JP2005323642A - High pressure steam sterilization equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high pressure steam sterilization equipment having a simple constitution, easily raising the temperature of a sterile container, effectively using energy, and allowing the inner volume of the sterile container to be designed large. <P>SOLUTION: This high pressure seam sterilization equipment is provided with heat transfer liquid container 4 surrounding the sterile container 2 formed as a pressure vessel, the heat transfer liquid 6 such as silicone oil or the like is stored between the containers 2 and 4, and the container 2 and an object to be sterilized put therein is heated by heating the heat transfer liquid 6 by a heater 8. The user of the heat transfer liquid 6 can raise the inside of the container 2 to a uniform high temperature and is useful for drying the object to be sterilized after the sterilization. A part 12c of a pipe 12 for supplying water to be vaporized by a steam generator 10 is dipped in the heat transfer liquid 6 to quickly lower the temperatures of preheat of raw water to be supplied to the steam generator 10 and of the heat transfer liquid 6 after the drying. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for sterilizing an object to be sterilized such as a medical instrument using high-pressure steam.

  2. Description of the Related Art Conventionally, a high-pressure steam sterilization apparatus that sterilizes an object to be sterilized such as a medical instrument using high-pressure steam (typically saturated steam at 135 ° C. and 0.22 MPa) has been known. In such a sterilization apparatus, an object to be sterilized is contained in a sterilization container, the object to be sterilized is heated, air is further removed from the sterilization container, and then saturated steam is introduced into the sterilization container. The inside is maintained in a saturated steam atmosphere for a predetermined time, whereby the article to be sterilized is sterilized. In the past, an electric heater wrapped around the outer periphery of the sterilization container was used to heat the sterilization container, but from the viewpoint of facilitating temperature control of the sterilization container and equalizing the temperature, The mainstream is to heat a sterilization container by providing a steam jacket and supplying high-temperature steam into the steam jacket. An example of such a sterilization apparatus is described in Patent Document 1.

However, in the above-mentioned conventional apparatus, both the sterilization container and the steam jacket must be designed with strength and corrosion resistance that can withstand steam. For this reason, there is a problem that the manufacturing cost is increased due to the use of an expensive high corrosion resistance material and the structure is complicated, and the weight of the entire apparatus is increased. In recent years, sterilizers are required to have a function to quickly and completely dry sterilized materials. For this purpose, the temperature in the sterilization container during the drying process is sterilized. It is desirable to make it higher than the temperature of the hour. However, in this case, it is necessary to supply high-temperature steam through the steam jacket, and for this purpose, the steam generator is increased in capacity, or a steam generator separate from the steam generator for generating sterilization steam is used. It is necessary to provide it. This leads to a complicated structure of the sterilizer and an increase in manufacturing cost. Further, since the steam supplied into the steam jacket is normally discarded after the role of heating the sterilization container is finished, the heat energy of the steam is wasted. Furthermore, as will be described in detail later, since the size of the sterilization container is limited by legal regulations related to the pressure container, it is difficult to realize a large sterilization container that can process a large amount of objects to be sterilized at one time.
JP 2001-178798 (FIG. 1, paragraph 0014, etc.)

  The present invention has been made in view of the above circumstances, has a simple structure, can easily increase the temperature of the sterilization container, can effectively use energy, and can be designed to have a large internal volume of the sterilization container. An object of the present invention is to provide a high-pressure steam sterilization apparatus.

  In order to achieve the above object, in the present invention, the sterilization container is heated via a liquid heat medium. Furthermore, in the present invention, heat exchange can be performed between water supplied to the steam generator and the liquid heat medium.

  That is, the present invention includes a sterilization container formed as a pressure container capable of loading an object to be sterilized, a liquid heat medium container surrounding the sterilization container, a steam generator for supplying sterilization steam to the sterilization container, There is provided a high-pressure steam sterilizer characterized in that the sterilization container is heated via a liquid heat medium accommodated in the liquid heat medium container.

  Preferably, the high-pressure steam sterilizer according to the present invention further includes a water supply line for supplying water to be vaporized to the steam generator, and a part of the water supply line is in the liquid heat transfer medium container. It is passed through the liquid heat medium container so as to be immersed in the accommodated liquid heat medium, and thereby between the water passing through the water supply pipe and the liquid heat medium in the liquid heat medium container. Heat exchange is possible.

