JP2015188602A - steam sterilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam sterilizer not generating a problem of a sound or the like in vacuum drawing, capable of starting an operation surely, and transferring to a next operation, in a vacuum drawing step performed before a sterilization step.SOLUTION: Control means 34 of a steam sterilizer 1 controls vacuum drawing means 30 so that an operation is started when a value of pressure change in a chamber 11 exceeds a threshold.

Description

  The present invention relates to a steam sterilizer that performs sterilization processing on an object to be sterilized such as a surgical instrument with high-pressure steam.

  As a steam sterilizer for performing sterilization using high-pressure steam on an object to be sterilized such as a medical instrument, for example, a steam sterilizer described in Patent Document 1 is known. In the steam sterilizer described in Patent Document 1, vacuuming is performed several times for the purpose of reducing the air in the chamber as much as possible before the sterilization process.

  Here, in the steam sterilization apparatus described in Patent Document 1 below, evacuation is started immediately after the supply of saturated steam (hereinafter also referred to as steam) is completed. However, after the vapor is supplied, the pressure in the chamber is high, and even if the pump is not operated, the gas in the chamber is exhausted by simply opening the valve. Rather, the vacuum pump is turned on when the pressure in the chamber is high. When operated, there was a problem that intense sound was generated from the vacuum pump.

  Therefore, in a steam sterilizer that performs evacuation, after the supply of saturated steam into the chamber is completed, the valve is opened to discharge the gas in the chamber, and the vacuum pump is operated after the pressure in the chamber drops to some extent. Control is normally performed.

JP 2010-253036 A

  In the steam sterilizer described in Patent Document 1, the pump operation when air is discharged is controlled in the evacuation process after the pressure in the chamber drops below a predetermined pressure. However, if the pump operation is controlled based on the predetermined pressure, the pump operation is not started and the next operation cannot be started when the pressure in the chamber does not drop to the predetermined pressure. On the other hand, if the predetermined pressure is set high, the above-described problem that a violent sound is generated from the vacuum pump occurs.

  Accordingly, the present invention provides a steam sterilizer that can reliably start operation and move to the next operation without causing problems such as sound in the evacuation process performed before the sterilization process. With the goal.

  In order to achieve the above object, a first aspect of the present invention includes a chamber having an opening for taking in and out an object to be sterilized, a water storage tank in which water before use is stored, and waste water in which water after use is stored. A tank, a heating means provided between the water storage tank and the chamber, for heating the water from the water storage tank to generate steam; a drainage channel connecting the chamber and the drainage tank; Measured by the vacuum evacuation means provided in the drainage channel for sucking water and steam in the chamber and discharging them to the drainage tank, the pressure measurement means for measuring the pressure in the chamber, and the pressure measurement means Control means for controlling the operation of the evacuation means based on the pressure in the chamber, wherein the control means has a value of a change in pressure in the chamber exceeding a threshold value. And controlling the evacuating means so as to initiate the operation to.

  According to the first aspect of the present invention, since the control means controls the operation of the evacuation means to start according to the value of the pressure change in the chamber, the sterilization process proceeds without stopping. Also, no noise is generated during evacuation.

  Further, a second aspect of the present invention is the steam sterilizer according to the first aspect, wherein the control means has an absolute value of a rate of change in pressure in the chamber with respect to a predetermined time being lower than a predetermined value. The evacuation means is controlled to start operation sometimes.

  According to the second aspect of the present invention, by setting the change in pressure in the chamber with respect to time as a threshold value, the pressure in the chamber is in an equilibrium state and evacuation can be started, and the exhaust in the chamber is efficiently performed. Well done.

  A third aspect of the present invention is the steam sterilizer according to the first aspect, further comprising a cooling means between the chamber of the exhaust passage and the evacuation means. It is characterized by that.

  According to the third aspect of the present invention, since the steam and air exhausted from the chamber are cooled, the temperature of the fluid discharged to the drain tank is lowered, and there is no sound discharged to the drain tank.

  According to a fourth aspect of the present invention, there is provided a steam sterilizer according to the first aspect, wherein the evacuation means sucks a fluid from one side and discharges the fluid to the other side. It is characterized by comprising an ejector having an inflow port into which the fluid to be discharged flows in, an outflow port from which the fluid flows out, and a suction port into which another fluid is sucked.

