Air dry heat type high-temperature sterilizer

Abstract

The utility model relates to the technical field of high-temperature sterilization equipment, in particular to an air dry heat type high-temperature sterilizer which comprises a heating section, a heat exchange section and a cooling section, the heating section comprises a heating outer pipe, a heating inner pipe and an electric heating bar, the heating inner pipe is sleeved with the heating outer pipe, the electric heating bar is inserted into the heating inner pipe, and the heat exchange section is connected with the cooling section. The heat exchange section comprises a heat exchange inner pipe and a heat exchange outer pipe, the cooling section comprises a cooling inner pipe and a cooling outer pipe, one end of the heat exchange outer pipe is provided with an air inlet, the other end of the heat exchange outer pipe is connected with the heating inner pipe, one end of the heat exchange inner pipe is connected with the heating outer pipe, and the other end of the heat exchange inner pipe is connected with one end of the cooling inner pipe. The other end of the cooling inner pipe is an air outlet, a cold water inlet is formed in one end, close to the air outlet, of the cooling outer pipe, and a cold water outlet is formed in the other end, close to the air inlet, of the cooling outer pipe. The sterilization device has the advantages of being good in sterilization effect, high in sterilization efficiency, free of an independent sterilization cavity, capable of directly acting on bacteria through high temperature, thorough in sterilization and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to high-temperature sterilization equipment technical field, specifically, an air dry heat type high-temperature sterilizer. BACKGROUND

[0002] It is known that the air used in biological fermentation is sterilized by sterilization equipment, generally by using a sterile filter for filtering, the sterile filter is internally provided with a filter element, the filter element filtering has a certain sterilization efficiency, cannot achieve 100% sterilization, and the filter element replacement is not timely or the filter element itself failure also brings the possibility of bacterial contamination, thereby causing the whole fermentation device to be contaminated, the conventional dry heat type sterilizer refers to placing the sterilization device in a closed chamber, then heating the air in the chamber to high temperature (above 250 DEG C) and stopping for a certain time to achieve the sterilization of the bacteria in the device and the air, the existing dry heat type sterilizer needs a separate sterilization chamber, directly heats the air in the sterilization chamber to high temperature, has the problems of different sterilization purposes, long sterilization time, discontinuous air, and poor sterilization effect, especially, the heated air needs to be cooled after sterilization, and the cooling also needs a certain time, therefore, the whole sterilization time is too long, and the sterilization effect is poor. SUMMARY

[0003] The present application aims at solving the above problems of the prior art, and provides an air dry heat type high-temperature sterilizer which has simple structure, good sterilization effect, high sterilization efficiency, does not need a separate sterilization chamber, directly acts on the bacteria by high temperature, is completely sterilized, and can continuously sterilize the air.

[0004] The technical scheme adopted by the present application to solve the technical problems is:

[0005] An air dry heat type high-temperature sterilizer, characterized in that the sterilizer comprises a heating section, a heat exchange section and a cooling section, the heating section comprises a heating outer tube, a heating inner tube and an electric heating rod, the heating inner tube is sleeved in the heating outer tube, and the electric heating rod is inserted into the heating inner tube, the heat exchange section comprises a heat exchange inner tube and a heat exchange outer tube, the heat exchange inner tube is inserted into the heat exchange outer tube, the cooling section comprises a cooling inner tube and a cooling outer tube, the cooling inner tube is inserted into the cooling outer tube, one end of the heat exchange outer tube is provided with an air inlet, the other end of the heat exchange outer tube is connected with the heating inner tube, one end of the heat exchange inner tube is connected with the heating outer tube, the other end of the heat exchange inner tube is connected with one end of the cooling inner tube, the other end of the cooling inner tube is an air outlet, one end of the cooling outer tube close to the air outlet is provided with a cold water inlet, and the other end of the cooling outer tube close to the air inlet is provided with a cold water outlet.

[0006] The two ends of the heating outer tube are respectively closed, one end of the heating inner tube is open and inserted into the bottom of the heating outer tube, the other end of the heating inner tube extends out of the heating outer tube and is provided with an air inlet, the air inlet is communicated with the heat exchange outer tube through a pipeline, the electric heating rod is inserted into the bottom of the heating inner tube through the heating inner tube extending out of the end of the heating outer tube, the heating outer tube on the same side of the air inlet is provided with an air outlet, and the air outlet is connected with the heat exchange inner tube of the heat exchange section through a connecting pipe.

