JPH0889559A - Steam sterilizer and operating method for the same - Google Patents

Abstract

PURPOSE: To provide the steam sterilizer with which a wide space is not occupied by facilities, further, air can be exhausted and efficiency is improved. CONSTITUTION: This sterilizer is provided with a pressure sensor 11 for detecting pressure inside a sterilized vessel 1 and a temperature sensor 10 for detecting the temperature. Water steam is generated by electrifying a steam heater 7 installed on the bottom of the sterilized vessel 1, an air exhaust valve 12 is opened when the pressure is increased to prescribed pressure, and air pushed down to the lower part of the sterilized vessel 1 is exhausted from an air exhaust pipe 9. After the pressure is reduced, the air exhaust valve 12 is closed. Then, air is repeatedly exhausted by opening and closing the air exhaust valve 12 until the temperature, which is detected by the temperature sensor 10, inside the sterilized vessel 1 at the time point of opening the air exhaust valve 12 stops changing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The steam sterilizer and its operating method according to the present invention are used in hospitals and various laboratories for patient clothes,
Used when sterilizing used surgical tools and experimental instruments.

[0002]

2. Description of the Prior Art Clothes for patients, surgical tools, experimental instruments, etc. used in hospitals and various laboratories must be sterilized before reuse in order to prevent infection by bacteria or viruses attached after use. I won't. Therefore, conventionally, a steam sterilizer has been used in which the sterilization container is filled with high-temperature, high-pressure steam and the object to be sterilized stored in the sterilization container is heat-sterilized.

FIG. 3 shows a first example of a conventionally known steam sterilizer. The sterilization container 1 can be hermetically closed by a lid (not shown) in a state in which an object to be sterilized is stored.
In the sterilization container 1, one end side of the steam supply pipe 2 and the other end side (right side of FIG. 3) are open to a steam generator (not shown) such as a boiler. A steam supply valve 3 is provided in the middle of the steam supply pipe 2. In addition, an exhaust valve 5 is provided in the middle of the bottom of the sterilization container 1.
Is connected to one end of the exhaust pipe 4 and the other end is connected to the vacuum pump 6.
It is connected to the suction port of.

When performing a sterilization operation using the steam sterilizer configured as described above, first, after the object to be sterilized is stored in the sterilization container 1, the steam supply valve 3 is closed and the exhaust valve 5 is opened. Is opened and the vacuum pump 6 is operated. As a result, the inside of the sterilization container 1 is in a vacuum state. Then, the exhaust valve 5 is closed,
The vacuum pump 6 is stopped, the steam supply valve 3 is opened, and high-temperature, high-pressure steam is fed into the sterilization container 1 through the steam supply pipe 2 from a steam supply device such as a boiler.

Then, by discharging the gas from the sterilization container 1 by the vacuum pump 6 and feeding high-temperature, high-pressure steam through the steam supply pipe 2 once or a plurality of times, the sterilization container 1 is exposed to high temperatures. Fill with high-pressure steam.
Then, after sterilization work is performed for a predetermined time with the high temperature and high pressure steam, the object to be sterilized is taken out from the sterilization container 1.

FIG. 4 shows a second example of a conventionally known steam sterilizer. The sterilization container 1 can be hermetically closed by a lid (not shown) in a state in which an object to be sterilized is stored.
The sterilization container 1 is open at one end of an exhaust pipe 9 having the other end (right side in FIG. 4) communicated with the outside air side. A steam trap 8 is provided in the middle of the exhaust pipe 9.
Further, a steam heater 7 is provided at the bottom of the sterilization container 1, and the steam heater 7 can freely heat water sent from a water supply tank (not shown) through a water supply pipe (not shown).