  According to the 4th aspect of this invention, a steam sterilizer can be produced more cheaply by using the combination of an inexpensive pump and ejector as a vacuum drawing means.

  Further, a fifth aspect of the present invention is the steam sterilizer according to the fourth aspect, wherein the exhaust flow path is configured to discharge the fluid from the chamber to the drain outlet and the drain tank. A discharge port for discharging, a supply port for supplying water from the drainage tank, a first flow path for connecting the discharge port and the suction port, and a second flow for connecting the discharge port and the discharge port And a third flow path connecting the supply port and the inflow port, and water is supplied from the water supply port side between the supply port and the inflow port as the third flow path. The pump for sucking and flowing water to the inlet side is provided.

  According to the fifth aspect of the present invention, water stored in the drainage tank can be reused as water supplied from the pump to the ejector.

It is a schematic side view of the steam sterilizer which concerns on embodiment of this invention. It is a graph which shows the change of the pressure with respect to time in the chamber in the sterilization process in the steam sterilizer concerning the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiment described below exemplifies a steam sterilizer for embodying the technical idea of the present invention, and is not intended to specify the present invention as this steam sterilizer. The present invention is equally applicable to other embodiments within the scope of the claims.

  First, with reference to FIG. 1, the steam sterilizer 1 which concerns on embodiment of this invention is demonstrated. FIG. 1 is a schematic side view of a steam sterilizer 1 according to an embodiment of the present invention.

  The steam sterilizer 1 includes a chamber 11 inside a main body case 10. The chamber 11 has a hollow cylindrical shape having an opening 12. The chamber 11 is made of a material having high corrosion resistance, and is specifically made of stainless steel of SUS304. The opening 12 is positioned on the side surface of the main body case 10, and the user inserts and removes an object to be sterilized (for example, a medical instrument) to be sterilized through the opening 12. Further, the opening 12 is closed by an openable / closable lid 13 with a handle during the sterilization operation. In addition, when the article to be sterilized is accommodated, a mounting shelf (not shown) on which the article to be sterilized is placed is detachably installed inside the chamber 11.

  Further, the steam sterilizer 1 includes a water storage tank 14 inside the main body case 10. The water storage tank 14 is for storing water used for generating steam used in the sterilization process. Then, prior to the sterilization work of the article to be sterilized, the operator opens the top side lid (not shown) of the main body case 10 and is supplied to the water storage tank 14.

  Further, the steam sterilizer 1 includes a block boiler 15 as a heating means inside the main body case 10. The block boiler 15 is for generating steam for heating water to sterilize the sterilizer. The block boiler 15 includes a water flow path through which water flows and a sheathed heater 16.

  A water supply pipe 19 is connected between the water storage tank 14 and the block boiler 15 via an electromagnetic valve 17, an electromagnetic pump 18 and a check valve 21. The water supply pipe 19 is used to supply water from the water storage tank 14 to the block boiler 15. By opening the electromagnetic valve 17 and operating the electromagnetic pump 18, the water in the water storage tank 14 is supplied to the water supply pipe 19. Is supplied to the block boiler 15. The check valve 21 is a valve for stopping the flow of gas or the like from the block boiler 15 to the pump.

  The chamber 11 and the block boiler 15 are connected by a steam supply tube 20. The steam supply pipe 20 is used to supply steam generated in the block boiler 15 to the chamber 11.

  The connection point A between the steam supply pipe 20 and the chamber 11 may be anywhere in the chamber 11, but in the present embodiment, the steam supply pipe 20 is connected above the chamber 11, and the air By supplying steam having a higher specific gravity than the upper part, the air in the chamber 11 is efficiently pushed out of the chamber 11.

  An air supply pipe 22 is connected to the chamber 11. The air supply pipe 22 is used for taking in air supplied into the chamber 11 from the outside of the steam sterilizer 1 in a drying process described later. A filter 24, an air valve 25 composed of an electromagnetic valve, and a reverse valve 23 are sequentially connected to the air supply pipe 22. Then, by opening the air valve 25, the taken-in air is purified by the filter 24, supplied to the chamber 11 through the air supply pipe 22, and used for drying the object to be sterilized and the chamber 11.