[0007] The gap between the electric heating rod and the heating inner tube is a heating gap.

[0008] The heat exchange inner tube comprises a plurality of heat exchange inner straight pipes and a plurality of heat exchange inner elbow pipes, the first end and the tail of the plurality of heat exchange inner straight pipes are respectively connected with the heat exchange inner elbow pipes to form an S shape, the heat exchange outer tube comprises a plurality of heat exchange outer straight pipes and a plurality of heat exchange outer connecting pipes, the heat exchange outer straight pipes are sleeved on the outer sides of the heat exchange inner straight pipes, the first end and the tail of the plurality of heat exchange outer straight pipes are respectively connected with the heat exchange outer connecting pipes to form an S shape, one end of the heat exchange outer straight pipe at one end is provided with an air inlet, the heat exchange outer straight pipe at the other end is connected with the heating inner tube, the heat exchange inner straight pipe at the same position as the air inlet is connected with the cooling inner tube, and the heat exchange inner straight pipe at the other end is connected with the heating outer tube.

[0009] The heat exchange inner pipe and the heat exchange outer pipe are arranged on the same side of the heat exchange inner straight pipe and the heat exchange outer straight pipe.

[0010] The cooling inner tube comprises a plurality of cooling inner straight pipes and a plurality of cooling inner elbow pipes, the first end and the tail of the plurality of cooling inner straight pipes are respectively connected with the cooling inner elbow pipes to form an S shape, the cooling outer tube comprises a plurality of cooling outer straight pipes and a plurality of cooling outer connecting pipes, the cooling outer straight pipes are sleeved on the outer sides of the cooling inner straight pipes, the first end and the tail of the plurality of cooling outer straight pipes are respectively connected with the cooling outer connecting pipes to form an S shape, one end of the cooling outer pipe at one end is provided with a cold water inlet, the heat exchange outer pipe at the other end is provided with a cold water outlet, the outlet of the cooling inner straight pipe at the position of the cold water inlet is an air outlet, and the other end of the cooling inner straight pipe is connected with the heat exchange inner straight pipe through the cooling inner and outer pipes.

[0011] The application has the advantages of simple structure, good sterilization effect, high sterilization efficiency, no need for a separate sterilization chamber, direct high-temperature action on bacteria, complete sterilization, continuous sterilization of air and the like. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a structural schematic diagram of the application.

[0013] Figure 2 is a front view of Figure 1 . DETAILED DESCRIPTION

[0014] The application will be further described below with reference to the drawings:

[0015] As shown in the drawings, an air dry high-temperature sterilizer is characterized in that the sterilizer comprises a heating section 1, a heat exchange section 2 and a cooling section 3, the heating section 1 comprises a heating outer tube 4, a heating inner tube 5 and an electric heating rod 6, the heating inner tube 5 is sleeved in the heating outer tube 4, and the electric heating rod 6 is inserted into the heating inner tube 5, the heat exchange section 2 comprises a heat exchange inner tube 7 and a heat exchange outer tube 8, the heat exchange inner tube 7 is inserted into the heat exchange outer tube 8, the cooling section 3 comprises a cooling inner tube 9 and a cooling outer tube 10, the cooling inner tube 9 is inserted into the cooling outer tube 10, one end of the heat exchange outer tube 8 is provided with an air inlet 11, the other end of the heat exchange outer tube 8 is connected with the heating inner tube 5, one end of the heat exchange inner tube 7 is connected with the heating outer tube 4, the other end of the heat exchange inner tube 7 is connected with one end of the cooling inner tube 9, and the other end of the cooling inner tube 9 is an air outlet 12, one end of the cooling outer tube 10 close to the air outlet 12 is provided with a cold water inlet 13, and the other end of the cooling outer tube 10 close to the air inlet 11 is provided with a cold water outlet 14.

[0016] Further, both ends of the heating outer tube 4 are closed, one end of the heating inner tube 5 is opened and inserted into the bottom of the heating outer tube 4, the other end of the heating inner tube 5 extends out of the heating outer tube 4 and is provided with an air inlet, the air inlet is communicated with the heat exchange outer tube 8 through a pipeline, the electric heating rod 6 is inserted into the bottom of the heating inner tube 5 through the heating inner tube 5 extending out of the end of the heating outer tube 4, the heating outer tube 4 on the same side of the air inlet is provided with an air outlet, and the air outlet is connected with the heat exchange inner tube 7 of the heat exchange section 2 through a connecting pipe.