Embodiments of the present invention will be described below with reference to the drawings.
The high-pressure steam sterilizer has a sterilization container 2 formed as a pressure container. The sterilization container 2 is accommodated in the liquid heat medium container 4, and is fixed to the liquid heat medium container 4 by a support member (not shown). A liquid heat medium 6 is accommodated in a space between the sterilization container 2 and the liquid heat medium container 4. The liquid heat medium container 4 simply holds the liquid heat medium 6 therein, and is not a pressure container. The upper opening of the liquid heat medium container 4 is closed by a non-airtight lid 4a, and the pressure in the liquid heat medium container 4 is always substantially equal to the atmospheric pressure.

  An opening (not shown) is formed in a part of the sterilization container 2 so that an object to be sterilized can be taken in and out of the sterilization container 2, and this opening is airtightly closed by a door (not shown). be able to. The liquid heat medium container 4 is also provided with an opening (not shown) at a position corresponding to the opening of the sterilization container 2, and the opening part of the sterilization container 2 and the opening part of the liquid heat medium container 4 are cylindrical members. (Not shown) are connected in such a manner that the liquid heat medium 6 does not enter the cylindrical member. Through this cylindrical member, the object to be sterilized can be taken in and out of the sterilization container 2 without being exposed to the liquid heat medium 6. Since the above structure is not directly related to the gist of the present invention, the illustration is omitted for simplification of the drawing.

  A resistance heating type electric heater 8 (H) is inserted in the space between the sterilization container 2 and the liquid heat medium container 4, and the electric heater 8 is immersed in the liquid heat medium 6 to heat the liquid heat medium 6. To do. In order to make the temperature distribution of the liquid heat medium 6 uniform, it is preferable to provide liquid heat medium stirring means such as an impeller or a stirrer in the liquid heat medium container 4. The electric heater 8 is not necessarily provided in the liquid heat medium container 4. For example, the liquid heat medium container 4 is connected to a liquid heat medium circulation line provided outside the liquid heat medium container 4, and the liquid heat medium An electric heater may be provided in a part of the circulation line. Further, the electric heater 8 may be wound around the outer surface of the liquid heat medium container 4. Furthermore, it is possible to use another appropriate known type of heater instead of the electric heater 8, but it is preferable to use an electric heater in consideration of the ease of temperature control.

  The liquid heat medium 6 can be made of any material as long as it can stably maintain a liquid state at a temperature up to a drying temperature T2 described later. The liquid heat medium 6 is preferably selected from known heat medium oils and used. However, in this embodiment, the liquid heat medium 6 is preferably a silicone oil (specifically, polydimethylsiloxane). ).

  The high-temperature steam sterilization apparatus has a steam generator 10 that generates steam to be supplied to the sterilization container 2, and the steam generator 10 is provided by a heater H (10a) in which water supplied thereto is built. Vaporizes into steam. A raw water tank 14 is connected to the steam generator 10 via a raw water supply pipe 12. The water (purified water) stored in the raw water tank 14 is sent to the steam generator 10 by operating the raw water pressurizing pump 12a (WP). In addition, the code | symbol 12b is a check valve for preventing the backflow of raw | natural water.

  A portion 12 c upstream of the steam generator 10 of the raw water supply pipe 12 is passed through a space between the sterilization container 2 and the liquid heat transfer medium container 4 so as not to contact both the containers 2 and 4. It is immersed in the liquid heat medium 6. In the portion 12 c, heat exchange is performed between the water flowing through the portion 12 c and the liquid heat medium 6. The portion 12 c can be arranged to meander the space between the sterilization container 2 and the liquid heat medium container 4. Alternatively, the portion 12 c can be arranged in a spiral around the sterilization container 2. The portion 12c may be a part of the pipe material forming the raw water supply conduit 12 as described above, but the heat exchanger having a general structure interposed in the pipe material forming the raw water supply conduit 12 (For example, one having an enlarged heat transfer surface).

  The steam generated by the steam generator 10 is supplied to the sterilization container 2 through the steam supply line 16. A steam generator safety valve (relief valve) 16a, a steam flow rate adjustment valve 16b, a solenoid valve (shutoff valve) 16c, and a sterilization container safety valve 16d are provided in this order from the upstream side. An air supply line 18 is connected between the electromagnetic valve 16c and the safety valve 16d in order to purge the sterilization container 2 as necessary. The air supply pipe 18 is provided with a filter 18a and an electromagnetic valve 18b for preventing entry of dust and germs in the air.

