JPS6058975B2 - steam sterilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam sterilizer having a sterilization process for sterilizing objects to be sterilized such as injection needles and forceps with saturated steam and a drying process for drying them after sterilization. The inside of the chamber is maintained at a predetermined pressure, and during drying, the temperature is maintained at a predetermined temperature by a heat-sensitive element whose resistance value changes depending on the temperature via an electronic circuit.

When a steam sterilizer stores objects to be sterilized in a chamber and performs sterilization at saturated steam pressure, the pressure inside the chamber becomes extremely high, so the heater automatically opens and closes when the predetermined pressure is reached. The chamber is equipped with a pressure switch that maintains a predetermined pressure, and a thermostat connected in series with a heater to maintain the inside of the chamber at a predetermined temperature when drying is performed.

In the above configuration, during sterilization, chamber destruction is detected by the pressure applied to the chamber as a mechanical change, although temperature and pressure are proportional, so it is necessary to set a safe pressure value for the chamber destruction pressure value. Good in that it's accurate. However, during drying, the temperature inside the chamber is sensed through the air and the chamber by the thermostat installed in close contact with the outer wall of the chamber, so a heat lag occurs and opening and closing of the thermostat causes a large temperature difference within the chamber. This temperature difference caused fabrics such as gauze to burn in the high-temperature areas, and did not reach a temperature at which the drying ability could be fully demonstrated in the low-temperature areas. Furthermore, as mentioned above, the heater reaches a high temperature when the thermostat is closed, which shortens its lifespan and wastes more power than necessary.
The present invention has been made in view of the above-mentioned drawbacks, and will be explained below based on the drawings.

1 is a box-shaped frame, 2 is an oblong cylindrical chamber with an open front and a bottom at the rear, and 3 is a water storage tank installed on the side of the chamber, and a pipe 4 connects the inside of the chamber. Connected to the bottom.

Reference numeral 5 refers to a lid body that can open and close the opening of the chamber 2 from the inside to make it airtight; 6 refers to a sterilization heater whose sides are bent into a shape and is insulated and fixed to the inner bottom of the chamber; 7 refers to the outer periphery of the chamber 2; A band-shaped band wrapped tightly around the torso.
During the drying process, the drying heater cooperates with the sterilization heater 6 to dry the air in the chamber.

Reference numeral 8 denotes a water level detection rod having a pair of detection electrodes 9, 9'' on its upper part, the electrodes being positioned above the sterilization heater 6 and fixed to the inner bottom of the chamber 2;
'' is electrically connected to the chamber 2, and when the water injected from the tank 3 through the vibrator 4 reaches a predetermined water level located on the upper surface of the sterilization heater 6, the respective sensing electrodes 9, 9'' is short-circuited to operate a water level detection circuit, which will be described later, and water injection is completed.

Reference numeral 10 denotes a heat-sensitive element which is provided close to the sterilization heater 6 at the inner bottom of the chamber 2, and whose upper part is located approximately at the same position as the predetermined water level, and whose resistance value decreases with temperature.

Reference numeral 11 denotes a thermostat provided at the outer bottom of the chamber 2 and set at a temperature relatively higher than the normal temperature for preventing dry firing.