[0017] Further, the gap between the electric heating rod 6 and the heating inner tube 5 is a heating gap.

[0018] Further, the heat exchange inner tube 7 comprises a plurality of heat exchange inner straight tubes 15 and a plurality of heat exchange inner elbow tubes 16, the first and last heat exchange inner straight tubes 15 are connected with the heat exchange inner elbow tubes 16 to form an S shape, the heat exchange outer tube 8 comprises a plurality of heat exchange outer straight tubes 21 and a plurality of heat exchange outer connecting tubes 22, the heat exchange outer straight tubes 21 are sleeved on the outside of the heat exchange inner straight tubes 15, the first and last heat exchange outer straight tubes 21 are connected with the heat exchange outer connecting tubes 22 to form an S shape, one end of the heat exchange outer straight tube 21 at one end is provided with the air inlet 11, the heat exchange outer straight tube 21 at the other end is connected with the heating inner tube 5, the heat exchange inner straight tube 15 at the same position as the air inlet 11 is connected with the cooling inner tube 9, and the heat exchange inner straight tube 15 at the other end is connected with the heating outer tube 4.

[0019] Further, the heat exchange inner and outer tubes are arranged on the same side of the heat exchange inner straight tube 15 and the heat exchange outer straight tube 21.

[0020] Furthermore, the cooling inner tube 9 includes a plurality of cooling inner straight tubes 17 and a plurality of cooling inner bent tubes 18, and the heads and tails of the plurality of cooling inner straight tubes 17 are respectively connected to the cooling inner bent tubes in an S shape. The cooling outer tube 10 includes a plurality of cooling outer straight tubes 19 and a plurality of cooling outer connecting tubes 20, and the cooling outer straight tubes 19 are sleeved on the outside of the cooling inner straight tubes 17, and the heads and tails of the plurality of cooling outer straight tubes 19 are respectively connected to the cooling outer connecting tubes 20 in an S shape, wherein one end of the cooling outer tube 10 is provided with a cold water inlet 13, and the heat exchange outer tube 8 at the other end is provided with a cold water outlet 14, and the outlet of the cooling inner straight tube 17 at the position of the cold water inlet 13 is an air outlet 12, and the other end of the cooling inner straight tube 17 is connected to the heat exchange inner straight tube 15 through the cooling inner and outer tubes.

[0021] The design method steps are as follows:

[0022] (1) Heat exchange section design method:

[0023] Step 1: First determine the original parameters of the heat exchange section working condition: inlet air pressure P1 (unit Pa), standard atmospheric pressure P0 (take 101325Pa), rated flow rate M0 under standard air condition (unit m 3 / s), air density ρ0 under standard conditions (take 1.293kg / m 3 ), air specific heat capacity Cp (take 1.3kJ / m 3 .℃), air dynamic viscosity μ1 (taken as 0.0000183Pa.s), air thermal conductivity λ1 (taken as 0.0296w / m.℃ when the average temperature of the tube is 170℃, and taken as 0.0389w / m.℃ when the average temperature of the annular gap is 210℃), air Prandtl number Pr1 (taken as 0.7239), air volume expansion coefficient β (taken as 3.676×10 -3 / ℃), the metal thermal conductivity coefficient λ0 of the heat exchange section pipe (3.0w / m.℃ for S30408 ​​and S31603 stainless steel), the tube inlet temperature t1 (20℃), and the design target parameters: tube outlet temperature t2 (320℃), annular seam inlet temperature t3 (360℃), and annular seam outlet temperature t4 (60℃);

[0024] The pipe process refers to the process inside the inner pipe, and the annular gap refers to the gap between the inner pipe and the outer pipe.

[0025] Step 2: Based on the parameters determined in step 1, calculate the air density ρ1 (unit: kg / m 3 ), ρ2 (unit kg / m 3 ),

[0026]

[0027] Step three: select a group of heat exchange tubes (according to the tube IS02037 standard series, or DIN11850 standard series) select two kinds of pipe materials, inner tube dw1 (unit m), inner tube wall thickness δ1 (unit m), outer tube Dw2 (unit m), outer tube wall thickness δ1 (unit m);

[0028] Step four: calculate the inner diameter of the inner tube dn1 (unit m), the outer diameter of the outer tube Dn2 (unit m), and the equivalent diameter of the ring de (unit m) according to the following formula, and calculate the average flow velocity W1 (unit m / s) of the tube and the average flow velocity W2 (unit m / s) of the ring according to the parameters determined in step two,

