in the drive chamber 2. On the side of the plate 14 facing the valve housing 1, there is a second pressure-sensitive element 16, which is identical to the first pressure-sensitive element 15, but mounted in symmetrical arrangement. Each of the two pressure-sensitive elements 15, 16 comprises a piston 17, which by means of an annular rolling membrane 18 is hermetically bonded to liquids at the two ends of the spacer member 3, respectively. Between the two pressure-sensitive elements 15, 16, there is thus a chamber separated from the contents, in which the rod 12, the spring 13 and the plate 14 are located. To reveal a possible leak of liquid through the elements 15 , 16 sensitive alapresion, the spacer member 3 is provided with control openings in a conventional manner.

As can be seen in the figure, the constant flow valve is composed of several parts, which are manufactured from stainless steel and are screwed between them with the help of the so-called dairy joints. In addition to making simple assembly and disassembly possible, it also ensures a simple replacement of the parts, when justified. The materials chosen allow washing, even with strong cleaning agents, for example, caustic soda, and sterilization with the help of steam or hydrogen peroxide. Finally, the design has been carried out in such a way that the washing and sterilizing agent can flow without obstruction through the constant flow valve, without the circulation being constricted by blind passages or corners.

During operation of the constant flow valve according to the invention, the previously sterilized content, for example, the so-called UHT milk, flows through the feed line (not shown) to the inlet 4 of the chamber chamber 2. With this, the content comes into contact with the first pressure-sensitive element 15, and then flows through the outlet 5 of the actuating chamber 2 and the connection 7, towards the control valve 6. This is manually or automatically adjusted to the desired value, so that a predetermined flow per unit of time is obtained to the packaging machine. As a result, a pressure drop occurs in the contents when it flows over the valve housing 1 through the inlet 8. In the valve housing 1, the content comes into contact with the second pressure-sensitive device 16, and then the flow exceeds the valve body 11 and through the T-shaped outlet tube 9 leaves the valve housing towards the subsequent packaging machine, not shown in the drawing.

Depending on the setting of the control valve 16, a greater or lesser pressure difference will occur between the content in the actuating chamber 2 and that contained in the valve housing 1. The two elements 15, 16 sensitive to the pressure will be activated in the procedure, so that together with the stem and the valve body 11, they will strive to move in the direction of the lower pressure, that is, to the right in the figure. However, with the help of the spring characteristics chosen from the compression spring 13, said effort is counteracted so that the valve body 11 is maintained at such distance between the two valve seats 10, that the flow through the tube T-shaped outlet 9 corresponds to the flow through the control valve 6, as a result of which a uniformly stable state is established. Now, if there is any variation in the pressure, for example an increase in it, in the content feed tube, the pressure in the drive chamber 2 will increase. Due to the unchanged position of the control valve 6, the two pressure-sensitive elements 15, 16 will be immediately subjected to a greater pressure difference than the previous one, which means that they will displace the stem by overcoming the effect of spring 13 on they are directed to the right, so that the valve body 11 approaches the valve seats 10 and the free airway is reduced through free through the outlet 9, thus making the flow to the packaging machine remain unchanged, despite the increase in pressure in the feed duct. In the case of sudden reductions in the pressure in the supply line, the constant flow valve regulates correspondingly in the opposite direction, so that the free area through alidade 9 increases, in order to compensate for the decrease in pressure in the duct and take care that the flow to the packaging machine remains constant all the time.

The regulating characteristics of the constant flow valve depend on many factors, for example, the sizes of the valve and the tube, the area of ​​the pressure sensitive elements 15, 16, and the spring design 13. Therefore, in

013 589 each particular case should be carried out the corresponding calculations to adapt the valve according to the pressure and flow of the product calculated. In the application of the constant flow valve according to the invention, cited above, that is, between the feed line for the content and a known type packing machine, the valve must be designed for a capacity of between 1 and 10 cubic meters of content per hour, and a typical pressure of approximately 1 bar, which, however, can vary between 0.5 and 5 bars. However, it is technically possible to design the valve so that significantly higher flows and pressures can be treated with it.

Since the valve housing 1, as well as the actuating chamber 2 and the intermediate member, are placed in series along the flow path, the constant flow valve allows effective washing circulation, whereby each part of the The valve that is normally in contact with the contents can be cleaned effectively. The parts that are in contact with the contents, are relatively uncomplicated, and do not have corners or gaps that can make cleaning difficult. The rod 12, the spring 13 and the plate 14, as well as the parts carrying the pressure-sensitive elements 15, 16, are separated from the contents by means of the two rolling membranes 18. The location of said parts in the actuating chamber 2, which through the control holes is in contact with the surrounding atmosphere, also means that any leakage in the pressure sensitive elements is immediately revealed. The design provides good regulation accuracy, and is perfectly capable of compensating for variations in pressure. This is partly due to the fact that the actuating chamber is located upstream of the valve housing 1, seen in the direction of the flow, as a result of which the valve reacts quickly and with great precision, even in the case of relatively contained contents. viscous

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