JP4469477B2 - Steam sterilization apparatus and steam sterilization method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a steam sterilization apparatus and a steam sterilization method, and more specifically, is provided in a sterilization chamber of a main body as a pressure vessel, and heats water stored in the storage unit and water stored in the storage unit, A steam sterilizer comprising heating means for generating water vapor in the sterilization chamber and a stopper valve provided in a steam extraction pipe for discharging the generated water vapor outside the sterilization chamber, and the steam sterilization device inserted into the sterilization chamber of the steam sterilization device The present invention relates to a steam sterilization method for subjecting an object to be sterilized to steam sterilization.
[0002]
[Prior art]
  As the steam sterilization apparatus, a steam sterilization apparatus shown in FIG. 8 is widely used as a small and simple steam sterilization apparatus. A main body 102 as a pressure container of the steam sterilization apparatus 100 shown in FIG. 8 is provided with a sterilization chamber 112 that can be hermetically sealed by a lid 104, and an object to be sterilized is placed in the sterilization chamber 112. A mounting plate 110 is provided.
  Further, a recess for storing water is formed as a water storage section 116 below the mounting plate 110, and a heater 118 for heating the stored water and generating water vapor is disposed in the water storage section 116. Yes. The water storage unit 116 is supplied with water from a water supply tank 126 to which makeup water is supplied through a pipe 127 via a water supply pipe 128 provided with a control valve 130 on the way.
  The main body 102 is provided with a pressure sensor P and a temperature sensor T that detect the internal pressure and temperature of the sterilization chamber 112, and a stored water detection sensor FL that detects the presence or absence of stored water in the water storage unit 116. .
  Further, a steam extraction pipe 119 for extracting water vapor from the sterilization chamber 112 of the main body 102 and a water extraction pipe 122 for extracting water from the water storage section 116 are provided. The steam extraction pipe 119 is provided with a control valve 120 as a stopper valve, and the water extraction pipe 122 is provided with a motor-driven control valve 124.
  Further, air purified by a filter or the like is supplied to the sterilization chamber 112 through an air supply pipe 132 provided with a motor-driven control valve 134 and a heater 136 in the middle.
[0003]
  FIG. 9 shows changes in the temperature and pressure of the sterilization chamber 112 when the object to be sterilized contained in the sterilization chamber 112 of the steam sterilization apparatus 100 shown in FIG. 8 is subjected to steam sterilization. First, with the control valve 124 of the drain pipe 122 opened, the control valve 134 of the air supply pipe 132 is opened, hot air heated by the heater 136 is supplied into the sterilization chamber 112, and the sterilization chamber 112 and the object to be sterilized are supplied. Preheat for a predetermined time.
  Further, the control valve 130 is opened, and water is supplied from the water supply tank 126 to the water storage unit 116 via the water supply pipe 128. This water supply is performed until the stored water detection sensor FL detects it.
  In this way, the stored water stored in the water storage unit 116 is heated by the heater 118 to generate water vapor, and the generated water vapor is extracted from the steam extraction pipe 119 together with the air in the sterilization chamber 112, whereby the sterilization chamber 112. The air inside is replaced with water vapor.
  Here, as shown in FIG. 9A, when the temperature in the sterilization chamber 112 is flat at a constant temperature, that is, when the temperature of the sterilization chamber 112 has reached the boiling point of the stored water, the inside of the sterilization chamber 112 is water vapor. The control valve 120 of the steam extraction pipe 119 is closed, and the inside of the sterilization chamber 112 is set to the sterilization temperature / pressure. When the sterilization chamber 112 reaches the sterilization temperature / pressure, this state is maintained for a predetermined time to sterilize the article to be sterilized.
  Next, when steam sterilization of the object to be sterilized is completed, the control valve 124 of the drain pipe 122 is opened, and water vapor and heated water in the sterilization chamber 112 are extracted.
  Thereafter, the air purified by a filter or the like was blown as hot air into the sterilization chamber 112 via the air supply pipe 132 provided with a motor-driven control valve 134 and a heater 136 on the way, and steam sterilization was performed. The object to be sterilized is dried to complete a series of sterilization processes.
[0004]
[Problems to be solved by the invention]
  The steam sterilization apparatus 100 shown in FIG. 8 can perform steam sterilization with a relatively simple structure.
  However, in the steam sterilization apparatus 100 shown in FIG. 8, there is no means for confirming that the steam replacement in the sterilization chamber 112 is sufficient, and the steam evacuation is performed with air remaining in the sterilization chamber 112. There is a case where the control valve 120 of the outlet pipe 119 is closed and the inside of the sterilization chamber 112 is heated and pressurized. In this case, even if the pressure in the sterilization chamber 112 reaches the sterilization pressure, the temperature in the sterilization chamber 112 does not reach the sterilization temperature, and sterilization failure occurs. Such poor sterilization tends to occur when steam sterilization is performed on an object to be sterilized such as linen which is difficult to discharge air.