  Further, the steam sterilizer 1 includes a drain tank 26 that stores water used for sterilization of an object to be sterilized in the chamber 11 inside the main body case 10. A drain pipe 27 is connected between the chamber 11 and the drain tank 26. The drain pipe 27 is used to send moisture or the like accumulated in the chamber 11 to the drain tank 26. The drain pipe 27 includes a pressure safety valve 28 in front of the drain tank 26. The pressure safety valve 28 is a valve that is opened when draining from the chamber 11 to the drain tank 26.

  Further, between the chamber 11 and the drainage tank 26, an exhaust passage 29 for exhausting fluid such as air and steam in the chamber 11 through an exhaust valve 29 constituted by an electromagnetic valve and a vacuum evacuation means 30. The exhaust pipe 31 is connected.

  The evacuation means 30 is composed of a pump 40 that sucks fluid from one side and discharges fluid from the other, and an ejector 41 that sucks other fluid using the venturi effect of the fluid discharged from the pump 40. Yes.

  In the present embodiment, a line pump is used as the pump 40. The ejector 41 has an inflow port 41c into which the fluid discharged from the pump 41 flows in, an intake port 41a into which the gas or vapor in the chamber 11 which is another fluid is sucked, and an outflow port 41b from which the fluid flows out. The inflow port 41c and the outflow port 41b are provided on the same straight path, and the suction port 41a is provided so as to be orthogonally connected thereto.

  On the path connecting the inflow port 41c and the outflow port 41b of the ejector 41, the portion where the suction port 41a is orthogonally connected is thinner than the other paths. For this reason, when the pump 40 discharges water, which is a fluid supplied from the outlet 31c, to the inlet 41c of the ejector 41, and the introduced water flows out into the outlet 41b through the inside of the ejector 41, Due to the Venturi effect, air or vapor in the chamber 11 flowing through the first flow path is sucked from the suction port 41a and flows out to the outflow port 41b.

  In the present embodiment, a combination of a pump and an ejector as the evacuation means 30 is used as an alternative to an expensive vacuum pump. However, instead of a combination of a pump and an ejector, a vacuum pump may be used for the evacuation means 30, or another pump may be used.

  The exhaust pipe 31 supplies the fluid to the exhaust port 31 a for exhausting fluid such as air and steam in the chamber 11, the exhaust port 31 b for discharging fluid to the drain tank 26, and the vacuuming means 30. An outlet 31c, a first channel connecting the outlet 31a and the suction port 41a, a second channel connecting the outlet 31b and the outlet 41b, and the outlet 31c and the flow And a third flow path connecting the inlet 41c.

  The outlet 31a is connected to the back wall of the chamber 11, the outlet 31b is connected to a position higher than the maximum water level when water is stored in the drain tank 26 to the maximum, and the outlet 31c is It is connected to the lower surface of the drain tank 26. In the present embodiment, the outlet 31c is connected to the lower surface of the drainage tank 26 in order to reuse the drainage, but may be connected to the lower surface of the water storage tank 14, or the water storage tank 14 and the drainage tank 26. Separately, a tank for supplying fluid to the vacuuming means 30 may be further provided.

  A cooling means 42 for cooling the steam and air exhausted from the chamber 11 is attached to the first flow path of the exhaust pipe 31. A check valve 43 is provided between the cooling means 42 and the vacuuming means 30. If the steam and air exhausted from the chamber 11 are discharged to the drain tank 26 without being cooled, the water temperature in the drain tank 26 rises, and the vacuum and the air cannot be sucked by the evacuation means 30. For this reason, the steam and air exhausted from the chamber 11 are cooled by the cooling means 42, and the water and the cooled air that are cooled by the evacuation means 30 are discharged to the drain tank 26. In the present embodiment, a cooling fan and a radiator are used as the cooling means 42.

  Further, a pressure measuring means 32 constituted by a pressure gauge is attached to the upper surface wall of the chamber 11. Then, the internal air pressure of the chamber 11 is measured by the pressure measuring means 32. In this embodiment, a semiconductor pressure sensor is used as the pressure gauge, but any pressure sensor can be used as long as it can measure the atmospheric pressure in the chamber 11.