Next, the electric circuit will be explained. VC is a power supply circuit, TS
is a series circuit of the heat-sensitive element 10 and a resistor R1 for obtaining a comparison voltage, and two fixing resistors R2 for obtaining a reference voltage.
, R3, AP has one input terminal connected to the above-mentioned comparison voltage circuit side, the other input terminal connected to the above-mentioned reference voltage circuit side, and the output terminal connected to the other input terminal. Amplifier circuit VT with amplifier circuit
TC is a reference voltage circuit consisting of resistors R4 and R5 and a potential adjustment resistor VR; one input terminal of TC is connected to the connection between the resistor R5 of the reference voltage circuit T and the potential adjustment resistor VR; A temperature control circuit VS for the drying heater 7, which mainly has a comparator CPl, whose input terminal is connected to the output terminal of the amplifier AF of the amplifier circuit 1, has one input terminal connected to the temperature control circuit TC. is connected to the other input terminal of the comparator CPl, and the other input terminal is connected to the resistor R of the reference voltage circuit ■T.
4 and a resistor R5, which mainly has a comparator CP2, and switches the emitter temperature during sterilization and drying according to each process. VA is a potential setting device consisting of a transistor TRl connected in parallel to the potential adjustment resistor (R) of the reference voltage circuit (T), and RS is the other input terminal of the temperature control circuit (TC) and the potential comparison circuit (VS).
Four normally open reset switches are connected between the connection part with one input terminal of the LT and the chassis side, and the base is connected to the drive transistor TR2 whose base is connected to the output terminal of the potential comparator circuit ■S with the LT beam emitter circuit and the base. is connected to the collector of the transistor, the collector is connected to a power source, and the emitter is connected to a drive circuit D consisting of a heater control relay for controlling sterilization and drying heaters 6 and 7, which will be described later. The drive circuit will be described. T is a timer motor TM, a first timer switch TSL for executing the sterilization and drying process which is turned on for a certain period of time by the motor, and the first timer switch 0FF.
The timer device is composed of a second timer switch 'TS2 for notification which is turned ON for about 3 to 2 hours, and the first timer switch TS1 is connected to the emitter of the cutoff transistor TR3. X1 is the cutoff transistor T
The first relay is connected between the connection part of R3 and the first timer switch TSL and the chassis, and the normally open relay contact Xl
It has S. RYl is a drying heater control relay whose base is connected to a drive transistor TR4 whose base is connected to the output terminal of the temperature control circuit TC, and has a normally open relay contact RSl. X2 is a second relay connected in parallel to the series circuit of the drying heater control relay RYl and the drive transistor TR4, and has a relay contact X2S.
It has a movable contact X2a, a fixed contact X2b connected to the drying heater control relay RYl, and a normally closed fixed contact X2C of the movable contact X2a. STl is the first timer switch TSL and the second timer switch TS
A drying start switch ST2 connected between the connection part of No. 2 and the drying heater control relay RYl is a sterilization start switch connected in series to the normally closed fixed contact X2C of the second relay X2, and X3 is connected in series to the switch. The third relay connected has a self-holding relay contact X3S connected in parallel to the sterilization start switch ST2, a movable contact X,
0S having a and two fixed contacts X3b and X3C is an oscillation circuit consisting of a multivibrator connected to the second timer switch TS2, and a buzzer relay BX is connected to its output transistor TR5, The alarm is intermittent for about 3 hours when the second timer switch TS2 is ON before the end of sterilization. X4 is a fourth relay with one end connected to a relay contact of a fifth relay described later and the other end connected to a drive transistor TR6, and has a relay contact X4S and a movable contact X4.
a and two fixed contacts X4b and X4C, the movable contact X4a is connected to the sterilization start switch ST2, one normally closed fixed contact X4C of the movable contact X4a is connected to the water level detection circuit side, and the other fixed contact The contact X4b is connected to the sixth relay for driving the timer motor TM and the pressure switch side. WS is a water level detection circuit having one end connected to the fixed contact X4C and having a water level detection electrode 9,9'' on one side;
X5 is a fifth relay which has one end connected to the fixed contact X4C of the fourth relay X4 and the other end connected to the output transistor TR7 of the water level detection circuit WS, and has a movable contact X5a and two fixed contacts X5b and X5C, and has a predetermined contact. When the water level is detected, the other normally closed relay contact X5S is opened and the 4th relay
Neutralize 4. PSl is a first pressure switch having a movable contact PSa and two fixed contacts PSb and PSc, and when the inside of the chamber 2 reaches a predetermined pressure, the movable contact PSa switches from one fixed contact PSc to the other fixed contact PSb. It is something. RY2 is a sterilization heater control relay connected to one fixed contact PSc of the first pressure switch PSl, and a movable contact PSa of the first pressure switch PSl.
The sterilization heater 6 is turned off by the operation. X6 is a sixth relay for driving the timer motor TM connected in series with the drying start switch STl, and has two relay contacts X6l and X62. It is connected between fixed contact X46 of X4. TR8 is a transistor for generating a continuous sound of a buzzer, which is connected in parallel to the output transistor TR5 of the oscillation circuit OS and whose base is connected to the drying start switch STl. M is a main circuit that operates each electrical component based on the operation of the relay contacts driven by the respective relays of the drive circuit D described above.