  On the other hand, by continuing the state A shown in FIG. 9 for a long time, the inside of the sterilization chamber 112 can be sufficiently replaced with steam, but the sterilization processing time becomes longer.
  Accordingly, an object of the present invention is to provide a steam sterilization apparatus and a steam sterilization method capable of confirming that the steam replacement in the sterilization chamber is sufficiently performed in a short time and easily, and that can surely set the sterilization chamber at a predetermined sterilization temperature and pressure. Is to provide.
[0005]
[Means for Solving the Problems]
  As a result of repeated studies to solve the above problems, the present inventor, when the sterilization chamber is sufficiently replaced with water vapor, when the pressure increasing operation for increasing the pressure in the sterilization chamber and the pressure decreasing operation for decreasing the pressure are repeated alternately, In each operation, when the pressure in the sterilization chamber becomes the same pressure, the temperature in the sterilization chamber exhibits substantially the same temperature, and the temperature is substantially the same as the saturated water vapor temperature corresponding to the pressure in the sterilization chamber. The temperature was found and the present invention was reached.
[0006]
  That is, the present invention is provided in a sterilization chamber of a main body part as a pressure vessel, and a storage unit that stores water, and heating means that heats water stored in the storage unit and generates water vapor in the sterilization chamber. In a steam sterilization apparatus comprising a stopper valve provided in a steam extraction pipe for discharging generated steam to the outside of the sterilization chamber,A pressure sensor for detecting the internal pressure of the sterilization chamber, a temperature sensor for detecting the temperature of the sterilization chamber, a memory in which an upper limit pressure and a lower limit pressure are stored in advance,Pressurization operation that closes the stopper valve and raises and raises the pressure of the sterilization chamber with water vapor generated by heating by the heating meansCompare the measured pressure measured by the pressure sensor with the upper limit pressure stored in the memory, and continue until the measured pressure matches the upper limit pressure. A step of storing the temperature measured by the temperature sensor in the memory as a measured high pressure side temperature, and then a pressure reducing operation for opening the stopper valve and discharging the water vapor in the sterilization chamber together with the air, a measured pressure measured by the pressure sensor, Compare the lower limit pressure stored in the memory and continue until the measured pressure matches the lower limit pressure, and when the measured pressure matches the lower limit pressure, measure the temperature measured by the temperature sensor at this time Storing the temperature as a temperature in a memory; continuing the step-up operation; storing the measured high-pressure side temperature in a memory; and continuing the step-down operation. Steps and the measured low pressure side temperature repeated at least twice and storing in the memory, the temperature difference ΔT between the previous measurement the high-pressure side temperature and the current measured pressure side temperature of _H And the temperature difference ΔT between the previous measured low pressure side temperature and the current measured low pressure side temperature. _L , A value α previously stored in the memory and a temperature difference ΔT _H And a value β stored in the memory in advance and a temperature difference ΔT _L And ΔT _H ≦ α and ΔT _L If the relationship of ≦ β is not satisfied, the process returns to the step of repeating the step-up operation and the step-down operation again, and ΔT _H ≦ α and ΔT _L If the relationship of ≦ β is satisfied, the temperature difference ΔT between the measured high-pressure side temperature this time and the saturated water vapor temperature when the upper limit pressure stored in the memory in advance is reached _HB And the temperature difference ΔT between the measured low pressure side temperature and the saturated water vapor temperature when the lower limit pressure stored in advance in the memory is reached _LB And a value γ previously stored in the memory and a temperature difference ΔT _HB And a value δ stored in the memory in advance and a temperature difference ΔT _LB And ΔT _HB ≦ γ and ΔT _LB If the relationship of ≦ δ is not satisfied, the process returns to the step of repeating the step-up operation and the step-down operation again, and ΔT _HB ≦ γ and ΔT _LB If the relationship of ≦ δ is satisfied, it is determined that the sterilization chamber has been sufficiently replaced with water vapor, the stopper valve is closed, and the sterilization chamber is pressurized with saturated water vapor to the desired sterilization pressure to sterilize temperature / pressure. And execute the stepsA steam sterilizer is provided with a control unit.
