RU2575511C2 - Vacuum pump of vacuum-driven packing machine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to vacuum pump to be used in the vacuum-driven packing machines. Vacuum pump comprises the cylinder (11) composed by the jacket of two parallel cylindrical chambers intersected in crosswise direction, their axes located in one plane and one of their sides making the wall provided with a suction hole (17), and by outer jacket enveloping that of said two parallel cylindrical chambers to make a closed chamber with inlet and outlet. Said chamber allows the circulation of fluid that effects the heat exchange. Claimed machine comprises the driven crankcase (12) accommodating the engine, pump rotors driving and timing components, said rotors being arranged in cantilever to make the support the cylinders (11) and to centre them.

EFFECT: enhanced performances, perfected design, ease of dismantling, cleaning and reassembly.

12 cl, 3 dwg

Description

Application area

The present invention relates to the technical field of vacuum packaging machines (e.g., "chamber machine", "thermoformer" or "tray sealer"). In particular, the present invention relates to vacuum pumps used in these machines.

State of the art

Currently, vacuum packaging machines are used in a wide variety of industrial fields. Oxygen contained in the air adversely affects the quality and duration of storage of products. Therefore, it is desirable to carry out certain industrial processes, for example, packaging products under partial or complete vacuum. Thus, vacuum packaging of products significantly reduces the possibility of spoilage by air.

In particular, the areas in which vacuum packaging is most commonly used are the food industry, the cosmetics industry and the pharmaceutical industry, as these industries must at all times ensure that their products reach consumers in perfect condition.

Therefore, vacuum packaging machines must necessarily contain a source of vacuum. This vacuum source (which is usually a vacuum pump) removes the air contained in the package before closing it. In an application, a modified atmosphere is injected into it before closing the package. This method is often used in the food industry (in particular, for packaging fresh meat), since it allows you to simultaneously maintain the original form of food products, as well as, even after very long storage, their freshness, which consumers require.

Currently, several types of machines are usually used, allowing vacuum packaging. These various types of machines differ, in particular, in the type of packaging they receive, in their design or in the field of application.

Currently, vacuum packaging machines, known as the “tray sealer” or “sealing machine”, are widely used, in particular in the food industry.

The sealer is usually part of a line for packaging food in plastic trays or in other appropriate containers. In such an installation, a series of trays are gradually moved on a conveyor belt or using another similar device to a filling station, on which a predetermined dose of the product is placed in each tray. After that, the tape with trays continues to move to the sealing machine, in which the trays are hermetically sealed with a protective film, and then stored for further transportation and sale.

Depending on the applications, vacuum can be created in the trays before being sealed and / or they can be filled with a gas mixture (known as “modified atmosphere” or MAP).

Another type of vacuum packaging machine is “thermoformer”. Since thermoformers are often used to pack medicines (tablets, pills, lozenges, etc.) in the form of blisters, they are also called “blister packaging machines”.

Thermoformer is a machine that allows you to get packaging due to deformation of the plastic plate. For this, an electrical resistance is usually provided for heating the plastic plate in order to soften it. After that, use the mold to give the plate the desired shape before it is cooled and removed from the machine.

Finally, machines called “chamber machines” or “chamber machines” operate using plastic bags. They are widespread in the food industry, but are also used for packaging other consumer goods, surgical instruments, or similar applications. At the first stage, the bags are filled with the product intended for packaging. Then the bags are placed in the working chamber, closed by a cap, after which a vacuum is created in the bag by removing air from the working chamber. In some bag applications, a controlled atmosphere is created. Ultimately, the bag is closed by thermal welding.

There are also other types of vacuum packaging machines that differ from these three types, in particular the type of packaging used.

As for the various vacuum sources for these machines, central vacuum systems have long been known, in particular for vacuum packaging machine lines. Such central vacuum installations require a piping network through which air circulates between the package and the central source. Quite often, these central vacuum units contain many vacuum chambers and reservoirs that are associated with different pressure levels, with each stage having a different pressure level.

These central vacuum units usually have large capacities, and, in particular, their advantage is the ability to "power" simultaneously many machines. At the same time, the pipeline network, tanks and chambers are expensive, take up a lot of space to maintain the necessary pumping power, and moreover, their cleaning is very time-consuming.

