JP3620875B2 - Operation method of steam sterilizer - Google Patents

Description

[0001]
[Industrial application fields]
The operation method of the steam sterilizer according to the present invention is used when sterilizing patient clothes, used surgical tools, laboratory instruments, and the like in hospitals and various laboratories.
[0002]
[Prior art]
Patient clothing, surgical tools, laboratory equipment, etc. used in hospitals and various laboratories must be sterilized prior to reuse in order to prevent infection by bacteria and viruses attached after use. For this reason, conventionally, steam sterilizers have been used in which sterilization containers are filled with high-temperature and high-pressure water vapor and the objects to be sterilized stored in the sterilization containers are heated and sterilized.
[0003]
FIG. 3 shows a first example of a conventionally known steam sterilizer. The sterilization container 1 can be sealed with a lid (not shown) in a state where an object to be sterilized is housed inside. In the sterilization container 1, one end side of the steam supply pipe 2 is open to a steam generator (not shown) such as a boiler on the other end side (the right side in FIG. 3). A steam supply valve 3 is provided in the middle of the steam supply pipe 2. One end of an exhaust pipe 4 provided with an exhaust valve 5 is connected to the bottom of the sterilization container 1 and the other end is connected to the suction port of the vacuum pump 6.
[0004]
When performing the sterilization operation using the steam sterilizer configured as described above, first, after storing an object to be sterilized in the sterilization container 1, the exhaust valve 5 is opened with the steam supply valve 3 closed. The vacuum pump 6 is operated. Thereby, the inside of the sterilization container 1 becomes a vacuum state. Next, the exhaust valve 5 is closed, the vacuum pump 6 is stopped, the steam supply valve 3 is opened, and high-temperature and high-pressure water vapor is supplied into the sterilization container 1 through the steam supply pipe 2. Send from.
[0005]
Then, by discharging the gas from the sterilization container 1 by the vacuum pump 6 and feeding the high-temperature and high-pressure steam through the steam supply pipe 2 one or more times, the high-temperature and high-pressure steam is put into the sterilization container 1. Fill with. Then, after performing a sterilization operation for a predetermined time with this high-temperature and high-pressure steam, an object to be sterilized is taken out from the sterilization container 1.
[0006]
FIG. 4 shows a second example of a conventionally known steam sterilizer. The sterilization container 1 can be sealed with a lid (not shown) in a state where an object to be sterilized is housed inside. The sterilization container 1 has one end of an exhaust pipe 9 having the other end (the right side in FIG. 4) connected to 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).
[0007]
When performing the sterilization operation using the steam sterilizer configured as described above, first, an object to be sterilized is stored in the sterilization container 1 and then water in the water supply tank is passed into the sterilization container 1 through the water supply pipe. Feed a predetermined amount. The steam heater 7 is energized based on the signal from the controller 13 to heat the water in the sterilization container 1 to generate high-temperature and 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, 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 water vapor is accumulated in the upper part of the sterilization container 1, and the air is pushed down in the lower part. For this reason, the air present in the sterilization container 1 is exhausted through the exhaust pipe 9 by the steam trap 8. Therefore, if the generation of water vapor is continued, only high-temperature water vapor 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 in the sterilization container 1 rise above 100 ° C. and 1 atmosphere. The article to be sterilized stored in the sterilization container 1 is sterilized for a predetermined time by the high-temperature and high-pressure steam.
[0008]
In addition, the surface of the sterilized material after sterilization is wet due to condensation of water vapor. Accordingly, the object to be sterilized is taken out after being dried with warm air or the like.
[0009]
[Problems to be solved by the invention]
By the way, in the case of the structure of the conventional first example shown in FIG. 3, in order to fill the sterilization container 1 with high-temperature and high-pressure steam, high-temperature and high-pressure steam is supplied into the sterilization container 1 by a steam supply device such as a boiler. Before being sent to the vacuum chamber, the inside of the sterilization container 1 is evacuated by operating the vacuum pump 6. For this reason, when a steam sterilizer is configured, a vacuum pump is required, which hinders miniaturization and cost reduction of the steam sterilizer.
[0010]
In the case of the structure of the second conventional example shown in FIG. 4, the air contained in the article to be sterilized stored in the sterilization container 1 is only slowly discharged, and the air is discharged for a considerably long time. Cost.
[0011]
The operation method of the steam sterilizer of the present invention has been invented in view of the above-described circumstances.