The specific circuit will be explained. AC is an alternating current power source, and the sterilization heater 6 is connected in series with a relay contact RS2 of a sterilization heater control relay RY2, and is connected to the alternating current power source AC via a thermostat 11. PLl is a sterilization indicator lamp, and the relay contact XlS of the first relay X1 and the fourth relay X4
The sterilization heater 6 is connected to the relay contact X4S and connected in parallel to the sterilization heater 6. The drying heater 7 is connected in series to the relay contact RSl of the drying heater control relay RYl, and this series circuit is connected to the relay contact R of the sterilization heater 6.
Connected in parallel to S2. PL2 is a power indicator lamp connected to the relay contact XlS of the first relay X1 via the thermostat 11, pressure is a buzzer connected in series to the relay contact BXS of the buzzer relay BX, and PL3 is the relay contact X2S of the second relay X2. BV is an electromagnetic valve for injecting water into the chamber 2 provided in a part of the vibrator 4, and AS is an exhaust switch that is closed in conjunction with the drying start switch STl. It is connected between the display lamp PL3, the connection part of the relay contact X2S of the second relay X2, and the electromagnetic valve B2, and after sterilization is completed, the electromagnetic valve BV is driven to exhaust the pressure inside the chamber 2. PL4 is a water injection indicator lamp connected in series to the fixed contact X3b of the third relay X5, and this series circuit is connected in parallel to the electromagnetic valve BV. P
S2 is a second pressure switch fixed to the chamber 2, which closes at a predetermined pressure lower than the first pressure switch PSl, and is connected to the normally closed side fixed contact X3 of the third relay X3.
C and the normally closed fixed contact X5C of the fifth relay X5. The timer motor TM is connected in series to the relay contact X6l of the sixth relay X6. Next, regarding the operation, the basic principle of operation is carried out in the order of steps as shown in FIG. First, the sterilization process will be explained. After opening the lid 5, storing objects to be sterilized such as syringe needles and forceps, and closing the lid, when AC power is supplied, the cutoff transistor TR3 in the limiter circuit LT is 0N, so the drive circuit D
operates, the first relay X1 operates, and its relay contact XlS becomes ON. Then, the sterilization operation time is set by the timer device T according to the object to be sterilized, the first timer switch TSL is set to 0N, and the sterilization start switch ST2 is set to 0N.
When set to N, the third relay X3 is driven, and the saw contact X3S connected in parallel to the sterilization start switch ST2 turns ON and self-holds, and the movable contact X3a of the third relay X3 is connected to one fixed contact X3b. Also, the water level detection circuit W is connected via the movable contact X4a and the fixed contact X4C of the fourth relay X4.
The fifth relay X5 driven by the output of S via the output transistor TR7 opens its relay contact X5S and connects its movable contact X5a to one fixed contact X5b.
The electromagnetic valve BV is opened, water in the water storage tank 3 is injected into the chamber 2 via the vibrator 4, and the water injection status is displayed on the water injection display lamp PL4. Eventually, when water is poured into the bottom of the chamber 2 to a predetermined water level, the respective detection electrodes 9, 9'' are short-circuited through the water, and the output of the water level detection circuit WS is caused by the output transistor TR7 turning 0FF and the fifth relay X5.
While setting the relay contact X5S to 0N, the fourth relay X4
to drive the movable contact X4a to the other fixed contact
4b and the movable contact PSa of the first pressure switch PSl
The sterilization heater control relay RY2 is driven through one fixed contact PSC, and the relay contact RS2 of the relay is set to 0.
Turn the temperature to N and energize the sterilization heater 6 to heat the water in the chamber 2, then turn the first pressure filter FPSL 0N to OFF.
Controlled by This 0N operation of the first pressure switch PSl controls the sixth relay X6 and sets the relay contact X6l to 0N.
N and then drives the timer motor TM to perform a subtraction operation for the sterilization operation time. Electricity is supplied in conjunction with the self-holding of 32, and the object to be sterilized is sterilized with saturated steam. At this time, as the relay contact X4S of the fourth relay X4 turns ON, the sterilization indicator lamp PLl lights up to indicate that sterilization is in progress. Then, after the aforementioned predetermined water level is detected, the relay contact X5 is deenergized by the fifth relay X5.
S(7) Due to 0N operation, the transistor TRl of the potential setting device ■A becomes 0N, so the potential adjustment resistor ■R is short-circuited, and the reference potential of the other input terminal of the comparator CP2 of the potential comparison circuit VS is low. Become. Therefore, the difference between the output potential of the amplifier and the output potential due to a change in the resistance value of the heat-sensitive element 10 during the sterilization process becomes small, and the limiter temperature becomes low. That is, in the case of abnormal overheating in which the sterilization heater 6 is continuously energized for some reason, the resistance value of the heat-sensitive element 10 rapidly decreases, and the output level of the amplifier rises, increasing the potential comparator circuit V.
The output of the comparator CP2 of S changes from "L" to "H", the drive transistor TR2 is turned ON, the cutoff transistor TR2 is turned OFF, the mitter circuit LT is cut off, and the power to the sterilization heater 6 is cut off. Eventually, when the timer motor TM reaches about 3' before stopping, the second timer switch TS2 turns 0N and the oscillation circuit 0S turns the output transistor TR5 0N-OFF intermittently, causing the buzzer relay BX to operate intermittently. BZ is played intermittently.