Also known are pumping units containing one or more fore-vacuum pumps and boosters. Typically, fore-vacuum pumps are located outside the vacuum packaging machine, in particular for reasons of space saving, after which they are connected to it by a pipeline. In such an assembly, shut-off valves and other auxiliary elements are also provided to create the necessary vacuum. As a rule, control of all pumps in such a pump unit is provided by an automatic machine.

This type of pumping unit also has dimensions and cleaning problems, moreover, it is necessary to provide optimal control of various system elements in them, which can create problems at the level of synchronization and / or adjustment.

Solutions are also known in which a vacuum pump is integrated in the casing of a vacuum packaging machine and is directly connected to the part of the machine in which it is necessary to create a vacuum. Although this option is preferred from the point of view of connecting the pump, its disadvantage is that it is limited only to pumps having strictly defined dimensions. In other words, the choice of pumps is extremely limited, and sometimes it is difficult and even impossible to find a pump with the necessary characteristics that matches the shape and design of the packaging machine.

On the other hand, insulated pumps and fore-vacuum pumps in these pump units are in most cases vacuum pumps with a lubricated impeller. The principle of operation of pumps of this type raises the problem of oil change, which is inextricably linked with the nature of the pumping process. This requires appropriate personnel, time to stop the packaging lines, as well as oil consumption and its processing. Due to this, operating costs increase significantly.

In addition, there is also a high risk of contamination of the packaged products at the inlet with oil coming from a vane vacuum pump. This creates a problem in cases where the packaged products are food or pharmaceutical products, for which it is necessary to strictly observe the established standards of hygiene. Considering the performance of an automated vacuum packaging machine, the damage can be huge. Consequently, there is a need for special and careful monitoring.

Recent solutions are known in the food industry that use not vacuum pumps with a lubricated impeller, but dry auger pumps. These pumps are based on standard industrial pumps already marketed by manufacturers, but minor changes have been made to them related to food industry regulations.

Food industry standards require, in particular, adherence to elevated levels of hygiene, which requires regular cleaning and disinfection of pumps. However, access to the working rotors of these pumps is often difficult and requires complete removal of the pump, which makes cleaning difficult. Likewise, mounting various parts of the pump after cleaning is also difficult due to alignment problems and precise adjustment of the rotors, which requires the intervention of qualified personnel.

In addition, industrialists are constantly striving to reduce the dimensions of components in production plants, in particular in vacuum packaging machines, in which the space under the conveyor plane of packaged products is extremely limited. At the same time, they are constantly striving to increase the efficiency of pumping devices in terms of productivity and energy intensity.

Disclosure of invention

The present invention is intended to eliminate all of the aforementioned disadvantages and to provide a vacuum pump adapted for use in vacuum packaging machines. In particular, the invention is intended to offer a new vacuum pump in which the reduction in volume is combined with improved characteristics and the design of which makes it easy to dismantle, clean and re-install without involving highly qualified personnel.

In connection with this object of the invention is a vacuum pump according to paragraph 1 of the claims.

In particular, the technical result of the invention is achieved using a vacuum pump intended for use in vacuum packaging machines and containing:

- cylinder formed

the casing of two parallel cylindrical chambers intersected in the transverse direction, the axes of which lie in the same plane and one of the sides of which is the wall in which the suction hole is located, and

an outer casing covering the casing of two parallel cylindrical chambers, forming an enclosed space having an inlet and an outlet that circulates a fluid that carries out heat exchange,

- two pump rotors located in parallel cylindrical chambers and rotated by the engine, and

- a drive crankcase, which contains the engine, drive and synchronization components of the pump rotors, in which the rotors are mounted cantilever and which serves to support and center the cylinder.

In a particular embodiment, the back of the crankcase is a closed housing including a stator of an electric motor. In particular, this housing may contain electric motor control electronics, means for visually monitoring the operating parameters of the pump and cooling means. The advantage of this design is that the components associated with the motor can be separated from the active part of the pump, which provides easier control as well as easier handling and maintenance.