[0029] dn1 = dw1 - 2 × δ1

[0030] Dn2 = Dw2 - 2 × δ2

[0031] de = Dn2 - dw1

[0032]

[0033] Step five: calculate the heat exchange capacity Q1 (unit w) of the heat exchange section according to the following formula,

[0034] Q1 = Cp × M0 × (t2 - t1);

[0035] Step six: calculate the Reynolds number Re_1 (dimensionless) of the inner tube and the Reynolds number Re_2 (dimensionless) of the ring according to the following formula,

[0036]

[0037] Step seven: calculate the inner heat exchange coefficient α1 (unit w / m 2 .℃) of the tube according to the following formula,

[0038] Determination of heat exchange coefficient applicable formula:

[0039] (1) When Re1 < 2100, the tube size should be reduced to make Re1 > 2100;

[0040] (2) When 2100 < Re1 < 10000, use the following formula:

[0041]

[0042] (3) When Re1 > 10000, use the following formula:

[0043]

[0044] Step eight: calculate the outer ring heat exchange coefficient α2 (unit w / m 2 .℃) of the tube according to the following formula,

[0045] The values used in the calculation of the annular heat exchange coefficient: temperature difference Δt (take 60-20=40℃), gravitational acceleration g (take 9.81 kg / m.s2);

[0046] Determination of the heat exchange coefficient applicable formula:

[0047] (1) when 200 < Re2 < 2000, use the following formula:

[0048]

[0049] (2) when Re2 > 10000, use the following formula:

[0050]

[0051] (3) when 2000 < Re2 < 10000, take Re2 = 2000 and Re2 = 10000, and then according to the actual Re2 value using interpolation method to obtain;

[0052] (4) when Re2 < 200, the tube size should be reduced, according to the heat exchange section calculation method in step three, reselect the tube size, recalculate, until the requirements are met;

[0053] Step nine: calculate the heat transfer temperature difference ΔT1 (unit ℃), heat transfer coefficient K1 (unit w / m 2 .℃) according to the following formula,

[0054]

[0055] Step ten: according to the structure design, first take a certain length of the sleeve L 0-0 (unit m), then calculate the heat exchange area F1 (unit m 2 ), the total length of the sleeve L1 (unit m), the number of sleeves N 0-0 (dimensionless) according to the following formula,

[0056]

[0057] (2) cooling section design method:

[0058] Step one: first determine the cooling section working condition original parameters: water thermal conductivity λ2 (take 0.621 w / m. ℃), water dynamic viscosity μ2 (take 0.00131 Pa.s), water Prandtl number Pr2 (take 11.18), (water) coefficient n2 (take 0.4), air thermal conductivity λ1 (tube side average temperature 45 ℃, take 0.0278 w / m. ℃), tube side (air) inlet temperature t7=t2 (t2=60 ℃), and the designed target parameters: ring gap water inlet temperature t5 (take 5 ℃), ring gap water flow rate W4 (take 0.25 m / s), tube side outlet temperature t8 (take 30 ℃), tube side refers to the process inside the inner tube, and the ring gap refers to the gap between the inner tube and the outer tube,

[0059] Step two: according to the parameters determined in step one, the air density ρ3 (unit kg / m 3 ) is calculated according to the following formula,

[0060]

[0061] Step three: select two kinds of pipe materials (the same as the heat exchange section, inner tube dw1×δ1, outer tube Dw2×δ2),

[0062] Step four: according to the parameters determined in step one, the tube side flow rate W3 (unit m / s) is calculated,

[0063]

[0064] Step five: the heat exchange capacity Q2 (unit w) of the cooling section, the ring gap water flow M2 (unit m / s), and the ring gap water outlet temperature t6 (unit ℃) are calculated according to the following formula,

[0065] Q2=Cp×M0×(t7-t8)

[0066]

[0067]

[0068] Step six: the tube side Reynolds number Re3 (dimensionless) and the ring gap Reynolds number Re4 (dimensionless) are calculated according to the following formula,

[0069]

[0070] Step seven: the tube side inside heat exchange coefficient α3 (unit w / m 2 . ℃) is calculated according to the following formula,

[0071] Determination of heat exchange coefficient applicable formula:

[0072] (1) When Re3<2100, the pipe size should be reduced to make Re3>2100, and the pipe size is reselected according to step three in the method for calculating the cooling section, and the calculation is re-performed until the requirement is met;

