Pumps – Processes
Reexamination Certificate
1999-12-06
2001-10-23
Freay, Charles G. (Department: 3746)
Pumps
Processes
C417S243000, C417S201000
Reexamination Certificate
active
06305907
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention involves a process for evacuating a wet or liquid conveying medium out of the treatment chamber of a treatment device using a pumping device that has a single or multi-stage suction pump, where the conveying medium is cooled during the evacuation along the flow path such that the conveying medium in the pumping device is in the liquid aggregate state or is converted into that state.
The invention also involves a treatment device for carrying out the above-named process, having a treatment chamber, which is connected to a pumping device for evacuation, and a single or multi-stage suction pump, which is provided for the pumping device, where the pumping device can be cooled at least in a partial area using at least one cooling device such that the conveying medium in the pumping device is found in the liquid aggregate state or is converted into that state.
Furthermore, the invention also contains a single or multi-stage suction pump, especially for the treatment device described above, having at least one intake valve that is located in a pump head and at least one outlet valve, where at least one of these valves has a valve disc that is controlled by the conveying medium and which in the closed position of the valve fits so that it seals on a valve sealing surface of the pump head, which encloses at least one valve opening.
Treatment devices of this type are known for or example, as autoclaves for sterilizing medical items for daily use. These previously known treatment devices have an airtight sealable treatment chamber in which the instruments located therein are exposed prior to sterilization at first to a so-called fractionated pre-vacuum, in which through repeated evacuation of the air in exchange with the periodic incoming flow of steam, an especially good air removal out of the narrow-lumen instruments can also be achieved. During the sterilization operation, the instruments are exposed in the treatment or sterilization chamber to hot water vapor under partial vacuum. In order to quickly dry the instruments after sterilization so that there are no residues, a so-called post-vacuum is in turn created subsequently in the treatment chamber, which shortens the drying times of the sterilizing item and should optimize the drying operation.
For the evacuation, the sterilization chamber of these types of previously known steam sterilization devices is connected to a pumping device, which has a vacuum pump. Due to the impingement of the vacuum pump with water steam, thus far, only water ring pumps or diaphragm pumps have been used. Due to the structural dimensions and the disadvantages of a water ring pump, the smaller steam sterilization devices provided for a doctor's office, for example, usually utilize only diaphragm pumps.
For this reason, a treatment device constructed as a steam sterilizer, of the type noted above, has already been created. It has a pumping mechanism for the evacuation of the treatment or sterilization chamber, which utilizes a suction pump operated in a manner free from water, such that in the suction line provided between the treatment chamber and the suction pump, a water free cooled condenser is connected intermediately in order to convert the conveying medium flowing through the suction line of the pumping device into the liquid aggregate state. (See German Patent DE 44 45 054 C2).
In German Patent DE 44 45 054 C2, it is also described how the treatment chamber of the previously known processing device can be evacuated by opening a solenoid valve and switching on the suction pump at a predetermined pressure at the program start. Then, the solenoid valve is closed and steam is conducted from a steam generator into the pressure chamber until a preset excess pressure is reached. By again opening the solenoid valve and switching on the diaphragm pump, the steam/air mixture is in turn suctioned off to achieve a defined partial vacuum, such that the water vapor coming out of the treatment chamber condenses in a cooling device constructed as a condenser and is collected in a condenser collecting vessel so that the diaphragm pump of the previously known treatment device only pumps air.
In coupling a conventional diaphragm vacuum pump with a conventional autoclave, however, the following problem occurs: After the end of a sterilization operation, the steam is expelled through the vacuum pump via a connection line. In the cold connection line and the cold vacuum pump, at least a part of the steam condenses. This condensate is pumped off by the vacuum pump. It is a problem in this that during the operation in the area of the pump head that is heating up, a re-vaporization of the condensate can occur, so that then a correspondingly larger volume must be pumped off. This takes a considerable amount of time.
A re-vaporization of this type is also not ruled out by the fact that in the suction line provided between the treatment chamber and the suction pump, a condenser is intermediately connected. The problems caused by a re-vaporization of this type also occur, in addition to the autoclaves named at the beginning, for all other types, for example, in treatment devices used for gel drying, out of the processing chamber of which a wet or liquid conveying medium is to be evacuated. Here, a wet conveying medium is understood to be, for example, any gas or gas mixture which transports at least a partial quantity of a substance found in the form of a gas or vapor state or a drippable liquid state.
SUMMARY OF THE INVENTION
The object of the invention is thus to create a process as well as a treatment device of the above-noted type, which allows a rapid and effective pumping out of a wet conveying medium of this type.
In the process of the above-noted type, the solution according to the invention resides especially in that the cooling of the conveying medium is done at least in the area of at least one pump head of the suction pump and/or one connection channel that connects together two pump stages of a multi-stage suction pump, which follow each other in the flow direction, and that the at least one pump head and/or the connection channel of the suction pump is cooled off below the vaporizing or boiling temperature present at the given evacuation pressure.
In the treatment device of the above-noted type, the solution according to the invention resides in particular in that at least one cooling device is provided for cooling at least one of the pump heads of the suction pump and/or one connection channel that connects together two pump stages of a multi-stage suction pump, which follow each other in the flow direction, and that the pump head and/or the connection channel of the suction pump is cooled off using this cooling device in such a manner that the head temperature of the suction pump and/or the inner temperature of the connection channel is cooled off below the vaporizing or boiling temperature present at the given evacuation pressure.
In the objects of the invention described above, the suction pump pulls the wet and, for example, steam-containing conveying medium out of the treatment chamber, such that the steam conducted along with it is compressed when it is moved out in the suction pump at atmospheric pressure and condenses at head temperatures below 100° C. in the pump. This condensate is pumped via the suction pump into the open. In the dead spaces or in the connection line connecting the two adjacent pump stages to each other, however, a residue of the condensate can be left over. Upon a suction stroke, the pressure in the operating space in the suction pump is reduced. At least a part of the condensate that stays in the suction pump could then vaporize if the suction pressure in the vacuum pump were to fall below the vaporizaton pressure corresponding to the head temperature in the pump head at that moment. Such a revaporization of the condensate found in the pump head would, however, lead again to an enlargement of the pumping volume to be pumped off and thus to a reduction of the suction volume as well as
Becker Erich
Riedlinger Heinz
Akin Gump Strauss Hauer & Feld L.L.P.
Freay Charles G.
KNF Neuberger GmbH
LandOfFree
Process for evacuating a wet gas a treatment device to carry... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for evacuating a wet gas a treatment device to carry..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for evacuating a wet gas a treatment device to carry... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2589908