In an embodiment of the present invention, the motor is cantilevered, and the rotor of the motor is directly connected to the shaft of one of the pump rotors. An advantage of this embodiment is, in particular, a reduction in the overall size of the pump. In this case, direct contact between the rotor of the motor and the shaft of the pump rotor provides a more efficient casting.

However, in another embodiment of the present invention, the motor in the pump has its own thrust bearings, and the motor rotor is connected to one of the pump rotors by means of a coupling connection. An advantage of this embodiment is the ability to use a “classic” engine. In addition, installing this engine in its own thrust bearings makes it easier to integrate it into the pump. In addition, replacing the engine (for example, in the event of a breakdown) can be made easier than in the case of an engine directly connected to the shaft of the pump rotor.

In another embodiment of the inventive pump, it comprises a support providing connection to the floor, connecting the cylinder so that the flow of evacuated gases and flushing fluids follow the natural path to the discharge opening, producing the effect of a silencer. It should be noted that the support can be an integral part of the outer casing of the cylinder, while maintaining all its functions. This simplifies fabrication by machining and reduces the number of pump components.

Preferably, the plane in which the axes of the cylindrical chambers of the pump are located is horizontal. The advantage of this arrangement is the compact configuration, which can significantly reduce the size and use of space. Cleaning and / or maintenance of the pump can be made much easier, given that access to the rotors is facilitated and that wastewater and / or flushing agents can leak without coming into contact with other elements of the pump.

In a particular embodiment of the present invention, the suction port is located on the side of the cylinder opposite to the drive crankcase, or on the side of the cylinder parallel to the upper side of the support. This location of the suction opening further reduces the dimensions of the pump. Considering that the suction port is located on one of the most accessible sides, the connection to the gas line of the machine is facilitated. It also follows that this design provides a direct connection (that is, only with pipes providing a natural flow of gas to be removed). A direct consequence of this is an increase in pump performance.

In a pump according to another embodiment of the present invention, the pump rotors have first and second rotor rotational direction organs in which the rotors are cantilevered. As will be explained in more detail below, this design makes it easier to dismantle and replace the cylinder and does not affect the normal operation and adjustment of the rotors.

Preferably, the pump rotors are screw type rotors, respectively, with left turns and right turns that rotate in the cylinder, going into each other, in opposite directions. The advantage of dry pumps of this type is the lack of oil, which simplifies their use in areas with increased hygiene requirements. Thus, the possibility of contamination can be completely eliminated. In addition, these pumps are compact and feature high performance. Finally, due to the simple control of the rotation speed, it is possible to adjust the flow rate and / or vacuum level.

In a preferred embodiment of the present invention, the first rotation direction organs are located at the ends of two elongated arms that are fixedly connected to the drive housing, while the second rotation direction organs are directly integrated in the drive housing. In this way, console installation is easier. When the cylinder is removed to provide access to the rotors (for example, for cleaning), the cantilever mount using the direction of rotation allows you to not make changes to the adjustment of the rotors. Thus, the dismantling and installation in place of the elements of the claimed pump can be performed by personnel without special qualifications.

Finally, the rotation direction organs may be ball bearings. Ball bearings are mechanical elements that have many advantages in this application. In addition, they are relatively cheap.

The invention will be more apparent from the following description, presented by way of non-limiting example, with reference to the accompanying drawings, in which:

1 is an isometric view of a vacuum pump according to an embodiment of the present invention.

FIG. 2 is a sectional view of the vacuum pump shown in FIG. 1 along a plane that passes through the longitudinal axis of the rotors.

Figure 3 is an isometric view of the vacuum pump shown in figure 1, with a cylinder separated from the drive housing and from the base.

DETAILED DESCRIPTION OF THE INVENTION

1 schematically shows a vacuum pump 10 according to a preferred embodiment of the present invention. As already mentioned above, this vacuum pump 10 is intended, in particular, for use in vacuum packaging machines. However, it should be noted that the range of use of the vacuum pump 10 is not limited only to this application. One skilled in the art can readily understand that this vacuum pump 10 can be successfully used for other purposes.

To meet current market requirements and eliminate the above-mentioned disadvantages, this vacuum pump 10 has a special configuration.

