JPS61280863A - Method and apparatus for steady heat-sterilization of packing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the invention (industrial field of application) The present invention relates to a gasket of a rotating shaft and/or a reciprocating shaft, in order to prevent the entry and exit of microorganisms, especially in equipment for carrying out biological processes. A method and apparatus for constant heat sterilization, of the type in which steam condensate flows through a shaft seal.

BACKGROUND OF THE INVENTION Devices are known which use saturated steam and have all the elements placed one after the other in a zone from the steam inlet through the shaft packing to the final condensate outlet.

This type of device requires a very large amount of steam and, furthermore, because of the sequential arrangement of the elements, the condensate that forms flows through the shaft packing only once, so that there is only a small temperature difference between the inlet and the outlet. Only a relatively large amount of heat is transferred correspondingly, so that a large amount of steam is converted into condensate before the shaft packing.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to eliminate the above-mentioned problems, and to provide a method and apparatus for constant heat sterilization of packing, which can be operated more economically and with less loss. be. A further object is to prevent non-condensable vapors from entering the closed chamber and to maintain the temperature of the condensate in the shaft packing at an adjustable temperature below the air temperature of the condensate.

DESCRIPTION OF THE INVENTION The main object of the invention is achieved by circulating at least a portion of the condensate flowing through the packing in a closed circuit.

In this way, steam requirements are reduced and losses are reduced.

The condensate that has flowed through the packing is converted into live steam (especially saturated steam).
Preferably, the mixture is then condensed and returned to the packing once a predetermined temperature has been reached.

By mixing the condensate with live steam, it reaches a temperature sufficient to kill the condensate.

In this case, it is expedient to drain the steam condensate to the outside before reaching a predetermined temperature, thus preventing cold condensate from reaching the shaft packing. If necessary, the temperature of the condensate can be lowered, for example by a heat exchanger, before it is introduced into the shaft packing, so that the frictional heat of the packing can be dissipated from the packing without evaporating the condensed water.

Preferably, the condensate flowing through the packing is circulated by the flow energy of live steam supplied for mixing with the condensate. That is, the live steam heats the condensate to sterilization temperatures and also provides drive. That is, the flow energy of the live steam is utilized for the circulation of the condensate, so that no special pumps are required for said circulation.

However, if necessary, an auxiliary pump driven by the shaft can be provided in the chamber provided with the seal.

A suitable device for carrying out the method is a steam injection pump having one inlet connected to a steam supply conduit, an inlet connected to the outlet of the steam injection pump, and one outlet connected to the inlet of a closed chamber for temperature control. and a mixing vessel with a separate outlet connected to a discharge valve.

That is, the device has two flow paths, a series flow path consisting of the steam injection pump, mixing vessel and discharge valve, and a closed chamber consisting of the steam injection pump, mixing vessel and packing, i.e. a closed chamber and a path from this chamber back to the steam injection pump. It consists of a circulation flow path. A stop valve is provided between the outlet of the mixing container and the discharge valve to prevent excessive thermal stress when heating the shaft gasket from room temperature to sterilization temperature.
It is expedient if the stop valve is provided with a regulating pin which serves to open the stop valve slowly so that the sealing member can be heated gently.

A heat exchanger is provided between the outlet of the mixing container and the inlet of the closed chamber in order to reduce the temperature of the condensed water so that the frictional heat of the condensed water can be taken away from the condensed package and dissipated without causing vaporization of the condensed water. is preferred. If necessary, a pump driven by the shaft can also be provided in the closed chamber to assist the circulation action of the steam injection pump.

(Examples) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

The device 10 consists of an injection pump 12 whose inlet 14 is supplied with live steam (especially saturated steam) via a conduit 16 . The steam injection pump 12 has an outlet 2 of a closed chamber 24 defined in a housing 26 which pivotally supports and guides a shaft 28.
2 is provided with another inlet 18 connected via a conduit 20. A gasket 30 is provided within the sealed chamber 24 to seal the shaft 28 from the inside and outside and to perform constant heat sterilization. For sterilization, approximately 125-t
A temperature of ao'c (often 135°C) is required. Live steam has a suitable pressure for this (approximately +3 bar). The conduit 16 is equipped with a non-return stop before the inlet 14 of the steam injection pump 12 to prevent condensate from being drawn back into the steam supply conduit due to the vacuum created in the steam supply conduit if the steam supply is interrupted for any reason. It is expedient to provide a valve (not shown).