[0073] (2) When 2100<Re3<10000, the following formula is used:

[0074]

[0075] (3) When Re3>10000, the following formula is used:

[0076]

[0077] Step eight: the outside ring joint heat exchange coefficient a4 (unit w / m 2 .℃) of the pipe is calculated according to the following formula;

[0078]

[0079] Step nine: the heat transfer temperature difference AT2 (unit ℃) and the heat transfer coefficient K2 (unit w / m 2 .℃) are calculated according to the following formula,

[0080]

[0081] Step ten: according to the structural design, a certain length L 0-1 of the sleeve pipe is first taken (generally, L 0-1 =L 0-0 , unit m), and then the heat exchange area F2 (unit m 2 ), the total length L2 (unit m) of the sleeve pipe, and the number N 0-1 of the sleeve pipes (dimensionless) are calculated according to the following formula,

[0082]

[0083] (Three), the calculation method of the air resistance of the sterilizer:

[0084] Step one: according to the structure, the original parameters of the working condition are first determined: the total number N1 (dimensionless) of the pipe bends in the heat exchange section and the cooling section, the pipe bend resistance coefficient ξ1 (0.18 is taken), the number N2 (dimensionless) of the ring joint turns in the heat exchange section, and the ring joint turn resistance coefficient ξ2 (2.2 is taken), the pipe bend is an inner bend pipe, and the number of the ring joint turns in the heat exchange section is the number of the outer connecting pipes,

[0085] Step two: according to the parameters determined in step one, the pipe bend friction resistance coefficient λ n1 in the heat exchange section, the pipe bend friction resistance coefficient λ n3 (dimensionless) in the cooling section, and the ring joint friction resistance coefficient λ t2Dimensionless), air friction resistance of tube pass ΔPzn (unit Pa), air friction resistance of annular gap of heat exchange section ΔPzt (unit Pa),

[0086] Step three: according to the parameters determined in step one, the total resistance coefficient of tube pass bend ∑ξ1 (dimensionless), the annular gap turning resistance coefficient ∑ξ2 (dimensionless), the local resistance of tube pass ΔPznjb (unit Pa), the local resistance of annular gap ΔPztjb (unit Pa) are calculated by the following formula,

[0087] ∑ξ1 = N1 × ξ1

[0088] ∑ξ2 = N2 × ξ2

[0089]

[0090] Step four: the total air resistance of sterilizer ∑ΔP (unit Pa) is calculated by the following formula,

[0091] ∑ΔP = (ΔPzn + ΔPzt + ΔPznjb + ΔPztjb) × 1.2,

[0092] Step five: the total air resistance of sterilizer ∑ΔP (unit Pa) is checked,

[0093] If the total air resistance of sterilizer ∑ΔP < 2% × P1, the selected pipe specification meets the requirements; if ∑ΔP ≥ 2% × P1, the pipe specification is reselected according to step three in the heat exchange section calculation method, and the calculation is reperformed until the requirements are met,

[0094] (Four), heating section residence time calculation method:

[0095] Step one: first select a certain specification of heating outer tube outer diameter Dtw (unit m), heating outer tube wall thickness δt (unit m), heating outer tube length H (unit m),,

[0096] Step two: according to the parameters determined in step one, the heating outer tube content volume Vt (unit m 3 ) is calculated by the following formula,

[0097]

[0098] Step three: the air residence time T (unit s) is calculated,

[0099]

[0100] Step four: the air residence time T (unit s) is checked,

[0101] If the air residence time T > 10 s, the heating outer tube volume meets the requirements.

[0102] The structure adopts the counterflow heat exchange technology, and high-temperature sterile air after sterilization needs to be cooled, so that the power consumption of the electric heating rod is greatly reduced, and the cooling heat efficiency of the cold cutting water is improved.

[0103] The total length of the heat exchange section, the total length of the cooling section and the heating section parameters can be adjusted according to the installation site to adjust the occupied space of the sterilizer.

[0104] The sterilizer has the advantages of simple structure, good sterilization effect, high sterilization efficiency, no need for a separate sterilization chamber, direct action of high temperature on bacteria, complete sterilization, continuous sterilization of air and the like.

[0105] The annular gap in the application refers to the gap between the inner tube and the outer tube, and the tube path refers to the travel inside the inner tube.