In particular, the housing of the pump 10 comprises a cylinder 11, which covers the "active" part of the vacuum pump 10, in particular, two pump rotors, which using a known process allow you to create a vacuum. These pump rotors are located in parallel cylindrical chambers, crossed in the transverse direction, the axes of which lie in the same plane. 1, the plane in which the axes of the pump rotors are located is horizontal. However, you can also provide a pump that has all the other characteristics of the pump shown in figure 2, but in it the plane in which the axis of the pump rotors lie, is inclined at a certain angle to the horizontal plane, or even a pump whose pump rotors are located vertically or below a certain angle to the vertical plane. The rotors can be screw with variable pitch, respectively, with the left turns and with the right turns and rotate, going into each other, in opposite directions in the cylinder 11 (this design of the rotors will be discussed in more detail below). Of course, the present invention is by no means limited to variable pitch augers and the use of constant pitch augers (only part or all of the length of the screw, for example, a “step” auger with a first zone having a first constant pitch and at least at least a second zone having a second constant step different from the first step, or a screw with a first zone having a constant step and a second zone having a variable step), while retaining all the advantages of the present invention.

As for the cylinder 11, it contains, on the one hand, an inner casing and, on the other hand, an outer casing. The inner casing of the cylinder 11 covers two parallel cylindrical chambers that contain rotors. On the one hand, the outer casing of the cylinder 11 covers the inner casing, forming an enclosed space having an inlet and an outlet, and thus ensuring the circulation of a heat exchange fluid. The cylinder 11 is equipped with an inlet 17 for pumped gases and an outlet 18 of gases.

The cylinder 11 rests on the drive housing 12. This drive housing 12 contains, among other things, various components for driving and synchronizing the rotors that support these rotors cantilever and which are designed to support and center the cylinder 11, which will be explained in more detail below.

On the upper part of the crankcase 12, a suspension device 16 is provided. This suspension device 16 comprises a ring 16 'to which a hook (or other similar device) is connected to lift the pump 10 by means of a hoist, for example, to install the pump 10 in a suitable place during the initial installation phase or during maintenance and loading and unloading periods works. Typically, the suspension device 16 is mounted on the crankcase 12 with one or more 16 ”screws that allow the suspension device 16 to be removed when not in use, but of course, a pump 10 can be provided in which the suspension device 16 is not removable, or even a pump 10, which does not have a suspension device.

As shown in figure 1, the rear of the housing 12 is continued by a closed housing 15, which contains the stator of an electric motor. This electric motor drives two of the aforementioned pump rotors, which are located in chambers enclosed by a cylinder 11. In addition, the housing 15 may also comprise electronics for controlling the electric motor, means for visually monitoring the operating parameters of the pump 10 and / or cooling means, although these elements can also located in special housings or in other parts of the vacuum pump 10.

Preferably, the rotor of this electric motor is also mounted cantilever and connected directly to the shaft of one of the pump rotors, on which one of the screws is made (which will be described in more detail with reference to FIGS. 2 and 3). Thus, the rotation of the rotor 40 of the electric motor is transmitted directly to the first pump rotor and through the corresponding transmission mechanism (for example, via a gear transmission) to the second pump pump rotor. At the same time, the engine used can also be a “classic” engine mounted on its own bearings, the rotor of which is connected to the shaft of one of the pump rotors by means of an appropriate coupling coupling.

In these two configurations, the motors used can be synchronous motors (brushless or others), or non-synchronous motors, or any other type of motor. The advantage of using a non-synchronous motor is, in particular, that it can be directly connected to the network. On the other hand, the advantage of synchronous motors is their compactness. The use of a synchronous motor allows, therefore, to further reduce the dimensions of the pump in accordance with the present invention. In addition, synchronous motors are also more economical and have an integrated drive that makes it easy to adjust the speed of rotation depending on the intended application.

Position 13 in figure 1 indicates the support or base, which provides the connection of the cylinder 11 with the floor. For this, the support 13 has legs 14, which can, in particular, be made of soft material other than the material of the support 13, for example, rubber or similar material. These legs 14 may be fixed, but may be adjustable to compensate for possible unevenness of the floor. The number of legs 14 may vary depending on specific needs.

In another embodiment, the vacuum pump 10 in accordance with the present invention, the support 13 may be an integral part of the outer casing of the cylinder, while maintaining all its functions.