[0012]
[Means for Solving the Problems]
The steam sterilizer operated by the operation method of the present invention includes a sterilization container that can be sealed in a state in which an object to be sterilized is stored, a temperature sensor for detecting the temperature in the sterilization container, and a bottom part of the sterilization container. A heater for heating and evaporating the supplied water, an exhaust pipe with its end opened above the water surface on the lower inner surface of the sterilization container, and a series in the middle of the exhaust pipe an opening and closing valve which is is provided with a pressure sensor for detecting the pressure in the sterile container. Further, a controller for controlling energization to the heater and the open / close state of the on-off valve based on signals from the pressure sensor and the temperature sensor is provided.
[0013]
The method of operating a steam sterilizer of the present invention, after supplying water to the bottom sealing the sterile container, by energizing the above heater to evaporate the water in the closed state of the above-off valve, the pressure sensor When the pressure in the sterilization container detected by the sensor reaches a predetermined value, the opening / closing valve is opened, and the pressure sensor is operated to close the opening / closing valve again as the pressure in the sterilization container decreases. This is repeated until the temperature in the sterilization container at the time of detecting is no different from the temperature at the time when the on-off valve was opened last time .
[0014]
[Action]
According to the operation method of the steam sterilizer of the present invention configured as described above, the operation itself when sterilizing the object to be sterilized stored in the sterilization container is the same as that of the conventional steam sterilizer according to the second example described above. Same as the case. In particular, in the steam sterilizer operation method of the present invention, a pressure sensor and a temperature sensor are provided, and the energization of the steam heater and the opening / closing of an exhaust valve provided in the middle of the exhaust pipe are controlled by detection signals from these sensors. ing. Therefore, regardless of the characteristics of the article to be sterilized and the size of the sterilization container, the operation of filling the sterilization container with high-temperature and high-pressure steam for sterilization can be performed quickly.
【Example】
[0015]
FIG. 1 shows a steam sterilizer operated by the operating method of the present invention. Since many parts of the configuration and operation of this steam sterilizer are the same as the structure of the second example of the prior art (FIG. 4) described above, the same parts are denoted by the same reference numerals and duplicated explanations are given. Omitted or simplified, the following description will focus on the features of the present invention.
[0016]
The other end (the right side in FIG. 1) of the exhaust pipe 9 whose one end is opened in the sterilization container 1 is open to the atmosphere. One end of the exhaust pipe 9 is opened on the lower inner surface of the sterilization container 1 in order to exhaust the air in the sterilization container 1. In the middle of the exhaust pipe 9, a pressure sensor 11 and an exhaust valve 12 as an on-off valve are provided in this order from the sterilization container 1 side. The pressure sensor 11 detects the pressure in the sterilization container 1 through the exhaust pipe 9.
[0017]
A temperature sensor 10 for detecting the temperature in the sterilization container 1 is provided inside the sterilization container 1. The controller 13 controls energization of the steam heater 7 and opening / closing of the exhaust valve 12 based on signals from these sensors 10 and 11.
[0018]
When performing the sterilization operation using the steam sterilizer configured as described above, first, an object to be sterilized is stored in the sterilization container 1, and the sterilization container 1 is sealed with a lid (not shown). Then, a predetermined amount of water is sent from the water supply tank (not shown) to the bottom of the sterilization container 1 through a water supply pipe (not shown) with the exhaust valve 12 closed. Next, the steam heater 7 is energized by a signal from the controller 13 to heat and evaporate the water. At this time, the exhaust valve 12 is closed. Steam generated by energization of the steam heater 7 and having a specific gravity smaller than that of 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 of the sterilization container 1 (above the lower surface of the sterilization container 1 and above the water surface). In this way, the pressure in the sterilization container 1 increases while pushing the air downward, and the volume of the air decreases as the pressure increases (Boil's law). Therefore, if the exhaust valve 12 is opened when the pressure in the sterilization container 1 detected by the pressure sensor 11 reaches a predetermined value, the air is exhausted through the exhaust pipe 9.
[0019]
That is, according to the present invention, the steam generated by the energization of the steam heater 7, by utilizing the difference in specific gravity between the air sterilization vessel 1 is compressed concentrate air to the bottom of the sterilization vessel 1, pressure in the sterilization vessel 1 This air is pushed out through the exhaust pipe 9. Then, while energizing the steam heater 7 for generating water vapor in the sterilization container 1, by opening and closing the exhaust valve 12, generation of water vapor in the sterilization container 1 and discharge of air through the exhaust pipe 9 are performed. By repeating (in the case of the invention described in claim 2) , the air in the sterilization container 1 is discharged.
