Fluent material handling – with receiver or receiver coacting mea – With soil removing – coating – lubricating – sterilizing and/or... – With cleaning – coating or drying means
Reexamination Certificate
2003-06-30
2004-09-07
Maust, Timothy L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
With soil removing, coating, lubricating, sterilizing and/or...
With cleaning, coating or drying means
C141S069000, C141S082000, C141S085000, C141S091000, C141S105000, C141S283000, C053S425000, C422S306000, C422S307000
Reexamination Certificate
active
06786249
ABSTRACT:
The invention concerns an apparatus for simultaneously sterilizing a multiplicity of packs by means of a gas mixture containing hydrogen peroxide and a carrier gas, comprising
supply lines for the carrier gas and for hydrogen peroxide,
a device for evaporating hydrogen peroxide with heat and for mixing it into the carrier gas,
supply lines and a substantially horizontally extending distributor line, and
nozzles which are arranged above the respective pack and are connected to the distributor line.
It is known for upwardly open packs to be sterilized by introducing a mixture of air and gaseous hydrogen peroxide. With that known process a plurality of packs which are arranged in mutually side-by-side relationship in a row are simultaneously passed under the openings of a corresponding number of nozzles. The sterilization gas mixture is produced by hot air being passed through a porous tubular portion through which completely evaporated hydrogen peroxide is urged from the exterior and then mixed with the air. In addition, to avoid condensation of the sterilization agent, the mixture is passed through a supply and distributor line which is of a double-wall configuration and is charged with hot vapor.
The configuration of the lines with heated tube walls is expensive and difficult and complicated to produce and diffusion of the evaporated hydrogen peroxide in the sintered tubular member into the hot air also involves problems because very high pump pressures are required for the hydrogen peroxide and it is necessary to take precautions to ensure that pores of the right size are not blocked. Clogging of the pores can be expected when small pore sizes are involved while when excessively large pores are used the hydrogen peroxide is only inadequately evaporated.
Therefore the object of the present invention is to simplify the apparatus of the kind set forth in the opening part of this specification and at the same time to provide measures for keeping the concentration of hydrogen peroxide identical at all nozzles over the plurality of packs at a given time.
In accordance with the invention that object is attained in that the distributor line from the upstream location of the in-feed of the conditioned gas mixture to the location of entry upstream of the respective nozzle is in the form of a tubular body containing a longitudinal passage, with at least one substantially tubular heating cartridge extending over the length of the body, and distributed measurement locations, and that the heating cartridge is divided into at least two portions and can be heated controlledly by a supply of electrical energy in such a way that the temperature at the outer ends of the tubular body differs from that at the center and that preferably the temperature at the ends can be adjusted independently from the temperature at the center.
By virtue of the invention, in comparison with the state of the art, it is no longer necessary for the distributor line or indeed also the supply line to be of a double-wall configuration for heating the pipeline by means of passing hot vapor therethrough. It is sufficient to use a longitudinal passage with a heating cartridge which is arranged in the longitudinal direction thereof, in order to build up a given temperature profile in the longitudinal passage. It is understandably easier to provide a single-wall longitudinal passage or to provide same in a tubular body and at the same time arrange heating cartridges there. It has been found that it is also more desirable if the gas mixture, after it has been produced and introduced into the distributor line, is heated in the latter by means of heating cartridges, especially as a temperature profile of the desired magnitude is quite easy to build up, in accordance with the division of the heating cartridge into at least two portions. It was surprisingly found that the temperature of the gas mixture at the distributor line and in particular at the ends thereof causes a variation in the concentration of the peroxide in the gas phase. Therefore it is particularly preferred in accordance with the invention for the temperature at the outer ends of the tubular body to be lower than at the center thereof. By means of suitable heating of the heating cartridge in the center of the tubular body, it is possible to counteract a reduction, that is to say cooling of the gas mixture, at the necessary locations, with the consequence that the temperature at the outer end regions of the tubular body is lower than at the central region thereof, thereby surprisingly achieving both a temperature, which remains the same everywhere, of the gas mixture flowing out of the tubular body, and also a concentration, which remains the same everywhere, of the H
2
O
2
contained therein.
With the sterilization apparatus according to the invention it is possible to simultaneously sterilize 5, 10 or 20 packs, that is to say to act thereon with the sterilization gas through the nozzles. As in the known case the packs to be sterilized are arranged in a row which is preferably in a straight line. The tubular body representing the distributor line then extends over that row of packs, that is to say it is in the form of an elongate rail or an elongate passage. Preferably the gas mixture produced is introduced at the center of the longitudinal extent of the tubular body and the latter is heated in such a way that the temperature of the gas decreases towards the outer ends of the tubular body. The invention provides for heating of the walls of the longitudinal passage in the central region and possibly also the entire tubular body in comparison with the outer ends thereof although the in-feed location of the gas mixture is in the central region. In accordance with the invention that avoids irregular heating and distribution of the concentration of the peroxide in the gas mixture.
In a specific preferred embodiment packs of a capacity of 0.5 liter, 1 liter and 1.5 liters have been respectively sterilized at the same time in tens. The overall volume flow of air for each 10 bottles was between 20 and 30 Nm
3
/h and particularly preferably 22 Nm
3
/h. The temperature of the air should be in the range of between 110° and 150° C. and should particularly preferably be 140° C. 25% hydrogen peroxide was meteredly added in liquid form per cycle, that is to say for each 10 bottles, more specifically for the 0.5 liter pack between 0.5 and 1.0 ml, preferably 0.75 ml; for a 1 liter pack: between 1.0 and 1.5 ml, preferably 1.0 ml; and for a 1.5 liter pack: between 1.75 and 2.5 ml and particularly preferably 2.0 ml. As the volume flow for liquid hydrogen peroxide, a value of between 1.5 and 1.9 ml/s and particularly preferably 1.7 ml/s should be used. The gas concentration was in the range of between 50 and 93 g H
2
O
2
/Nm
3
air and in particular in a desirable example it was 77 g H
2
O
2
/Nm
3
of air.
In an advantageous configuration of the invention the tubular body is in the form of an elongate bar with a strong main body through which centrally passes a longitudinal bore forming the gas passage, with communicating openings to the nozzles, and which on opposite sides of the gas passage and at a spacing in relation to the gas passage is provided with outwardly open grooves for the insertion of a heating cartridge. Production of the distributor line is particularly simple with those measures for a tubular body which is built up in that way can be easily manufactured from a bar-like strong main body. It is only necessary to centrally provide a longitudinal bore in the longitudinal direction of the bar, the bore being provided with communicating openings, corresponding to the number of intended nozzles, transversely with respect to the longitudinal direction of the bar. The nozzles are then fitted in the region of those communicating openings, for example “underneath”, on the tubular body and the main body because the sterilization gases and also other treatment agents in subsequent treatment stations of the overall machine are desirably introduced from above downwardly and, aft
Armbruster Hans
Romer Michael
Sorensen Karsten B.
Wolf Michael
Maust Timothy L.
Stevens & Showalter LLP
Tetra Laval Holdings & Finance S.A.
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