When performing sterilization work with the steam sterilizer configured as described above, first, the sterilization container 1 is filled with the substance to be sterilized, and then the sterilization container 1 is filled with water in the water supply tank. Feed a specified amount through the water supply pipe. Then, based on the signal from the controller 13, the steam heater 7 is energized,
The water in the sterilization container 1 is heated to generate high-temperature, high-pressure steam. On the other hand, a steam trap 8 is provided in the middle of the exhaust pipe 9. By the way, the weight of 1 mol of water vapor is 18 g and the weight of 1 mol of air is 29 g, and the specific gravity of water vapor is smaller than that of air. Therefore, the generated steam accumulates in the upper part of the sterilization container 1 and air is pushed down in the lower part. Therefore, the sterilization container 1 is replaced by the steam trap 8.
The air present therein is exhausted through the exhaust pipe 9. Therefore, when steam generation is continued, only high temperature steam remains in the sterilization container 1. The gas discharge through the steam trap 8 is stopped after the temperature rises, and the temperature and pressure inside the sterilization container 1 rises above 100 ° C. and 1 atm.
The object to be sterilized stored in the sterilization container 1 is sterilized by the high temperature and high pressure steam for a predetermined time.

The surface of the object to be sterilized after sterilization is wet due to condensation of water vapor. Therefore, the object to be sterilized is taken out after being dried with heated air or the like.

[0009]

By the way, in the case of the structure of the first conventional example shown in FIG. 3, in order to fill the interior of the sterilization container 1 with high-temperature and high-pressure steam, a high-temperature steam generator such as a boiler is used. Before the high-pressure steam is fed into the sterilization container 1, the sterilization container 1 is evacuated by operating the vacuum pump 6. For this reason, a vacuum pump is required when constructing the steam sterilizer, which hinders downsizing and cost reduction of the steam sterilizer.

Further, in the case of the structure of the second conventional example shown in FIG. 4, the air contained in the sterilization object housed in the sterilization container 1 is slowly discharged, which is equivalent to the discharge of the air. Takes a long time.

The steam sterilizer and its operating method of the present invention are invented in view of the above-mentioned circumstances.

[0012]

A steam sterilizer according to a first aspect of the present invention is a steam sterilizer that can be sealed in a state in which an object to be sterilized is housed, and a temperature sensor for detecting the temperature in the sterilization container. A heater for heating and evaporating the water supplied to the bottom of the sterilization container, and an exhaust pipe having its end opened at a position above the water surface of the lower inner surface of the sterilization container,
An on-off valve provided in series in the middle of the exhaust pipe and a pressure sensor for detecting the pressure in the sterilization container are provided. Further, the controller is provided with a controller that controls the energization of the heater and the open / closed state of the open / close valve based on signals from the pressure sensor and the temperature sensor.

Further, in the method for operating a steam sterilizer according to a second aspect of the invention, after the sterilization container is closed and water is supplied to the bottom, the heater is energized with the opening / closing valve closed to remove the water. When the pressure inside the sterilization container that is vaporized and detected by the temperature sensor reaches a predetermined value, the on-off valve is released, and the operation of closing the on-off valve again with a decrease in the pressure inside the sterilization container is performed. This is repeated until the temperature in the sterilization container at the time when the pressure sensor detects the predetermined value does not change.

[0014]

With the steam sterilizer of the present invention configured as described above and the method of operating the same, the action itself when sterilizing the object to be sterilized stored in the sterilization container is the same as that of the second conventional example described above. The same as in the case of steam sterilizer. Particularly, in the case of the steam sterilizer of the present invention and its operating method, a pressure sensor and a temperature sensor are provided, and the detection signals from these sensors control the energization of the steam heater and the opening / closing of the exhaust valve provided in the middle of the exhaust pipe. are doing. Therefore, regardless of the characteristics of the object to be sterilized and the size of the sterilization container, the work of filling the sterilization container with high-temperature, high-pressure steam for sterilization can be performed quickly.

【Example】

FIG. 1 shows a steam sterilizer of the present invention. Many parts of the structure and operation of the steam sterilizer of the present invention are the same as the structure of the above-mentioned second conventional example (FIG. 4), and therefore, the same parts are designated by the same reference numerals and overlapped. The description will be omitted or simplified, and the characteristic portions of the present invention will be mainly described below.