  In addition, a temperature sensor 33 composed of a thermistor is attached to the back wall of the chamber 11. Then, the internal temperature of the chamber 11 is measured by the temperature sensor 33.

  Further, the steam sterilizer 1 includes a control unit 34 inside the main body case 10. The control unit 34 is configured by a microcomputer or the like, and the control unit 34 and the induction coil 17 are connected by a wiring 35 (shown by a broken line). Control is performed based on preset programs, outputs from the air pressure measuring means 32 and the temperature sensor 33, and user operations via an operation unit (not shown) provided in the main body case 10. The unit 34 performs heating of the sheathed heater 16, operation control of the electromagnetic pump 18 and the vacuuming means 30, and opening / closing control of the electromagnetic valves 17 and 28, the air valve 25, and the exhaust valve 29.

  An example of a series of steps for performing sterilization using the steam sterilizer 1 configured as described above will be described with reference to FIGS. 1 and 2. In addition, FIG. 2 is a graph which shows the change of the pressure with respect to the time in the chamber in the sterilization process in the steam sterilizer which concerns on embodiment of this invention.

  First, the operator places an object to be sterilized on a placement shelf in the chamber 11 and closes the lid 13. Next, when the operator operates the operation unit provided on the front surface of the main body case 10 and starts the operation of the steam sterilizer 1, the control unit 34 starts to supply current to the sheathed heater 16, and the block boiler 15 Generates heat. Then, the electromagnetic valve 17 is opened and the electromagnetic pump 18 is operated by the control unit 34, and water is supplied from the water storage tank 14 into the block boiler 15 through the water supply pipe 19.

  And water is heated in the heated block boiler 15, and a vapor | steam is generated. And this vapor | steam passes the steam supply pipe | tube 20, and is supplied in the chamber 11 from the connection location A (heating process). At this time, the control unit 34 opens the exhaust valve 29 and at the same time, the control unit 34 starts timing. Immediately after the exhaust valve 29 is opened, the pressure in the chamber 11 is higher than the atmospheric pressure, and the gas in the chamber 11 passes through the first flow path without being operated by the evacuation means 30, and is cooled by the cooling means 42. Exhaust and drain through the two flow paths to the drain tank 26 (exhaust process). When the evacuation means 30 is operated in a state where the pressure in the chamber 11 is high, the steam and air in the chamber 11 exhausted through the first flow path are not sufficiently cooled by the cooling means 42 and are discharged as steam. It will be discharged to the tank 26. If the steam is discharged into the drain tank 26, a loud noise will be produced.

  For this reason, the evacuation means 30 has the value of the pressure in the chamber 11 measured by the pressure measurement means 32 with respect to the time measured by the control unit 34 as indicated by the slope of the broken line L shown in FIG. When the absolute value of the ratio of the change falls below a predetermined value, the control unit 34 starts the operation. At this time, the pump 40 in the evacuation means 30 is driven and the water in the drain tank 26 is sent to the ejector 41 so that the fluid cooled by the cooling means 42 passes through the first flow path of the exhaust pipe 31. The air is sucked in from the suction port 41a of the ejector 41, is discharged from the outlet 41b of the ejector 41 together with the water fed by the pump 40, and is exhausted and drained to the drain tank 26 (evacuation step). The evacuating means 30 is operated until the pressure in the chamber 11 is measured by the pressure measuring means 32 until a predetermined pressure (-0.07 megapascal in this embodiment) is measured, and the pressure in the chamber 11 becomes the predetermined pressure. The operation ends when

In this embodiment, the operation of the evacuation means 30 is started at a rate of pressure change with respect to a predetermined time, but in addition to this, the pressure change amount is integrated, the difference from the predetermined value is integrated, and the difference is integrated. When the amount exceeds the set value, the control unit 34 may control the evacuation unit 30 to start the operation.