[0007]
  Further, the present invention is provided in a sterilization chamber of a main body portion as a pressure vessel, and a storage unit that stores water, and heating means that heats water stored in the storage unit and generates water vapor in the sterilization chamber. A stopper valve provided in a steam extraction pipe for discharging the generated water vapor to the outside of the sterilization chamber;A pressure sensor for detecting the internal pressure of the sterilization chamber, a temperature sensor for detecting the temperature of the sterilization chamber, a memory in which an upper limit pressure and a lower limit pressure are stored in advance.When steam sterilization is performed on an object to be sterilized inserted into the sterilization chamber using the steam sterilization apparatus provided,SaidPressurization operation that closes the stopper valve and raises and raises the pressure of the sterilization chamber with water vapor generated by heating by the heating meansCompare the measured pressure measured by the pressure sensor with the upper limit pressure stored in the memory, and continue until the measured pressure matches the upper limit pressure. A step of storing the temperature measured by the temperature sensor in the memory as a measured high pressure side temperature, and then a pressure reducing operation for opening the stopper valve and discharging the water vapor in the sterilization chamber together with the air, a measured pressure measured by the pressure sensor, Compare the lower limit pressure stored in the memory and continue until the measured pressure matches the lower limit pressure, and when the measured pressure matches the lower limit pressure, measure the temperature measured by the temperature sensor at this time Storing the temperature as a temperature in a memory; continuing the step-up operation; storing the measured high-pressure side temperature in a memory; and continuing the step-down operation. Steps and the measured low pressure side temperature repeated at least twice and storing in the memory, the temperature difference ΔT between the previous measurement the high-pressure side temperature and the current measured pressure side temperature of _H And the temperature difference ΔT between the previous measured low pressure side temperature and the current measured low pressure side temperature. _L , A value α previously stored in the memory and a temperature difference ΔT _H And a value β stored in the memory in advance and a temperature difference ΔT _L And ΔT _H ≦ α and ΔT _L If the relationship of ≦ β is not satisfied, the process returns to the step of repeating the step-up operation and the step-down operation again, and ΔT _H ≦ α and ΔT _L If the relationship of ≦ β is satisfied, the temperature difference ΔT between the measured high-pressure side temperature this time and the saturated water vapor temperature when the upper limit pressure stored in the memory in advance is reached _HB And the temperature difference ΔT between the measured low pressure side temperature and the saturated water vapor temperature when the lower limit pressure stored in advance in the memory is reached _LB And a value γ previously stored in the memory and a temperature difference ΔT _HB And a value δ stored in the memory in advance and a temperature difference ΔT _LB And ΔT _HB ≦ γ and ΔT _LB If the relationship of ≦ δ is not satisfied, the process returns to the step of repeating the step-up operation and the step-down operation again, and ΔT _HB ≦ γ and ΔT _LB If the relationship of ≦ δ is satisfied, it is determined that the sterilization chamber has been sufficiently replaced with water vapor, the stopper valve is closed, and the sterilization chamber is pressurized with saturated water vapor to the desired sterilization pressure to sterilize temperature / pressure. And including the stepIt is also a featured steam sterilization method.
[0008]
  In this invention, the upper limit pressure and the lower limit pressure of the sterilization chamber are lower than the sterilization pressure for sterilizing the article to be sterilized inserted in the sterilization chamber and higher than the atmospheric pressure, thereby discharging the amount of water vapor. Can be reduced.
  Furthermore, by setting the differential pressure between the upper limit pressure and the lower limit pressure to 0.02 MPa, the pressure difference and temperature difference in the sterilization chamber exceeding the error range of the pressure sensor and the temperature sensor can be obtained.
[0009]
  According to the present invention, by alternately repeating the pressure increasing operation for increasing the pressure in the sterilization chamber and the pressure decreasing operation for decreasing the pressure, whether or not the sterilization chamber is sufficiently replaced with water vapor while replacing the sterilization chamber with water vapor. You can check in a short time.
  For this reason, if air remains in the sterilization chamber, the pressure increase and decrease operations of the sterilization chamber are repeated, and after the residual air is removed and the sterilization chamber is sufficiently steam-substituted, the temperature and pressure of the sterilization chamber are increased. The sterilization temperature and pressure can be adjusted to proceed to the sterilization process.
  Therefore, although the sterilization process has proceeded, even if the pressure in the sterilization chamber reaches the sterilization pressure due to the air remaining in the sterilization chamber, the temperature in the sterilization chamber becomes lower than the sterilization temperature. It is possible to effectively prevent a sterilized product from becoming sterilized poorly.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  An example of a steam sterilization apparatus according to the present invention is shown in FIG. A main body 12 of the steam sterilization apparatus 10 shown in FIG. 1 is provided with a sterilization chamber 16 that can be hermetically sealed by a lid 14, and a mounting plate on which an object to be sterilized is placed. 18 is provided.
  Further, a recess for storing water is formed as a water storage section 20 below the mounting plate 18, and a heater 22 for heating the stored water and generating water vapor is disposed in the water storage section 20. Yes. The water storage unit 20 is supplied with water from a water supply tank 26 to which makeup water is supplied by a pipe 24 via a water supply pipe 28 provided with a control valve 27 on the way.
  The main body 12 is provided with a pressure sensor P and a temperature sensor T that detect the internal pressure and temperature of the sterilization chamber 16, and a stored water detection sensor FL that detects the presence or absence of stored water in the water storage unit 20. .
  A steam extraction pipe 30 for extracting water vapor from the sterilization chamber 16 of the main body 12 and a water extraction pipe 34 for extracting water from the water storage section 20 are provided. The steam extraction pipe 30 is provided with a control valve 32 as a stopper valve, and the water extraction pipe 34 is provided with a motor-driven control valve 36.