The other end (right side in FIG. 1) of the exhaust pipe 9 having one end opened in the sterilization container 1 is open to the atmosphere. One end of the exhaust pipe 9 is opened to the inner surface of the lower portion of the sterilization container 1 in order to discharge the air inside the sterilization container 1. A pressure sensor 11 and an exhaust valve 12, which is an opening / closing valve, are provided in the exhaust pipe 9 in this order from the sterilization container 1 side. The pressure sensor 11 detects the pressure in the sterilization container 1 via the exhaust pipe 9.

A temperature sensor 10 for detecting the temperature in the sterilization container 1 is provided inside the sterilization container 1. The controller 13 controls the energization of the steam heater 7 and the opening / closing of the exhaust valve 12 based on the signals from the sensors 10 and 11, respectively.

When performing a sterilization operation using the steam sterilizer configured as described above, first, the object to be sterilized is stored in the sterilization container 1, and the sterilization container 1 is closed with a lid (not shown). A predetermined amount of water is supplied from the water supply tank (not shown) with the exhaust valve 12 closed.
Through the bottom of the sterilization container 1. Then, the controller 1
A signal from 3 energizes the steam heater 7 to heat and evaporate this water. At this time, the exhaust valve 12 is closed. The steam generated by the energization of the steam heater 7 and having a smaller specific gravity than air gradually accumulates in the upper part of the sterilization container 1.
Then, the air existing in the sterilization container 1 is pushed down to the lower part inside the sterilization container 1 (inside the lower part of the sterilization container 1 above the water surface of the water). In this way, the pressure in the sterilization container 1 rises while pushing the air downward, and the volume of air decreases with the increase in pressure (Boyle's law). Therefore, if the exhaust valve 12 is opened when the pressure inside the sterilization container 1 detected by the pressure sensor 11 reaches a predetermined value, this air is exhausted through the exhaust pipe 9.

That is, according to the present invention, the air is compressed and concentrated in the lower portion of the sterilization container 1 by utilizing the difference in specific gravity between the water vapor generated by energization of the steam heater 7 and the air in the sterilization container 1,
This air is pushed out through the exhaust pipe 9 by the pressure in the sterilization container 1. Then, while the steam heater 7 for generating steam in the sterilization container 1 is energized, the exhaust valve 12 is opened and closed to generate steam in the sterilization container 1 and discharge air through the exhaust pipe 9. By repeating the process, the air in the sterilization container 1 is discharged.

More specifically, as shown in FIG. 1, a pressure sensor 11 is provided in the middle of the exhaust pipe 9, and the pressure P in the sterilization container 1 detected by this pressure sensor 11 is a predetermined value P. When the temperature rises to ′, the exhaust valve 12 in the middle of the exhaust pipe 9 is opened, and the air that has been pushed down by the above-mentioned steam and accumulated in the lower part of the sterilization container 1 is discharged. In addition, the temperature inside the sterilization container 1 at the moment when the pressure inside the sterilization container 1 reaches P ′ and the exhaust valve 12 is opened in this way is detected by the temperature sensor 10 and stored in the controller 13. Then, the pressure drop in the sterilization container 1 due to the discharge of the air is detected by the pressure sensor 11 described above.
And the exhaust valve 12 is closed again and the steam heater 7 is detected.
Energize. A certain amount of time elapses due to the hysteresis of the pressure sensor 11 before the exhaust valve 12 is opened and then closed again. That is, the pressure sensor 11 has a large hysteresis. The discharge of air by opening and closing the exhaust valve 12 while keeping the steam heater 7 energized to generate water vapor is detected by the temperature sensor 10 at the temperature inside the sterilization container 1 at the time P '. The process is repeated until there is no change from the time when the pressure P'was previously detected. That is, while the air remains in the sterilization container 1, the temperature inside the sterilization container 1 becomes lower than the saturated vapor temperature at the pressure.
When the air is exhausted, the temperature inside the sterilization container 1 rises to the saturated vapor temperature at the pressure. Therefore, as shown in FIG. 2, when the above temperature does not change with respect to the temperature at the time when the previous pressure P'is detected (point a in the figure), the sterilization container 1 is filled with so-called saturated steam. You are doing it.