Figure 2 presents the vacuum pump 10, shown in figure 1, in section along a plane that passes through the longitudinal axis of the rotors. As can be seen in FIG. 2, the plane that contains the axis of the pump rotors is horizontal. However, as mentioned above, the axis of the pump rotors can also be located in a vertical plane or in a plane having an inclination relative to the horizontal plane and / or relative to the vertical plane.

Figure 2 shows that the pump 10 is a dry screw pump with two pump rotors 20 ', 20 ”. However, it is also possible to use pump rotors of a different type with a similar configuration. Two pump rotors 20 ', 20 ”are enclosed by a cylinder 11 and rotated around their longitudinal axes A1, A2 by an electric motor 40 mounted in the drive housing 15. This electric motor is directly connected to the first pump rotor 20', and then the drive force is transmitted to the second pump rotor 20 "through the corresponding transmission mechanism 21 ', 21" so as to provide synchronous rotation of the two rotors 20', 20 ", but in opposite directions.

The pump rotors 20 ', 20 ”shown in FIG. 2 are screw rotors. The screws 20 ', 20 ”have respectively left turns and right turns and are guided in rotation around their longitudinal axes A1, A2 by the first rotation direction organs 22', 22” and the second direction of rotation organs 23 ', 23 ”. The first 22 ', 22 ”and second 23', 23” direction-of-rotation organs can be, in particular, ball bearings. However, you can use other types of organs of direction of rotation to achieve the same goals.

In the region of the two rotor axes A1, A2, this drive housing 12 is elongated, forming a first elongated bracket 12 'and a second elongated bracket 12 ". It is these brackets 12 ', 12 "containing at their ends the first organs of rotation 22', 22", which together with the second organs of rotation 23 ', 23 "support the rotors 20', 20".

The design of the bodies 22 ', 22 ”, 23', 23” shown in FIG. 2 provides, in particular, a cantilever installation of the rotors 20 ', 20 ”on the drive housing 12. In other words, the rotors 20', 20” are not fixed with side of the entrance 17, which is located on the cylinder 11.

This special design makes it very easy to dismantle the pump 10 and then replace all the elements.

Figure 3 presents a perspective view of a vacuum pump 10 with a cylinder separated from the drive housing and from the base. As shown in figure 3, the cylinder 11 of the pump housing 10 is completely separated from the drive housing 12 and from the base 13. This separation of the cylinder 11 is necessary, in particular, for cleaning the rotors 20 'and 20 "of the pump 10. Due to the cantilever mounting of the rotors 20', 20 ”using bodies 22 ', 22”, 23', 23 ”of the direction of rotation of the cylinder 11 can be easily removed from the base 13, without touching the rotors 20 ', 20”. Since the two brackets 12 ', 12 ”are connected only to the drive housing 12, the absence of a cylinder 11 does not affect the rotors 20', 20”, which can remain stationary, centered and balanced in their original position. In other words, to restart the pump 10, there is no need to adjust the rotors 20 ', 20 ”.

It should be recalled that the use of vacuum pumps in vacuum packaging machines for the food industry should not contradict current standards. The pump 10 in accordance with the invention is a dry pump and, thus, completely eliminates the possibility of contamination of products with oil. Similarly, compared to vacuum pumps with a lubricated impeller, draining and oil processing operations are excluded, which facilitates the operation of such a pump.

Food regulations also require the regular dismantling of the pump for cleaning, inspection or maintenance. Due to the proposed design, specially trained personnel are not required for dismantling.

Thus, the vacuum pump 10 for use in vacuum packaging machines in accordance with the present invention has several advantages that help to improve the use and operation of the vacuum packaging machine in the following ways:

1. saving electric energy:

- relative to a certain cycle time associated with the nature of the pumping process (the degree of internal compression and the change in pitch along the screw);

- through the use of a synchronous motor associated with control electronics (the motor rotor is mounted cantilever on the shaft);

- due to changes in rotor speed depending on the needs of the vacuum packaging machine;

2. space saving:

- by using only one pump instead of commonly used pumping means, and in particular either a vacuum pump with a lubricated impeller integrated in a vacuum packaging machine, or a pump unit containing a vacuum pump with a lubricated impeller located at a distance from the vacuum packaging machine, and a Roots pump type pump integrated in a vacuum packaging machine;