  Furthermore, the air purified by a filter or the like is supplied to the main body 16 via an air supply pipe 42 provided with a motor-driven control valve 38 and a heater 40 in the middle.
  The control valves 27, 32, 36, and 38 provided in each of these pipes are controlled by a control unit 50 provided on the panel plate. As shown in FIG. 2, the control unit 50 includes a CPU 52, a memory 54, a display unit 56 such as a liquid crystal display, and an input unit 58 such as a numeric keypad, and measures from a pressure sensor P and a temperature sensor T provided in the main body unit 12. Pressure (P_M) And measured temperature (T_M) To control each control valve based on the signal.
[0011]
  When steam sterilizing an object to be sterilized contained in the sterilization chamber 16 of the steam sterilization apparatus 10 shown in FIG. 1, first, the control of the air supply pipe 42 is performed with the control valve 36 of the drain pipe 34 opened. The valve 38 is opened, hot air heated by the heater 40 is supplied into the sterilization chamber 16, and the sterilization chamber 16 and an object to be sterilized are preheated for a predetermined time.
  Furthermore, the control valve 27 is opened, and water is supplied from the water supply tank 26 to the water storage unit 20 via the water supply pipe 28. This water supply is performed until the stored water detection sensor FL detects it.
  In this manner, the stored water stored in the water storage unit 20 is heated by the heater 22 to generate water vapor, and the generated water vapor is extracted from the vapor extraction pipe 30 together with the air in the sterilization chamber 16, thereby sterilization chamber 16. The air inside is replaced with water vapor.
  At the time of this steam replacement, the control valve 32 is controlled by the control unit 50 according to the procedure shown in FIG. The procedure shown in FIG. 3 starts when the heater 22 starts heating the water stored in the water storage unit 20.
  First, the integer n stored in the memory 54 is changed to step S.₁Set to 0 and then step S₂1 is added and stored in the memory 54, and then the control valve 32, which is a stop valve, is closed, and the pressure increase in the sterilization chamber 16 is started (step S)._Three).
[0012]
  Measured pressure P measured by pressure sensor P after starting sterilization chamber 16 pressure increase_MAnd the set high pressure P as the upper limit pressure stored in advance in the memory 54_H(Step S_Four), P_M≠ P_HStep if_ThreeReturning to step S2, the pressurization operation of the sterilization chamber 16 is continued.
  On the other hand, P_M= P_HThe measured temperature T measured by the temperature sensor T in the sterilization chamber 16_MMeasure high pressure side temperature T_Hn(Step S)_Five).
  Next, the control valve 32 is opened and pressure reduction in the sterilization chamber 16 is started (step S).₆). Measured pressure P measured by pressure sensor P after starting sterilization chamber 16 pressure reduction_MAnd the set low pressure P as the lower limit pressure stored in advance in the memory 54_L(Step S₇), P_M≠ P_LStep if₆Returning to step S2, the pressure reduction operation of the sterilization chamber 16 is continued.
  On the other hand, P_M= P_LThe measured temperature T measured by the temperature sensor T in the sterilization chamber 16_MMeasure low pressure side temperature T_Ln(Step S)₈).
  Since it is necessary to repeat such step-up operation and step-down operation at least twice, the step₉To determine whether or not the value of n stored in the memory 54 is 2 or more, and if the value of n is 1,₂Returning to step 1, the step-up operation and the step-down operation are repeated once more.
  Here, the set high-pressure side pressure P_HAnd set low pressure P_LThe amount of water vapor discharged can be reduced by setting the pressure to be lower than the sterilization pressure for sterilizing the article to be sterilized inserted into the sterilization chamber 16 and higher than the atmospheric pressure.
  Further, by setting the differential pressure between the upper limit pressure and the lower limit pressure to 0.02 MPa, the pressure difference and temperature difference in the sterilization chamber exceeding the error range of the pressure sensor and the temperature sensor can be obtained.
[0013]
  Meanwhile, step₉When the value of n is 2 or more, the step-up operation and the step-down operation are repeated twice or more. For this reason, during the n-th pressure increase operation, the upper limit pressure (set high pressure side pressure P_H) Of the sterilization chamber 16 that has reached (measured high-pressure side temperature T)_Hn) And (n-1) previous temperature in the pressure increasing operation (measured high pressure side temperature T)_{H (n-1)}) Temperature difference from_HAnd the lower limit pressure (set low pressure P_L) Of the sterilization chamber 16 that has reached (the measured low-pressure side temperature T)_Ln) And (n-1) previous temperature in the step-down operation (measured low-pressure side temperature T)_{L (n-1)}) Temperature difference from_LAnd calculate (step_Ten).
  This temperature difference ΔT_H, ΔT_LAre compared with the values α and β stored in the memory 54 in advance (step S).₁₁).