  An exhaust / drain pipe 20 is connected to the sterilization container 2. The exhaust / drainage pipe 20 branches into a vacuum exhaust pipe 22, a high-pressure steam exhaust pipe 24, and a steam trap pipe 26. In the vacuum exhaust line 22, an electromagnetic valve 22a, a vacuum pump 22b (VP), and a vacuum exhaust check valve 22c are provided in this order from the upstream side. The high-pressure steam exhaust line 24 is provided with an electromagnetic valve 24a and a check valve 24b in order from the upstream side. The steam trap pipe 26 is provided with a steam trap 26a. The above-mentioned pipelines 22, 24, and 26 merge to form a single exhaust / drainage pipeline 20 again, and communicate with an exhaust / drainage system 28 (generally sewage may be used).

  The exhaust / drain pipe 20 includes, for example, a device from the drain pipe 30 for discharging condensed water from the steam generator 10, the pipe 31 for draining raw water overflowed from the raw water tank 14, and the raw water tank 14. A drain line 32 is connected to discharge raw water that is no longer needed when the operation is stopped. The conduit 30 is provided with an electromagnetic valve 30a and a check valve 30b, the conduit 31 is provided with a check valve 31a, and the conduit 32 is provided with a check valve 32a and a drain valve 32b.

  The raw water tank 14 can be supplied with purified water from a purified water supply source 33. The raw water tank 22 can also receive city water from a city water supply source 34 (which may be a general water supply). The water supplied to the raw water tank 14 can be switched by the water supply switching valve 35. In the water supply line that connects between the raw water tank 14 and the purified water supply source 33, a purified water source valve 36, a water supply switching valve 35, and an electromagnetic valve 37 are provided in this order from the upstream side. In the water supply line connecting the raw water tank 14 and the city water supply source 34, a city water source valve 38, a strainer 39, a pressure gauge 40, a water supply switching valve 35 and an electromagnetic valve 37 are provided in this order from the upstream side. Yes. Furthermore, the city water supply source 34 supplies city water to the vacuum pump 22b in order to evacuate the vacuum pump 22b (VP). In the water supply line connecting the vacuum pump 22b and the city water supply source 44, a city water source valve 39, a strainer 39, a pressure gauge 40, an electromagnetic valve 41, and a constant flow valve 42 are provided in this order from the upstream side. Yes.

  Hereinafter, sensors attached to the sterilization container 2, the liquid heat medium container 4, the raw water tank 14, and the steam generator 20 will be briefly described. Members indicated by reference numerals TIC1, TIC2, TIC3, and TIC4 are temperature sensors with a display function. TIC 1 and TIC 2 indirectly detect the vapor temperature in the sterilization container 2 through the exhaust / drain pipe 20, the TIC 4 detects the temperature of the heater 8, and the TIC 3 detects the temperature of the liquid heat medium 6. The member indicated by the symbol PG attached to the sterilization container 2 is a pressure gauge that displays the pressure in the sterilization container 2, and the member indicated by the symbol PS2 operates when the pressure in the sterilization container 2 exceeds a predetermined value. The member indicated by the pressure switch, symbol PE1, is a pressure sensor that outputs a detection signal corresponding to the pressure in the sterilization container 2. In addition, a member indicated by reference numeral PG attached to the steam generator 10 is a pressure gauge that displays the pressure in the steam generator 10, and a member indicated by reference numeral PS1 indicates that the pressure in the steam generator 10 exceeds a predetermined value. The member indicated by reference numeral BS1 is a bimetal switch that operates when the temperature in the steam generator 10 exceeds a predetermined value. Further, a member denoted by reference numeral FLLS1 attached to the raw water tank 14 is a floatless water level switch for detecting that the water level in the raw water tank 14 has reached the lower limit, and a member denoted by reference numeral LS1 has an upper limit for the water level in the raw water tank 14. It is a water level switch that detects that A controller (not shown) controls members such as a heater, a solenoid valve, and a pump so that an appropriate operation of the sterilizer is realized based on a predetermined processing sequence and detection data obtained by the sensors and switches. .

Next, the operation of the high pressure steam sterilizer having the above-described configuration will be described.
First, the liquid heat medium 6 around the sterilization container 2 is heated to a predetermined temperature, for example, 134 ° C. (hereinafter referred to as “sterilization temperature T1”) by the heater 8. Thereby, the sterilization container 2 itself and the atmosphere in the sterilization container 2 also become the sterilization temperature T1. Next, an object to be sterilized (not shown) is loaded in the sterilization container 2. The sterilization container 2 may be loaded with the material to be sterilized before the liquid heating medium 6 is heated.