[0106] One embodiment of the method is as follows:

[0107] A design method of an air dry heat type high-temperature sterilizer, and the design method steps are as follows:

[0108] (I) Heat exchange section design method:

[0109] Step 1: First, determine the original parameters of the heat exchange section: inlet air pressure P1=303975 Pa, standard atmospheric pressure P0=101325 Pa, rated flow M0=50 L / min=0.0008333 m 3 / s, air density under standard conditions ρ0=1.293 kg / m 3 , air specific heat capacity Cp=1.3 kJ / m 3 .℃, air dynamic viscosity μ1=0.0000183 Pa.s, air thermal conductivity λ1(tube path average temperature 170℃, take 0.0296 w / m.℃, annular gap average temperature 210℃, take 0.0389 w / m.℃), air Prandtl number Pr1 take 0.7239, air volume expansion coefficient β=3.676×10 -3 / ℃, heat exchange section pipe material S31603 stainless steel, metal thermal conductivity λ0=3.0 w / m.℃, tube path inlet temperature t1=20℃, target parameters: tube path outlet temperature t2=320℃, annular gap inlet temperature t3=360℃, annular gap outlet temperature t4=60℃;

[0110] Step 2: According to the parameters determined in step 1, the air densities ρ1(unit kg / m 3 ), ρ2(unit kg / m 3 ) are calculated according to the following formula:

[0111]

[0112] Step three: select a set of heat exchange tube (according to the tube IS02037 standard series, or DIN11850 standard series) select two kinds of pipe material, inner tube dw1 (unit m), inner tube wall thickness δ1 (unit m), outer tube Dw2 (unit m), outer tube wall thickness δ2 (unit m), select a set of heat exchange tube, inner tube dw1=0.0254m, inner tube wall thickness δ1=0.0015m, outer tube Dw2=0.0381m, outer tube wall thickness δ2=0.0015m;

[0113] Step four: calculate the inner diameter of the inner tube dn1 (unit m), the inner diameter of the outer tube Dw2 (unit m), the equivalent diameter of the ring de (unit m) according to the formula, and calculate the average flow velocity W1 (unit m / s) of the tube, the average flow velocity W2 (unit m / s) of the ring according to the parameters determined in step two,

[0114] dn1= dw1-2×δ1=0.0254-2×0.0015=0.0224m

[0115] Dn2=Dw2-2×δ2=0.0381-2×0.0015=0.0351m

[0116] de=Dn2-dw1=0.0351-0.0254=0.0097m

[0117]

[0118] Step five: calculate the heat exchange capacity Q1 (unit w) of the heat exchange section according to the formula,

[0119] Q1=Cp×M0×(t2-t1)=1.3×1000×0.0008333×(320-20)=325w;

[0120] Step six: calculate the Reynolds number Re_1 (dimensionless) of the inner tube and the Reynolds number Re_2 (dimensionless) of the ring according to the formula,

[0121]

[0122] Step seven: calculate the heat transfer coefficient α1 (unit w / m 2 .℃) of the inner side of the tube according to the formula,

[0123] The thermal conductivity of air λ1 is 0.0296w / m.℃ when the average temperature of the tube is 170℃.

[0124] Determination of heat transfer coefficient applicable formula: when 2100<Re1=3335<10000, the following formula is used for calculation:

[0125]

[0126] Step eight: Calculate the annular gap heat transfer coefficient α2 (unit w / m 2 .℃) by the following formula:

[0127] The values used in the calculation of the annular gap heat transfer coefficient: temperature difference Δt (take 60-20=40℃), gravitational acceleration g (take 9.81 kg / m.s2);

[0128] Air thermal conductivity λ1 is taken as 0.0389 w / m.℃ at the average temperature of the tube 210℃; L 0-0 Take 0.7 m.

[0129] Determination of the heat transfer coefficient applicable formula: when 200 < Re2 = 1242 < 2000, use the following formula:

[0130]

[0131] Step nine: Calculate the heat transfer temperature difference ΔT1 (unit ℃), heat transfer coefficient K1 (unit w / m 2 .℃) by the following formula:

[0132] Step ten: According to the structural design, take the length of the sleeve L 0-0 =0.7 m, calculate the heat transfer area F1 (unit m 2 ), the total length of the sleeve L1 (unit m), the number of sleeves N 0-0 (dimensionless),

[0133]

[0134] According to the structural design, take N0-0=24;

[0135] (II) Cooling section design method:

[0136] Step one: First determine the original parameters of the cooling section working condition: water thermal conductivity λ2 (take 0.621 w / m.℃), water dynamic viscosity μ2 (take 0.00131 Pa.s), water Prandtl number Pr2 (take 11.18), (water) coefficient n2 (take 0.4), air thermal conductivity λ1 (tube average temperature 45℃ when take 0.0278 w / m.℃), tube (air) inlet temperature t7=t2 (t2=60℃), and the target parameters of the design: annular gap water inlet temperature t5 (take 5℃), annular gap water flow rate W4 (take 0.25 m / s), tube outlet temperature t8 (take 30℃),

[0137] Step two: According to the parameters determined in step one, calculate the air density ρ3 (unit kg / m 3),

[0138]

[0139] Step three: select two specifications of pipe (with the same heat exchange section, inner tube dw1 x δ1, outer tube Dw2 x δ2),

[0140] Step four: according to the parameters determined in step one, calculate the pipe flow rate W3 (unit m / s),

[0141]

[0142] Step five: calculate the heat exchange capacity Q2 (unit w) of the cooling section, the annular gap water flow M2 (unit m / s), the annular gap water outlet temperature t6 (unit ℃) according to the following formula,

[0143] Q2 = Cp x M0 x (t7-t8) = 1.3 x 1000 x 0.0008333 x (60-30) = 32.5w

[0144]

[0145] Step six: calculate the pipe Reynolds number Re3 (dimensionless) and the annular gap Reynolds number Re4 (dimensionless) according to the following formula,

[0146]

[0147] Step seven: calculate the inside heat exchange coefficient α3 (unit w / m 2 .℃) of the pipe according to the following formula,

[0148]

[0149] Step eight: calculate the outside annular gap heat exchange coefficient α4 (unit w / m 2 .℃) of the pipe according to the following formula;

[0150]

[0151] Step nine: calculate the heat transfer temperature difference ΔT2 (unit ℃) and the heat transfer coefficient K2 (unit w / m 2 .℃) according to the following formula,

[0152]

[0153]

[0154] Step ten: according to the structure design, take the sleeve length L 0-1 = L 0-0 = 0.7m, calculate the heat exchange area F2 (unit m 2 ), the total length of the sleeve L2 (unit m), and the number of sleeves N0-1 (dimensionless),

[0155]

[0156] Round up to get N0-1=2;

[0157] (3) Calculation method of sterilizer air resistance:

[0158] Step 1: Determine the original working parameters according to the structure: the total number of elbows in the heat exchange section and cooling section pipe N1 (dimensionless) N1 = N 0-0 +N 0-1 +1=27, pipe elbow resistance coefficient ξ1 (take 0.18), heat exchange section annular seam turning number N2 (dimensionless) N2=N 0-0 +1=25, annular gap steering resistance coefficient ξ2 (taken as 2.2).

[0159] Step 2: Calculate the friction coefficient λ of the heat exchange tube according to the parameters determined in step 1 n1 , cooling section pipe friction resistance coefficient λ n3 (dimensionless), friction resistance coefficient of the heat exchange section annular gap λ t2 (dimensionless), tube air friction resistance ΔPzn (unit Pa), heat exchange section annular gap air friction resistance ΔPzt (unit Pa), 1.

[0160]

[0161] Step 3: Based on the parameters determined in step 1, calculate the total resistance coefficient of the pipe elbow ∑ξ1 (dimensionless), the annular seam turning resistance coefficient ∑ξ2 (dimensionless), the pipe local resistance ΔPznjb (unit Pa), and the annular seam local resistance ΔPztjb (unit Pa).

[0162] ∑ξ1=N1×ξ1=27×0.18=4.86

[0163] ∑ξ2=N2×ξ2=25×2.2=55

[0164]

[0165] Step 4: Calculate the total air resistance ∑ΔP (unit: Pa) of the sterilizer according to the following formula:

[0166] ∑ΔP=1.2×(ΔPzn+ΔPzt+ΔPznjb+ΔPztjb)=1.2×(48.8+110.9+7.5+40.5)=249.2Pa,

[0167] Step five: check the total air resistance of sterilizer ∑ΔP (unit Pa),

[0168] The total air resistance of sterilizer ∑ΔP = 249.2 Pa < 2% × P1 = 2% × 303975 = 6079.5 Pa, so the selected pipe specifications meet the requirements,

[0169] (Four), the calculation method of heating section residence time:

[0170] Step one: according to the structure arrangement to take the heater cylinder outer diameter D tw = 0.133 m, the cylinder wall thickness δ t = 0.003 m, the heating cylinder length H = 0.7 m,

[0171] Step two: according to the parameters determined in step one, calculate the heating outer tube content volume Vt (unit m 3 ),

[0172]

[0173] Step three: calculate the air residence time T (unit s),

[0174]

[0175] Step four: check the air residence time T (unit s),

[0176] Air residence time T = 13.8 s > 10 s, the heating outer tube volume meets the requirements.