  Where ΔT_HAnd ΔT_LIs one of ΔT_H≦ α, ΔT_LIf the relationship ≦ β is not satisfied, step S₂Returning to step 3, the step-up operation and the step-down operation are repeated again.
  On the other hand, ΔT_HAnd ΔT_LAre both ΔT_H≦ α, ΔT_L≦ β satisfies the relationship, that is, the current temperature (measured high-pressure side temperature T_Hn) And (n-1) previous temperature in the pressure increasing operation (measured high pressure side temperature T)_{H (n-1)}) And substantially the same temperature (measured low pressure side temperature T) in the nth step-down operation._Ln) And (n-1) previous temperature in the step-down operation (measured low-pressure side temperature T)_{L (n-1)}) Is substantially equal to step S₁₂Proceed to
  The values of α and β are preferably set to about 3 ° C. in consideration of measurement errors of the temperature sensor T and the pressure sensor P.
[0014]
  Step S₁₂Then, in the n-th pressurization operation, the sterilization chamber 16 is set to the upper limit pressure (set high-pressure side pressure P_H) Current temperature (measured high pressure side temperature T)_Hn) And the saturated water vapor temperature (T_HB) Temperature difference from_HBIn the n-th pressure reduction operation, the sterilization chamber 16 has a lower limit pressure (set low pressure P_L) Current temperature (measured low pressure side temperature T)_Ln) And the saturated water vapor temperature (T_LB) Temperature difference from_LBAnd calculate.
  Step S₁₂Temperature difference ΔT calculated by_HBAnd temperature difference ΔT_LBAre also compared with the values γ and δ previously stored in the memory 54 (step S).₁₃).
  Where ΔT_HBAnd ΔT_LBIs one of ΔT_HB≦ γ, ΔT_LBIf the relationship ≦ δ is not satisfied, step S₂Returning to step 3, the step-up operation and the step-down operation are repeated again.
[0015]
  On the other hand, ΔT_HBAnd ΔT_LBAre both ΔT_HB≦ γ, ΔT_LBIf the relationship ≦ δ is satisfied, that is, the current temperature (measured high-pressure side temperature T_Hn) And T_HnSaturated water vapor temperature (T_HB) And substantially the same temperature (measured low pressure side temperature T) in the nth step-down operation._Ln) And T_LnSaturated water vapor temperature (T_LB) Is substantially equal, it can be determined that the interior of the sterilization chamber 16 has been sufficiently replaced with water vapor, and the control valve 32 is closed (step S).₁₄3) and the pressure in the sterilization chamber 16 is increased to a sterilization temperature / pressure.
  When the sterilization chamber 16 reaches the sterilization temperature / pressure, this state is maintained for a predetermined time to sterilize the article to be sterilized.
  Next, when the sterilization of the article to be sterilized is completed, the control valve 36 of the drain pipe 34 is opened, and the water vapor and the heated water in the sterilization chamber 16 are extracted.
  Thereafter, the air purified by a filter or the like is supplied into the sterilization chamber 16 via an air supply pipe 42 provided with a motor-driven control valve 38 and a heater 40 in the middle, and subjected to steam sterilization. The sterilized product is dried to complete a series of sterilization processes.
  Note that the values of γ and δ are preferably set to about 3 ° C. in consideration of measurement errors of the temperature sensor T and the pressure sensor P.
[0016]
  FIG. 4 shows changes in temperature and pressure of the sterilization chamber 16 controlled by the procedure shown in FIG. In FIG. 4, when a predetermined amount of stored water is stored in the water storage unit 20 preheated by the heater 22, the control in the procedure shown in FIG. 3 is started.
  Here, an upper limit pressure (set high pressure side pressure P_H) 0.03 MPa [corresponding saturated water vapor temperature (T_HB); 107.03 ° C.], the lower limit pressure in the pressure reduction operation (set low pressure P_L) 0.01 MPa [corresponding saturated water vapor temperature (T_LB); 102.32 ° C.]. The values of α, β, γ, and δ were 3 ° C., respectively.
  Under such setting conditions, as shown in FIG. 4, the interior of the sterilization chamber 16 could be replaced with water vapor by repeating each of the pressure increasing operation and the pressure decreasing operation in the sterilization chamber 16 seven times.
  That is, the current temperature (measured high-pressure side temperature T in the seventh step-up operation)_H7) Is the previous temperature (measured high-pressure side temperature T) in the sixth step-up operation._H6) And T_H7Saturated water vapor temperature (T_HB) And the current temperature (measured low-pressure side temperature T) in the seventh step-down operation._L7) Is the previous temperature (measured low-pressure side temperature T) in the sixth step-down operation._L6) And T_L7Saturated water vapor temperature (T_LB) Is substantially the same temperature.
  As described above, in the pressure increasing operation and the pressure decreasing operation in the sixth time and the seventh time, the pressure / temperature of the sterilization chamber 16 exhibits substantially the same temperature change according to the pressure change in each operation, and the seventh time. In the pressure increase operation and the pressure decrease operation, the temperatures at the upper limit pressure and the lower limit pressure are substantially equal to the saturated steam temperature corresponding to each of the upper limit pressure and the lower limit pressure, so that the sterilization chamber 16 was sufficiently replaced with steam. It can be judged.