- due to the special arrangement of the axes of the pumping rotors;

- due to the extremely compact design compared to the currently used pumps, associated, inter alia, with a higher rotor speed than the rated speeds of non-synchronous motors, as well as with the absence of a compartment for bearings or gears on the suction side;

3. elimination of the risk of internal contamination of the packaged products with oil coming from a vacuum pump:

- through the use of a dry vacuum pump such as a screw pump;

- due to the lack of a compartment for oil (compartment for bearings or gears) on the suction side;

4. oil saving due to the exclusion of drain operations for the vane vacuum pump;

5. Saving time during cleaning and maintenance procedures:

- due to the external form of the pump, specially designed to comply with hygiene standards of food packaging;

- by facilitating the dismantling of the pump and access to the rotors without draining the oil from the crankcase of the drive gears and without changing the settings of the functional clearances;

- due to access to all service functions from only one side.

It is obvious that the specialist can easily adapt and / or supplement the described characteristics of the vacuum pump using other known elements, without going beyond the scope of the present invention.

Claims (12)

1. A vacuum pump designed for vacuum packaging machines and containing:
- cylinder (11) formed
the casing of two parallel cylindrical chambers intersected in the transverse direction, the axes of which lie in the same plane and one of the sides of which is a wall in which there is a suction hole (17), and
an outer casing covering the casing of two parallel cylindrical chambers, forming an enclosed space having an inlet and an outlet that circulates a fluid that carries out heat exchange,
- two pump rotors (20 ′, 20 ″) located in parallel cylindrical chambers and rotated by the engine, and
- a drive housing (12), which contains a motor, drive and synchronization components of pump rotors, in which the rotors are mounted cantilever and which serves to support and center the cylinder (11), and the pump rotors (20 ′, 20 ″) have first organs (22 ′, 22 ″) directions of rotation and second organs (23 ′, 23 ″) of the direction of rotation of the rotors (20 ′, 20 ″), on which the rotors (20 ′, 20 ″) are mounted cantilever, the first organs (22 ′, 22 ″ ) the directions of rotation are at the ends of two elongated arms (12 ′, 12 ″), which are integral with the drive car ter (12). 2. A pump according to claim 1, characterized in that the back of the crankcase (12) is a closed housing (15), which includes a stator of an electric motor. 3. A pump according to claim 1, characterized in that the housing (15) contains electronic means for controlling the electric motor, means for visually monitoring the operating parameters of the pump (10), and cooling means. 4. The pump according to one of paragraphs. 1-3, characterized in that the electric motor is mounted cantilever, and the rotor of the motor is directly connected to the shaft of one of the pump rotors (20 ′, 20 ″). 5. The pump according to one of paragraphs. 1-3, characterized in that the electric motor has its own thrust bearings, and the rotor of the motor is connected to one of the pump rotors (20 ′) using a coupling connection. 6. The pump according to any one of paragraphs. 1-3, characterized in that it contains a support (13), providing connection to the floor, connecting the cylinder (11) so that the flow of evacuated gases and flushing liquids follow the natural way to the discharge opening (18), producing the effect of a silencer. 7. The pump according to any one of paragraphs. 1-3, characterized in that the support (13) is an integral part of the outer casing of the cylinder (11), while maintaining all its functions. 8. The pump according to any one of paragraphs. 1-3, characterized in that the plane in which the axis of the cylindrical chambers of the pump are horizontal. 9. The pump according to any one of paragraphs. 1-3, characterized in that the suction hole (17) is located on the side of the cylinder (11), opposite the drive crankcase (12), or in the side of the cylinder (11) parallel to the upper side of the support (13). 10. A pump according to claim 1, characterized in that the pump rotors (20 ′, 20 ″) are screw type rotors with left turns and right turns, which rotate in the cylinder (11), going into each other, in opposite directions. 11. A pump according to claim 1, characterized in that the second organs (23 ′, 23 ″) of the direction of rotation are integrated in the drive housing (12). 12. The pump according to claim 1, characterized in that the organs (22 ′, 22 ″, 23 ′, 23 ″) of the direction of rotation are ball bearings.

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