Claims

1. An air dry heat autoclave, characterized by The sterilizer comprises a heating section, a heat exchange section and a cooling section, the heating section comprises a heating outer tube, a heating inner tube and an electric heating rod, the heating inner tube is sleeved in the heating outer tube, and the electric heating rod is inserted into the heating inner tube, the heat exchange section comprises a heat exchange inner tube and a heat exchange outer tube, the heat exchange inner tube is inserted into the heat exchange outer tube, the cooling section comprises a cooling inner tube and a cooling outer tube, the cooling inner tube is inserted into the cooling outer tube, one end of the heat exchange outer tube is provided with an air inlet, the other end of the heat exchange outer tube is connected with the heating inner tube, one end of the heat exchange inner tube is connected with the heating outer tube, the other end of the heat exchange inner tube is connected with one end of the cooling inner tube, the other end of the cooling inner tube is an air outlet, one end of the cooling outer tube close to the air outlet is provided with a cold water inlet, and the other end of the cooling outer tube close to the air inlet is provided with a cold water outlet.

2. An air dry heat autoclave according to claim 1, characterized in that The two ends of the heating outer tube are closed, one end of the heating inner tube is open and inserted into the bottom of the heating outer tube, the other end of the heating inner tube extends out of the heating outer tube and is provided with an air inlet, the air inlet is communicated with the heat exchange outer tube through a pipeline, the electric heating rod is inserted into the bottom of the heating inner tube through the heating inner tube extending out of the end of the heating outer tube, an air outlet is arranged on the heating outer tube on the same side of the air inlet, and the air outlet is connected with the heat exchange inner tube of the heat exchange section through a connecting pipe.

3. An air dry heat autoclave according to claim 1, characterized in that The gap between the electric heating rod and the heating inner tube is a heating gap.

4. An air dry heat autoclave according to claim 1, characterized in that The heat exchange inner tube comprises a plurality of heat exchange inner straight tubes and a plurality of heat exchange inner elbow tubes, the first end and the tail of the plurality of heat exchange inner straight tubes are connected with the heat exchange inner elbow tubes to form an S shape, the heat exchange outer tube comprises a plurality of heat exchange outer straight tubes and a plurality of heat exchange outer connecting tubes, the heat exchange outer straight tubes are sleeved on the outer sides of the heat exchange inner straight tubes, the first end and the tail of the plurality of heat exchange outer straight tubes are connected with the heat exchange outer connecting tubes to form an S shape, one end of the heat exchange outer straight tube at one end is provided with an air inlet, the heat exchange outer straight tube at the other end is connected with the heating inner tube, the heat exchange inner straight tube at the same position as the air inlet is connected with the cooling inner tube, and the heat exchange inner straight tube at the other end is connected with the heating outer tube.

5. An air dry heat autoclave according to claim 4, characterized in that The heat exchange inner elbow tubes and the heat exchange outer connecting tubes are arranged on the same side of the heat exchange inner straight tubes and the heat exchange outer straight tubes.

6. An air dry heat autoclave according to claim 1, characterized in that The cooling inner tube comprises a plurality of cooling inner straight tubes and a plurality of cooling inner elbow tubes, the first end and the tail of the plurality of cooling inner straight tubes are connected with the cooling inner elbow tubes to form an S shape, the cooling outer tube comprises a plurality of cooling outer straight tubes and a plurality of cooling outer connecting tubes, the cooling outer straight tubes are sleeved on the outer sides of the cooling inner straight tubes, the first end and the tail of the plurality of cooling outer straight tubes are connected with the cooling outer connecting tubes to form an S shape, one end of the cooling outer tube at one end is provided with a cold water inlet, the heat exchange outer tube at the other end is provided with a cold water outlet, the outlet of the cooling inner straight tube at the position of the cold water inlet is an air outlet, and the other end of the cooling inner straight tube is connected with the heat exchange inner straight tube through the cooling inner and outer tubes.

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