  The venting step and the vacuuming step are performed a plurality of times, and the atmosphere filled in the chamber 11 when the object to be sterilized is placed is exhausted from the chamber 11. In this embodiment, it is performed three times. Then, when the temperature in the chamber 11 reaches a certain temperature while monitoring the output of the temperature sensor 33, the exhaust valve 29 is closed and the evacuation means 30 is stopped by the control unit 34. Then, steam is continuously supplied, and the inside of the chamber 11 becomes a high pressure state. When the inside of the chamber 11 reaches the sterilization temperature (usually 121 ° C.), sterilization processing is performed for a predetermined time (usually 20 minutes) (sterilization process). The temperature control in the chamber 11 during the sterilization process is performed by the output of the temperature sensor 33, the opening of the exhaust valve 29, and the operation of the evacuation means 30.

  When the predetermined time elapses and the sterilization process is completed, the supply of water into the block boiler 15 and the supply of current to the sheathed heater 16 are stopped, and then the exhaust valve 29 is opened by the control unit 34. By opening the exhaust valve 29, the inside of the chamber 11 in a high pressure state is opened to the atmosphere at once (atmospheric release step). Then, much of the water remaining in the chamber 11 is discharged to the drain tank 26 at a stretch.

  When the atmosphere release process is completed, the vacuuming means 30 is then operated by the control unit 34, whereby the air and the like in the chamber 11 are discharged through the exhaust pipe 31. And the inside of the chamber 11 is made into a negative pressure state by the air in the chamber 11 being discharged. Note that the sterilized product is dried by keeping the inside of the chamber 11 in a negative pressure state. When the evacuation for a predetermined time is completed, the control unit 34 opens the air valve 25 and supplies the air from the air supply pipe 22 into the chamber 11 through the filter 24 (drying process).

  A series of processes for performing sterilization using the steam sterilizer 1 in the present embodiment is completed by the processes as described above.

In addition, the steam sterilizer 1 of the present embodiment has a configuration (so-called horizontal type) in which the opening 12 of the chamber 11 faces the side surface of the main body case 10 and a lid 13 is provided on the side surface of the main body case 10. For example, a configuration (so-called vertical type) in which an opening and a lid of a chamber are arranged on the upper surface of the main body case is also possible.

DESCRIPTION OF SYMBOLS 1 ... Steam sterilizer 10 ... Main body case 11 ... Chamber 12 ... Opening 14 ... Water storage tank 15 ... Block boiler 16 ... Seed heater 19 ... Water supply pipe 20 ... Steam supply pipe 21 ... Check valve 22 ... Air supply pipe 26 ... Drain tank 27 ... Drain pipe 30 ... Vacuum pulling means 31 ... Exhaust pipe 32 ... Pressure measuring means 34 ... Control unit 40 ... Pump 41 ... Ejector 42 ... Cooling means

Claims (5)

A chamber having an opening for taking in and out the article to be sterilized;
With a water storage tank that stores water before use,
A drainage tank for storing used water,
A heating means provided between the water storage tank and the chamber, for heating the water from the water storage tank to generate steam;
An exhaust passage connecting the chamber and the drainage tank;
Vacuuming means provided in the drainage channel for sucking water and steam in the chamber and discharging it to the drainage tank;
Pressure measuring means for measuring the pressure in the chamber;
Control means for controlling the operation of the evacuating means based on the air pressure in the chamber measured by the air pressure measuring means;
With
The steam sterilizer is characterized in that the control means controls the evacuation means so as to start operation when a value of a change in air pressure in the chamber exceeds a threshold value.   The said control means controls the said vacuum drawing means to start an operation | movement when the absolute value of the ratio of the change of the pressure in the said chamber with respect to predetermined time falls below a predetermined value. Steam sterilizer.   The steam sterilizer according to claim 1, further comprising a cooling means between the chamber of the exhaust passage and the evacuation means. The evacuation means includes
A pump that draws fluid from one side and discharges fluid to the other;
An ejector having an inlet through which fluid discharged from the pump flows in, an outlet through which fluid flows out, and a suction port through which other fluid is sucked;
The steam sterilizer according to claim 1, comprising: The exhaust channel is
An outlet for draining fluid from the chamber;
An outlet for discharging fluid to the drainage tank;
An outlet for supplying water from the drainage tank;
A first flow path connecting the outlet and the suction port;
A second flow path connecting the outlet and the outlet;
A third flow path connecting the outlet and the inlet;
Have
The pump for sucking water from the water supply port side and flowing water to the inflow port side is provided between the outlet and the inflow port which are the third flow path. The steam sterilizer according to claim 4.

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