Thereafter, the timer device T stops and the sterilization process is completed, and the second pressure switch PS2 is set to ON.
The movable contact X5a of the fifth relay X5 and the other fixed contact X
, the electromagnetic valve B is opened via the other fixed contact X3C and the movable contact X3a of the third Cl relay Becomes lucky. The drying process will now be explained. With the aforementioned lid body 5 half-open and the inside of the chamber 2 communicating with the outside air, the drying time is set by the timer device T and the first time switch TSL is set to 0N.
When the drying start switch STl is set to 0N, the second
Relay X2 is driven and its movable contact X2a becomes fixed contact X
2b and enters the self-holding state, and the relay contact
2S becomes 0N and the drying indicator lamp PL3 lights up. On the other hand, as the sixth relay X6 is driven, relay contact X6l becomes 0.
N, the timer motor TM performs a timing operation, and the fourth relay side and water level detection circuit side are in a power-off state, so the transistor TRl of the potential setting device VA becomes 0.
The other input terminal of the comparator 0P2 of the potential comparison circuit ■S, which becomes an FF, is connected to the resistor R4, the resistor R5, and the potential adjustment resistor ■R, so that the reference potential becomes high. Therefore, the amplifier AF due to the resistance value change of the heat sensitive element 10 during the drying process.
The limiter temperature that has a large difference between the output potential and the output potential becomes high. To dry the object to be sterilized, the output of the amplifier circuit AP drives the drive transistor TR4 via the comparator CPl of the temperature control circuit TC to drive the drying heater control relay RYl, and sets the relay contact RSl to 0N. and drying heater 7 are connected in series to form sterilization heater 6.
The inside of the chamber 2 is heated in cooperation with the Hereafter, heat-sensitive element 1
Based on the resistance value change of 0, the amplifier circuit Oki and temperature control circuit T
The temperature is maintained at a predetermined temperature via C. In the case of abnormal heating, the limiter circuit LT is cut off by the output of the potential comparator circuit ①S, as in the case of the sterilization process described above. Eventually, when approximately 30 seconds have elapsed before the timer motor TM stops, the second timer switch TS2 turns ON, turns the transistor TR8 ON, and causes the buzzer K to sound continuously. Thereafter, the timer device T is stopped and the drying process is completed. As described above, the present invention includes a chamber for storing objects to be sterilized, a heater installed in the chamber and generating saturated steam in the chamber,
a pressure switch that turns off the power to the heater to maintain a predetermined pressure in the chamber and starts subtracting the sterilization operation time; and a pressure switch that is provided close to the heater and controls the heater via a temperature detection circuit that controls the temperature of the chamber. It is equipped with a heat-sensitive element whose resistance value changes depending on the temperature to maintain the chamber at a predetermined temperature, so during the sterilization process, the pressure switch is used to accurately set the safe pressure value to maintain the chamber at a predetermined pressure. In addition, this pressure switch serves as a so-called start switch for starting subtraction of the sterilization operation time, and the sterilization time is counted after reaching a predetermined pressure value, so that accurate sterilization operation can be performed. In addition, during the drying process, a heat-sensitive element whose resistance value changes depending on the temperature is placed close to the heater and is maintained at a predetermined temperature via an electronic circuit, eliminating the need for temperature differences like with a thermostat and preventing gauze, etc. due to high temperatures. It can prevent burning and decrease in drying ability due to low temperature. Further, since the heat-sensitive element relatively accurately senses the radiant heat of the heater, the heater does not generate more heat than necessary, and its lifespan can be extended.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of the steam sterilizer of the present invention, Fig. 2 is an internal explanatory view, Fig. 3 is an overall circuit diagram, and Fig. 4 is a main part circuit diagram.
FIG. 5 shows a process diagram. 2... Chamber, 6, 7... Sterilization heater and drying heater, 10... Heat sensitive element, TS... Temperature detection circuit, AF... Amplifier, TC... Temperature control circuit,
PSL...First pressure switch.

Claims (1)

[Claims] 1. A chamber for storing objects to be sterilized, a heater installed in the chamber to generate saturated steam in the chamber, and a sterilization operation time of Steam comprising a pressure switch that starts subtraction, and a heat-sensitive element that is provided close to the heater and whose resistance value changes depending on the temperature to control the heater via a temperature detection circuit and maintain the chamber at a predetermined temperature. Sterilizer.