[0017]
  In the steam sterilization apparatus shown in FIG. 1, since the interior of the sterilization chamber 16 is always at atmospheric pressure or higher, the steam replacement time in the sterilization chamber 16 and the drying time in the drying process tend to be long. In order to shorten the steam replacement time in the sterilization chamber 16 and the drying time in the drying process, a steam sterilization apparatus 60 provided with a vacuum pump 62 can be suitably used as shown in FIG.
  In the steam sterilization apparatus 60 shown in FIG. 5, one end is a vacuum pump between the control valve 32, which is a stopper valve provided in the steam extraction pipe 30 that extracts steam from the sterilization chamber 16 of the main body 12, and the main body 12. The other end of the vacuum pipe 64 connected to 62 is connected. A motor-driven control valve 66 is provided in the middle of the vacuum pipe 64 and is controlled by the control unit 50.
  Further, since the vacuum pump 62 sucks water vapor in the sterilization chamber 16, a water-sealed vacuum pump can be preferably used.
  Of the components constituting the steam sterilizer 60, the same components as those in the steam sterilizer 10 shown in FIG.
[0018]
  When steam sterilizing an object to be sterilized using the steam sterilizer 60, first, the vacuum pump 62 is driven and the control valve 66 is opened with the control valve 32 of the steam extraction pipe 30 closed. While the inside of the sterilization chamber 16 is in a depressurized state, the control valve 38 of the air supply pipe 42 is opened, hot air heated by the heater 40 is blown into the sterilization chamber 16, and the sterilization chamber 16 and the object to be sterilized are preheated.
  Furthermore, the control valve 27 is opened, and water is supplied from the water supply tank 26 to the water storage unit 20 via the water supply pipe 28. This water supply is performed until the stored water detection sensor FL detects it.
  Thereafter, the control valve 66 is closed and the interior of the sterilization chamber 16 is further depressurized. Then, the stored water stored in the water storage section 20 is heated by the heater 22 to generate water vapor, and the interior of the sterilization chamber 16 is filled with water vapor. .
  When the sterilization chamber 16 is filled with water vapor and the measured value of the pressure sensor P becomes equal to the atmospheric pressure, the control valve 32 is controlled by the control unit 50 according to the procedure shown in FIG. Since the subsequent procedure is the same as that of the steam sterilization apparatus 10, detailed description is abbreviate | omitted.
  Since the steam sterilizer 60 is provided with a vacuum pump 62, in the drying process, the vacuum pump 62 is driven to depressurize the interior of the sterilization chamber 16, and the interior of the sterilization chamber 16 is depressurized. The operation of opening the control valve 38 of the air supply pipe 42 and supplying the hot air heated by the heater 40 into the sterilization chamber 16 can be repeated in order to heat the object to be sterilized whose temperature has been lowered by the latent heat of vaporization. For this reason, the process time of a drying process can be shortened compared with the steam sterilizer 10.
[0019]
  FIG. 6 shows a pattern of the internal temperature and internal pressure of the sterilization chamber 16 of the steam sterilization apparatus 60 shown in FIG. In FIG. 6, when the measured value of the pressure sensor P becomes equal to the atmospheric pressure, the pressure increasing operation for increasing the pressure in the sterilization chamber 16 and the pressure decreasing operation for decreasing the pressure are performed according to the procedure shown in FIG. Here, an upper limit pressure (set high pressure side pressure P_H), Lower limit pressure in pressure reduction operation (set low pressure P_L), And α, β, γ, and δ were set to the same values as shown in FIG.
  FIG. 7 shows changes in the pressure and temperature of the sterilization chamber 16 due to the pressure increase operation and the pressure decrease operation. As shown in FIG. 7, the interior of the sterilization chamber 16 was replaced with water vapor by repeating each of the pressure increasing operation and the pressure decreasing operation in the sterilization chamber 16 three times.
  That is, the current temperature (measured high-pressure side temperature T in the third step-up operation)_H3) Is the previous temperature (measured high-pressure side temperature T) in the second step-up operation._H2) And T_H3Saturated water vapor temperature (T_HB) And a current temperature (measured low-pressure side temperature T) in the third step-down operation._L3) Is the previous temperature (measured low-pressure side temperature T) in the second step-down operation._L2) And T_L2Saturated water vapor temperature (T_LB) Is substantially the same temperature.
  As described above, in the steam sterilization apparatus 60 shown in FIG. 5, the interior of the sterilization chamber 16 is depressurized to the atmospheric pressure or lower and air is discharged in advance, and then water vapor is generated. Therefore, compared with the steam sterilization apparatus 10 shown in FIG. Thus, the interior of the sterilization chamber 16 could be sufficiently replaced with water vapor at an early stage.