  Next, the air in the sterilization container 2 is replaced with steam. First, the electromagnetic valves 16c, 18b, and 24a are closed, and the electromagnetic valve 22a is opened. In this state, the vacuum pump 22b (VP) is operated, and the inside of the sterilization container 2 is depressurized to a predetermined degree of vacuum. Next, the electromagnetic valve 22 a is closed and the electromagnetic valve 16 c is opened, and steam is supplied from the steam generator 10 into the sterilization container 2. Thereby, a high-purity steam atmosphere is established in the sterilization container 2. In addition, when the capability of the vacuum pump 22b is low, the suction of the sterilization container 2 by the vacuum pump 22b and the supply of steam into the sterilization container 2 are repeatedly performed, whereby a high-purity steam atmosphere with a low air concentration is sterilized. 2 can be established. The inside of the sterilization container 2 is filled with saturated steam (for example, steam at 134 ° C. and 0.22 MPa). The steam generator 10 has a steam supply capability sufficient to form a saturated steam atmosphere in the sterilization container 2, for example, a capability of supplying steam at a pressure of 0.3 MPa. For example, the pressure switch PS2 and a solenoid valve A saturated steam atmosphere is maintained in the sterilization container 2 by intermittently supplying steam into the sterilization container 2 in conjunction with 16c. The inside of the sterilization container 2 is maintained in the saturated steam atmosphere for a predetermined time, whereby the article to be sterilized accommodated in the sterilization container 2 is sterilized.

  When the sterilization of the article to be sterilized is completed, the article to be sterilized is dried. That is, first, the electromagnetic valve 24a is opened. Thereby, the vapor | steam in the sterilization container 2 is exhausted through the high pressure steam exhaust pipe 24, and the pressure in the sterilization container 2 falls to substantially atmospheric pressure. Thereafter, the power supplied to the heater 8 is increased, and the temperature of the liquid heat medium 6 maintained at the sterilization temperature T1 (134 ° C.) is increased to a higher predetermined temperature (hereinafter referred to as “drying temperature T2”), for example, 145 ° C. Warm up. The drying temperature may be higher than 145 ° C. as long as the article to be sterilized is not damaged. After the temperature rise, the atmosphere in the sterilization container 2 is sucked in order to promote drying. That is, the electromagnetic valve 24a is closed and the electromagnetic valve 22a is opened, and the vacuum pump 22b (VP) is activated. Thereby, water to be sterilized and water remaining in the sterilization container 2 can be efficiently removed. The article to be sterilized is placed in the above-described high-temperature (drying temperature T2) reduced-pressure atmosphere for a predetermined time. When the drying is completed, the electromagnetic valve 22a is closed and the vacuum pump 22b is stopped. Thereafter, the electromagnetic valve 18b of the air supply line 18 is opened, whereby air is introduced into the sterilization container 2 and the inside of the sterilization container 2 is returned to normal pressure. When the capacity of the vacuum pump 22b is low, it is preferable to alternately perform suction by the vacuum pump 22b and air introduction by opening the electromagnetic valve 18b. Thereby, the water | moisture content in the sterilization container 2 is removed more efficiently.

  When the inside of the sterilization container 2 is returned to normal pressure, the object to be sterilized can be taken out from the sterilization container 2. In addition, when continuing the sterilization process of another to-be-sterilized object after that, after reducing the temperature in the sterilization container 2 to the said sterilization temperature T1, each process mentioned above is performed again. In order to lower the temperature in the sterilization container 2, heat exchange between water and the liquid heat medium 6 in the portion 12 c of the raw water supply pipe 12 can be used.

The sterilization apparatus according to this embodiment has the following advantages.
(1) The liquid heat-medium container 4 should just have the intensity | strength which hold | maintains the liquid heat-medium 6, and does not need to be designed so that it can endure high pressure. For this reason, the liquid heat-medium container 4 can be produced by simple sheet metal processing, leading to a reduction in the manufacturing cost of the sterilization apparatus. Further, the weight of the liquid heat medium container 4 and thus the entire sterilization apparatus can be reduced.

(2) Unlike the case of the conventional sterilization apparatus which heats a sterilization container with the vapor | steam supplied to a vapor | steam jacket, a vapor | steam does not contact the liquid heat-medium container 4. FIG. Therefore, by using a non-corrosive liquid such as silicone oil as the liquid heat medium 6, the liquid heat medium container 4 can be formed of a material having low corrosion resistance, that is, an inexpensive material. In this case, of course, the outer surface of the sterilization container 2 is not required to have high corrosion resistance. For this reason, it is possible to design the sterilization container 2 by using a material that is not so high in corrosion resistance and providing a corrosion-resistant coating on the inner surface of the sterilization container 2. Therefore, the manufacturing cost of the sterilizer can be reduced.