An outlet 32 of the steam injection pump 12 is connected via a conduit 34 to an inlet 36 of a mixing vessel 38 .

It is advantageous to incorporate components (not shown) into the mixing vessel which mix the steam with the condensate and prevent water hammer effects. The mixing container further includes a filling stud 60 and a level gauge 66. The mixing vessel can also be equipped with a temperature display device 62 and a manometer 64.

The mixing vessel 38 has two outlets 40.48, one outlet 40 being connected via a conduit 42 to the condensate discharge vessel 4.
6 and another outlet 48 is connected to the closed chamber 24 via a conduit 50.
It is connected to the entrance 52 of the. The outlet 40 is mounted at a height corresponding to approximately 50% of the filling volume of the mixing vessel 38, and the level gauge 66 has a scale at the height of the outlet 40. The discharge valve 44 may be a so-called thermal condensate discharge mechanism, for example a valve controlled by the temperature of the mixing vessel 88 and optionally operated by external energy.

Conduit 42 between outlet 40 of mixing vessel 38 and discharge valve 44
is expediently provided with a stop valve 54 equipped with an adjusting pin, and the outlet 48 of the mixing vessel 38 and! Closed chamber 24
A heat exchanger 56 is provided in the conduit 50 between the inlet 52 and the conduit 58 for introducing a cooling liquid (for example cooling water). A temperature sensor that can be used to control the function of the heat exchanger 56 is provided directly or in the vicinity of the gasket 30.
For example, a thermocouple (not shown) can be provided.

The operating mode of the device according to the invention will be explained below.

First, the packing 30 is heated to a sterilization temperature. in this case,
In order to avoid thermal stresses and water hammer effects, the heating must not be done abruptly, but must be done for about 10 minutes.

This operation may be accomplished by manual or automatic actuation of a slow or delayed opening stop valve 54. When the gasket 30 is heated, the shaft 28 is in principle stopped.

In this case, the filling stud 60 of the mixing vessel 38 is filled with distilled water or condensate until the scale of the level gauge 66 is reached. In this case, keep the stop valve closed. The inlet 14 of the steam injection pump 12 is then opened and steam is supplied to said pump via the conduit 16. At the same time, or immediately thereafter, the stop valve 54 is slowly opened as described above. Thus, vapor condensate flows through the open stop valve 54, conduit 50 and inlet 52 into the closed chamber 54 and reaches the packing 50;
From this location the steam condensate returns to the steam injection pump 12 via outlet 22 and conduit 20.

The temperature controlled discharge valve 44 closes when a predetermined temperature is reached, i.e. when the condensate reaches a predetermined sterilization temperature.

In this case, a temperature sensor suitably coupled to the discharge valve 44;
For example, thermocouples (not shown) can be provided in the mixing vessel or in the region of the mixing vessel 38.

In this case, the condensate flowing through the closed chamber 24 sterilizes the sealing seal and dissipates the frictional heat generated in the seal during operation and which is not dissipated to the atmosphere by convection.

In another embodiment, the heat dissipation from the packing 30 to the atmosphere is sufficiently large to prevent condensate from heating up, ie, vaporizing.

However, in order to ensure that the frictional heat of the packing can be dissipated without vaporizing the condensate, a heat exchanger 56 is installed in the conduit 50 that can reduce the temperature of the condensate flowing into the closed chamber 24 by cooling water without causing a pressure drop. It is purposeful to connect. In this case, as described above, the heat exchanger 56 can be controlled by a thermocouple provided at or near the packing 30.

Instead of a heat exchanger using cooling water, an air convection cooler can be provided, for example with a slidable insulation jacket. In all cases, it is possible to ensure that the heat exchanger is adapted to the various embodiments and the relevant operating conditions so that the temperature of the condensate in the closed chamber 24 or in the packing 30 is always kept below the vaporization temperature of the condensate. .