Therefore, according to the present invention, after the sterilization container 1 is filled with saturated steam by energizing the steam heater 7 and discharging excess air as described above, the steam heater 7 is further supplied with the exhaust valve 12 closed. The energization is continued to raise the sterilization container 1 to a desired sterilization temperature, and the sterilization object stored in the sterilization container 1 is sterilized. It should be noted that during the air discharge, the power supply to the steam heater 7 may be stopped while the exhaust valve 12 is open.

[0022]

The steam sterilizer of the present invention and the operating method thereof are as follows.
Although constructed and operated as described above, the air in the sterilization container 1 is stored in the lower part of the sterilization container 1 and is compressed by the increase in pressure and discharged in a state where the volume is reduced. Therefore, the air in the sterilization container 1 can be efficiently discharged in a short time, and the interior of the sterilization container 1 can be filled with high-temperature, high-pressure steam. Moreover, since a vacuum pump is not required, the equipment constituting the steam sterilizer does not become bulky.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing a steam sterilizer of the present invention.

FIG. 2 is a diagram showing the temperature in the sterilization container at the moment when the on-off valve is closed by the pressure sensor.

FIG. 3 is a schematic vertical sectional view showing a first conventional steam sterilizer.

FIG. 4 is a schematic vertical sectional view of the second example.

[Explanation of symbols]

 1 Sterilization container 2 Steam supply pipe 3 Steam supply valve 4 Exhaust pipe 5 Exhaust valve 6 Vacuum pump 7 Steam heater 8 Steam trap 9 Exhaust pipe 10 Temperature sensor 11 Pressure sensor 12 Exhaust valve 13 Controller

Claims (3)

[Claims] 1. A sterilization container which can be hermetically sealed while containing a substance to be sterilized, a temperature sensor for detecting the temperature in the sterilization container, and for heating and evaporating water supplied to the bottom of the sterilization container. Heater, an exhaust pipe whose end is opened at a position above the water surface of the lower inner surface of the sterilization container, an on-off valve provided in series in the middle of the exhaust pipe, and the sterilization container Steam sterilization including a pressure sensor for detecting the internal pressure, and a controller that controls the energization of the heater and the open / closed state of the on-off valve based on signals from the pressure sensor and the temperature sensor. vessel. 2. A sterilization container which can be hermetically sealed in a state where an object to be sterilized is housed therein, a temperature sensor for detecting the temperature in the sterilization container, and for heating and evaporating water supplied to the bottom of the sterilization container. Heater, an exhaust pipe whose end is opened at a position above the water surface of the lower inner surface of the sterilization container, an on-off valve provided in series in the middle of the exhaust pipe, and the sterilization container Steam sterilization including a pressure sensor for detecting the internal pressure, and a controller that controls the energization of the heater and the open / closed state of the on-off valve based on signals from the pressure sensor and the temperature sensor. A method of operating a container, wherein after sterilizing the sterilization container and supplying water to the bottom, the heater is energized to evaporate the water with the on-off valve closed, and sterilization detected by the temperature sensor. When the pressure in the container reaches the specified value, The operation of releasing the on-off valve and closing the on-off valve again with the decrease in pressure in the sterilization container,
Repeatedly until the temperature in the sterilization container at the time when the pressure sensor detects the predetermined value does not change,
How to operate a steam sterilizer. 3. When the pressure inside the sterilization container detected by the temperature sensor reaches a predetermined value, the on-off valve is released and the heater is de-energized, and the pressure inside the sterilization container is reduced again. The method for operating a steam sterilizer according to claim 2, wherein the on-off valve is closed and the energization of the heater is restarted.