[0020]
  1 to 7, the residual air in the sterilization chamber 16 can be sufficiently removed, and the sterilization chamber 16 can be set to a sterilization temperature / pressure. For this reason, even if an object to be sterilized such as linen that is difficult to be discharged is stored in the sterilization chamber 16, the residual air in the sterilization chamber 16 can be easily discharged.
  In addition, the presence or absence of residual air in the sterilization chamber 16 can be checked with a simple system.
  In addition, even if it is found that residual air exists in the sterilization chamber 16 while raising the internal temperature of the sterilization chamber 16, an operation of discharging the residual air before reaching the sterilization temperature / pressure is performed. The residual air can be quickly removed.
[0021]
【The invention's effect】
  According to the present invention, it can be easily confirmed in a short time that the steam replacement in the sterilization chamber is sufficiently performed, and the sterilization chamber can be surely set to the predetermined sterilization temperature and pressure. For this reason, the sterilization defect resulting from the temperature rise defect resulting from the residual air in the sterilization chamber can be prevented as much as possible, and the reliability of the sterilized material and the steam sterilization apparatus subjected to the steam sterilization can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of a steam sterilization apparatus according to the present invention.
FIG. 2 is a block diagram illustrating a configuration of a control unit illustrated in FIG.
FIG. 3 is a flowchart illustrating a control procedure of a control unit.
4 is a part of a chart showing a state in which a pressure increasing operation for increasing the pressure and a pressure decreasing operation for decreasing the pressure in the sterilization chamber of the steam sterilization apparatus shown in FIG.
FIG. 5 is a schematic diagram for explaining another example of the steam sterilization apparatus according to the present invention.
6 is a part of a chart showing a state in which a pressure increasing operation for increasing the pressure and a pressure decreasing operation for decreasing the pressure in the sterilization chamber of the steam sterilization apparatus shown in FIG. 5 are repeatedly performed.
7 is a part of a chart showing a state in which a pressure increasing operation for increasing the pressure and a pressure decreasing operation for decreasing the pressure in the sterilization chamber of the steam sterilization apparatus shown in FIG. 5 are repeatedly performed by the control unit.
FIG. 8 is a schematic view illustrating a conventional steam sterilization apparatus.
9 is a chart showing changes in temperature and pressure in the sterilization chamber of the steam sterilizer shown in FIG.
[Explanation of symbols]
  10,60 Steam sterilizer
  12 Body (pressure vessel)
  16 Sterilization room
  18 Mounting plate
  20 Water reservoir
  22 Heater
  30 Steam extraction piping
  32 Control valve (stopper valve)
  50 Control unit
  P Pressure sensor
  T temperature sensor

Claims (6)

Provided in the sterilization chamber of the main body portion as a pressure vessel, heats the water stored in the storage unit, heats the water stored in the storage unit, and generates water vapor in the sterilization chamber; In a steam sterilization apparatus comprising a stopper valve provided in a steam extraction pipe for discharging outside the sterilization chamber,
A pressure sensor for detecting the internal pressure of the sterilization chamber;
A temperature sensor for detecting the temperature of the sterilization chamber;
A memory in which an upper limit pressure and a lower limit pressure are stored in advance;
Comparing closing said stopper valve, the boost operation of heated-boosting the sterilization chamber by steam generated by being heated by the heating means, the measurement pressure measured by the pressure sensor, and a limit pressure that is stored in the memory And continue until the measured pressure matches the upper pressure limit;
Storing the temperature measured by the temperature sensor at this time in the memory as the measured high-pressure side temperature when the measured pressure matches the upper limit pressure;
Next, open the stopper valve and discharge the water vapor in the sterilization chamber together with air. Compare the measured pressure measured by the pressure sensor with the lower limit pressure stored in the memory, and the measured pressure matches the lower limit pressure. Step to continue until
Storing the temperature measured by the temperature sensor at this time in the memory as the measured low-pressure side temperature when the measured pressure matches the lower limit pressure;
Repeating the step of continuing the step-up operation, storing the measured high-pressure side temperature in a memory, continuing the step-down operation, and storing the measured low-pressure side temperature in a memory at least twice;
Calculating a temperature difference ΔT _H between the previous measured high pressure side temperature and the current measured high pressure side temperature ;
Calculating a temperature difference ΔT _L between the previous measured low pressure side temperature and the current measured low pressure side temperature ;
Comparing the value α stored in the memory in advance with the temperature difference ΔT _H ;
Comparing a value β stored in advance in memory with a temperature difference ΔT _L ;
If the relationship of ΔT _H ≦ α and ΔT _L ≦ β is not satisfied, the process returns to the step of repeating the pressure increasing operation and the pressure decreasing operation again.