[0020]
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 the pressure sensor 11 rises to a predetermined pressure P '. At that time, the exhaust valve 12 in the middle of the exhaust pipe 9 is opened, and the air accumulated in the lower part of the sterilization container 1 by being pushed down by the water vapor described above is discharged. In this way, the temperature in the sterilization container 1 at the moment when the pressure in the sterilization container 1 reaches P ′ and the exhaust valve 12 is opened is detected by the temperature sensor 10 and stored in the controller 13. Then, the pressure drop in the sterilization container 1 accompanying the discharge of air is detected by the pressure sensor 11, the exhaust valve 12 is closed again, and the steam heater 7 is energized. A certain amount of time elapses due to the hysteresis of the pressure sensor 11 until the exhaust valve 12 is closed again after being opened. That is, as the pressure sensor 11, a sensor having a large hysteresis is used. The discharge of air by opening and closing the exhaust valve 12 performed while energizing the steam heater 7 for generating water vapor is caused by the temperature in the sterilization container 1 at the point of pressure P ′ detected by the temperature sensor 10. This is performed until the pressure P ′ is not changed from the previous time point. That is, while air remains in the sterilization container 1, the temperature in the sterilization container 1 is lower than the saturated vapor temperature at the pressure, whereas when the air runs out, the sterilization container 1 The temperature inside rises to the saturated steam temperature at that pressure. Accordingly, as shown in FIG. 2, when the temperature does not change with respect to the temperature at which the previous pressure P ′ was detected (point a in the figure), the inside of the sterilization container 1 is filled with so-called saturated steam. Will be doing.
[0021]
Accordingly, in 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 energization to the steam heater 7 is continued with the exhaust valve 12 still closed. Then, the inside of the sterilization container 1 is raised to a desired sterilization temperature, and an object to be sterilized stored in the sterilization container 1 is sterilized. When the air is exhausted, the energization of the steam heater 7 may be stopped while the exhaust valve 12 is opened (in the case of the invention described in claim 3) .
[0022]
【The invention's effect】
The operation method of the steam sterilizer according to the present invention is configured and operates as described above, but the air in the sterilization container 1 is stored in the lower part of the sterilization container 1 and is compressed by increasing the pressure to reduce the volume. Discharge in state. Therefore, the air in the sterilization vessel 1 and discharged efficiently in a short time, can meet the sterilization vessel 1 high temperature, at high pressure steam. Moreover, since a vacuum pump is not required, the equipment constituting the steam sterilizer does not increase.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a steam sterilizer operated by the operating method 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 steam sterilizer of a first conventional example.
FIG. 4 is a schematic longitudinal sectional view of the second example.
[Explanation of symbols]
DESCRIPTION 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)

A sterilization container that can be sealed in a state in which an object to be sterilized is stored, a temperature sensor for detecting the temperature in the sterilization container, a heater for heating and evaporating water supplied to the bottom of the sterilization container, and the above An exhaust pipe whose end is opened above the water surface on the lower inner surface of the sterilization container, an on-off valve provided in series in the middle of the exhaust pipe, and the pressure in the sterilization container are detected. And a steam sterilizer operating method comprising a pressure sensor for controlling the power supply to the heater and an open / close state of the on-off valve based on signals from the pressure sensor and the temperature sensor. Then, after sealing the sterilization container and supplying water to the bottom, the heater is energized with the on-off valve closed to evaporate the water, and the pressure in the sterilization container detected by the pressure sensor is opening the on-off valve upon reaching a predetermined value The operation again closes the on-off valve with a decrease in the pressure of the sterile container, the pressure sensor temperature of the sterile container at the time of detecting the predetermined value, and opens the last above-off valve point Steam sterilizer operation method, which is repeated until the temperature in the tank does not change . Opening the on-off valve when the pressure in the sterilization container detected by the pressure sensor reaches a predetermined value while energizing the heater, and closing the on-off valve again as the pressure in the sterilization container decreases The operation method of the steam sterilizer according to claim 1, wherein When the pressure in the sterilization container detected by the pressure sensor reaches a predetermined value, the on-off valve is opened , the energization to the heater is stopped, and the on-off valve is closed again as the pressure in the sterilization container decreases. The steam sterilizer operation method according to claim 1 , wherein energization of the heater is resumed.

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