(3) Although steam takes various states depending on temperature and pressure (for example, saturated steam and superheated steam), it is a well-known fact that saturated steam is most suitable for sterilization. In the present embodiment, since the liquid heat medium 6 that is a fluid is used as the heating medium of the sterilization container 2, the wall of the sterilization container 2 is provided in the same manner as a conventional sterilization apparatus that heats the sterilization container with steam supplied to the steam jacket. The body can be heated evenly. This makes it easy to stably maintain the steam in the sterilization container 2 in a desired state (a saturated steam state with high sterilization efficiency).

(4) By using the liquid heat medium 6 as a heating medium for the sterilization container 2, it is easy to raise the temperature of the sterilization container 2 to a drying temperature T2 (eg, 145 ° C.) higher than the sterilization temperature T1 (eg, 134 ° C.). . In a conventional sterilization apparatus that heats a sterilization container with steam supplied to a steam jacket, maintaining the steam at a high temperature such as the drying temperature T2 requires increasing the strength of the steam jacket and increasing the capacity of the steam generator. This leads to a significant increase in the manufacturing cost of the sterilizer. However, according to this embodiment, the inside of the sterilization container 2 can be easily heated to a high temperature without increasing the manufacturing cost of the sterilization apparatus.

(5) The raw water supplied to the steam generator 10 is supplied to the steam generator 10 in a state in which heat is exchanged with the liquid heat medium 6 and preheated in the portion 12c of the raw water supply pipe 12. For this reason, operation | movement of the steam generator 10 can be stabilized. Further, when a plurality of batch processes are continuously performed in the sterilizer, it is necessary to lower the temperature of the liquid heating medium 6 to the sterilization temperature T1 (134 ° C.) after drying and taking out the object to be sterilized. However, since the liquid heat medium 6 has a larger heat capacity than the gas heat medium (steam) used in the prior art, it takes time to lower the temperature if it is simply cooled by natural heat dissipation. However, in this embodiment, since the raw water supply pipe 12 for supplying raw water to the steam generator 10 is immersed in the liquid heat medium 6, the water in the raw water supply pipe 12 and the liquid heat medium 6 are The liquid heat medium 6 can be forcibly and rapidly cooled by heat exchange. For this reason, a plurality of batch processes can be performed in a short time. Moreover, the energy which the liquid heat medium 6 has can be used effectively.

(6) Although related to (5) above, use of the liquid heat medium 6 can reduce energy waste. In other words, in the case of a conventional sterilization apparatus that heats a sterilization container with steam supplied to a steam jacket, high-energy steam after being used for heating the sterilization container is discarded. There is a lot of waste. On the other hand, according to this embodiment, when the liquid heat medium 6 is used, energy is not wasted other than radiant heat from the outer surface of the liquid heat medium container 4. Such energy loss due to radiant heat can be easily reduced, for example, by providing a heat insulating material around the liquid heat medium container 4.

(7) From the viewpoint of safety, the internal volume of the pressure vessel is restricted by law so as to be not more than the value obtained by multiplying the working pressure by a predetermined coefficient. In the case of a conventional sterilization apparatus that heats a sterilization container with steam supplied to the steam jacket, the total volume of the sterilization container and the steam jacket is handled as the internal volume. Will be limited. However, in the sterilization apparatus according to this embodiment, since the liquid heat medium container 4 is not a pressure container, the internal volume of the liquid heat medium container 4 is not included in the internal volume. For this reason, the volume of the sterilization container 2 can be designed large.

The systematic diagram which shows one Embodiment of the high pressure steam sterilization apparatus by this invention.

Explanation of symbols

2 Sterilization container 4 Liquid heat medium container 6 Liquid heat medium 10 Steam generator 12 Water supply line 12c A part of water supply line

Claims (2)

A sterilization container formed as a pressure container capable of loading an object to be sterilized;
A liquid heating medium container surrounding the sterilization container;
A steam generator for supplying sterilization steam to the sterilization container;
With
The high-pressure steam sterilization apparatus, wherein the sterilization container is heated via a liquid heat medium accommodated in the liquid heat medium container. A water supply line for supplying water to be vaporized to the steam generator;
A part of the water supply conduit is passed through the liquid heat medium container so as to be immersed in the liquid heat medium accommodated in the liquid heat medium container, thereby passing through the water supply line. 2. The high-pressure steam sterilization apparatus according to claim 1, wherein heat exchange is possible between the water to be heated and the liquid heat medium in the liquid heat medium container.

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