When the relationship of ΔT _H ≦ α and ΔT _L ≦ β is satisfied, the temperature difference ΔT _HB between the measured high pressure side temperature and the saturated steam temperature when the upper limit pressure stored in advance in the memory is reached , Calculating the temperature difference ΔT _LB between the current measured low pressure side temperature and the saturated steam temperature when the lower limit pressure stored in advance in the memory is reached ;
Comparing the value γ stored in advance in memory with the temperature difference ΔT _HB ;
Comparing the value δ stored in advance in memory with the temperature difference ΔT _LB ;
If the relationship of ΔT _HB ≦ γ and ΔT _LB ≦ δ is not satisfied, the process returns to the step of repeating the step-up operation and the step-down operation again.
If the relationship of ΔT _HB ≦ γ and ΔT _LB ≦ δ is satisfied, it is determined that the sterilization chamber has been sufficiently replaced with water vapor, and the stopper valve is closed to bring the sterilization chamber to the desired sterilization pressure with saturated water vapor. A steam sterilization apparatus comprising a control unit that executes a step of increasing pressure to obtain a sterilization temperature / pressure .   The upper limit pressure and the lower limit pressure of the sterilization chamber controlled by the control unit are adjusted to be lower than the sterilization pressure for sterilizing the article to be sterilized inserted in the sterilization chamber and higher than the atmospheric pressure. The steam sterilizer according to claim 1.   The steam sterilizer according to claim 1 or 2, wherein a differential pressure between the upper limit pressure and the lower limit pressure is adjusted to be 0.02 MPa. Provided in the sterilization chamber of the main body portion as a pressure vessel, heats the water stored in the storage unit, heats the water stored in the storage unit, and generates water vapor in the sterilization chamber; A stopper valve provided in a steam extraction pipe for discharging outside the sterilization chamber, a pressure sensor for detecting the internal pressure of the sterilization chamber, a temperature sensor for detecting the temperature of the sterilization chamber, an upper limit pressure, and a lower limit pressure using steam sterilization apparatus including a memory which is stored, when subjected to steam sterilization to be sterilized that is inserted into the sterilization chamber,
Comparing closing said stopper valve, the boost operation of heated-boosting the sterilization chamber by steam generated by being heated by the heating means, the measurement pressure measured by the pressure sensor, and a limit pressure that is stored in the memory And continue until the measured pressure matches the upper pressure limit;
Storing the temperature measured by the temperature sensor at this time in the memory as the measured high-pressure side temperature when the measured pressure matches the upper limit pressure;
Next, open the stopper valve and discharge the water vapor in the sterilization chamber together with air. Compare the measured pressure measured by the pressure sensor with the lower limit pressure stored in the memory, and the measured pressure matches the lower limit pressure. Step to continue until
Storing the temperature measured by the temperature sensor at this time in the memory as the measured low-pressure side temperature when the measured pressure matches the lower limit pressure;
Repeating the step of continuing the step-up operation, storing the measured high-pressure side temperature in a memory, continuing the step-down operation, and storing the measured low-pressure side temperature in a memory at least twice;
Calculating a temperature difference ΔT _H between the previous measured high pressure side temperature and the current measured high pressure side temperature ;
Calculating a temperature difference ΔT _L between the previous measured low pressure side temperature and the current measured low pressure side temperature ;
Comparing the value α stored in the memory in advance with the temperature difference ΔT _H ;
Comparing a value β stored in advance in memory with a temperature difference ΔT _L ;
If the relationship of ΔT _H ≦ α and ΔT _L ≦ β is not satisfied, the process returns to the step of repeating the pressure increasing operation and the pressure decreasing operation again.
When the relationship of ΔT _H ≦ α and ΔT _L ≦ β is satisfied, the temperature difference ΔT _HB between the measured high pressure side temperature and the saturated steam temperature when the upper limit pressure stored in advance in the memory is reached , Calculating the temperature difference ΔT _LB between the current measured low pressure side temperature and the saturated steam temperature when the lower limit pressure stored in advance in the memory is reached ;
Comparing the value γ stored in advance in memory with the temperature difference ΔT _HB ;
Comparing the value δ stored in advance in memory with the temperature difference ΔT _LB ;
If the relationship of ΔT _HB ≦ γ and ΔT _LB ≦ δ is not satisfied, the process returns to the step of repeating the step-up operation and the step-down operation again.
If the relationship of ΔT _HB ≦ γ and ΔT _LB ≦ δ is satisfied, it is determined that the sterilization chamber has been sufficiently replaced with water vapor, and the stopper valve is closed to bring the sterilization chamber to the desired sterilization pressure with saturated water vapor. A steam sterilization method comprising the step of increasing the pressure to a sterilization temperature / pressure .   The steam sterilization method according to claim 4, wherein the upper limit pressure and the lower limit pressure of the sterilization chamber are lower than the sterilization pressure for sterilizing the article to be sterilized inserted in the sterilization chamber and higher than the atmospheric pressure.   The steam sterilization method according to claim 4 or 5, wherein a differential pressure between the upper limit pressure and the lower limit pressure is 0.02 MPa.

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