When the temperature of the condensate in the mixing vessel 38 falls below a predetermined temperature, i.e. the sterilization temperature, the discharge valve opens again and the mixing vessel 38
The condensate is slowly discharged until the temperature of is returned to a predetermined value.

For example, if the diameter of the shaft 28 is 125 mm and the rotation speed is 100 revolutions/second, approximately 200 to 300 revolutions per hour.
Circulate the little condensate.

That is, in the method according to the present invention, the condensate used for sterilizing the packing 3o is circulated. In this case, the condensate is heated and maintained at the required temperature by live steam and circulated by the flow energy of the steam.

If it is desired to increase or assist the circulating effect of the flowing steam, a suitable pump driven by the shaft 28 can be provided in the closed chamber 30.

That is, according to the present invention, it is possible to wet-sterilize the shaft gasket at the shaft retraction point or withdrawal point of the sealing device. In this case, the temperature of the condensate can be adjusted to the temperature necessary to kill the microorganisms in question.

The heat exchanger allows the temperature of the condensate to be adjusted to a value sufficient to absorb the frictional heat of the packing without vaporization, thus preventing damage to the packing. Furthermore, with a heat exchanger,
On leaving the mixing vessel 38, any remaining uncondensed vapor can be condensed and prevented from entering the closed chamber.

Effects of the invention In the present invention, the condensate water is heated without the use of an auxiliary pump, and several times the amount of condensate produced from the steam is transferred through the shaft packing, thus reducing the temperature at the inlet and outlet. Even if the difference is small, heat exchange can be performed with very little energy consumption.

[Brief explanation of the drawing]

The figure is an explanatory diagram of an apparatus according to the present invention. 10... Sterilizer, 12... Steam injection pump 11,
24... Sealed chamber, 28... Shaft, 3o.
...Patsukin, 38...Mixing container, 44...Discharge valve.

Claims (1)

[Claims] 1. In order to prevent the entry and exit of microorganisms, especially in equipment that carries out biological processes, the packing of the rotating shaft and/or the reciprocating shaft is regularly heat sterilized, and during this heat sterilization, the shaft A method for steady heat sterilization of a packing, characterized in that at least a portion of the condensate flowing through the packing is circulated in a closed circulation path. 2. The condensate that has flowed through the packing is mixed with live steam (especially saturated steam), the mixture is condensed, and when a predetermined temperature is reached, it is returned to the packing. Method for constant heat sterilization of packing. 3. The method for steady heat sterilization of packing according to claim 2, characterized in that the condensate is discharged outside before reaching a predetermined temperature. 4. A method for steady heat sterilization of packing according to claim 2, characterized in that the temperature of the condensate is lowered before feeding it into the packing of the shaft. 5. A method according to any one of claims 1 to 4, characterized in that the condensate flowing through the packing is heated with steam and circulated by flow energy. 6. In a method for constant heat sterilization of a packing, the packing of the shaft is placed in a closed chamber through which condensate flows,
One inlet (14) is connected to the steam supply conduit (16) and another inlet (1) is connected to the outlet (22) of the closed chamber (24).
8) connected to the steam injection pump (12) and the inlet (36) connected to the outlet (32) of the steam injection pump (12), while one outlet is connected to the inlet (52) of the closed chamber (24). (48) is connected to the discharge valve (44) to control the temperature.
) and a mixing container (38) connected to another outlet (40). 7. Outlet (40) and discharge valve (44) of mixing container (38)
7. The device for constant heat sterilization of packings according to claim 6, further comprising a stop valve (54) between the sterilizer and the sterilizer. 8. Outlet (48) of mixing container (38) and closed chamber (
A heat exchanger (56) is provided between the inlet (52) of the packing and the inlet (52) of the packing according to any one of claims 6 and 7. Heat sterilizer. 9. Any one of claims 6, 7 and 9, characterized in that a pump element driven by a shaft (28) is provided in the closed chamber (24). A device for constant heat sterilization of packings as described in 2. 10. Any one of claims 6 to 9, characterized in that the conduit (16) is provided with a check valve in front of the inlet (14) of the steam injection pump (12). The device for constant heat sterilization of packing according to item 1.