A light chamber hybrid heating and cooling constant temperature system

Abstract

The present invention discloses a light chamber hybrid heating, cooling and constant temperature system, which is arranged beside a combustion chamber and comprises a light chamber, a plurality of heating components, a temperature sensor and a heat-insulating material, wherein the heating components are arranged on the outer surface of the light chamber, a copper tube is arranged on the heating components, a heat exchange control module is arranged on one side of the copper tube, and the heating components close to the combustion chamber are semiconductor refrigeration sheets; a room temperature sensor for detecting the ambient temperature outside the light chamber is arranged on the outer side of the light chamber, and a connection temperature sensor for detecting the temperature at the connection between the light chamber and the combustion chamber is arranged, and the operation of each heating component is controlled individually after judging the signals detected by the temperature sensor, the room temperature sensor and the connection temperature sensor; the semiconductor heating and cooling belongs to the heat exchange components, so the heat exchange needs to be carried out through the copper tube and the water flow in the copper tube to make the temperature in the light chamber uniform and constant.

Description

Technical Field

[0001] The invention belongs to the field of spectrometers and relates to a constant temperature system, in particular to a light chamber hybrid heating and cooling constant temperature system. Background Art

[0002] At present, the common greenhouse constant temperature method for spectrometers on the market is the constant temperature of the heating element. The best constant temperature of the light chamber of the ICP instrument is 28-35℃. This method has a slow constant temperature speed and can only be used for single heating. The heating time and temperature stabilization time are very long, and the temperature stability is not high. After long-term operation of the instrument, it is easy to cause the temperature of the light chamber close to the combustion chamber to continue to rise. The temperature rise is higher than the constant temperature, which makes the constant temperature invalid and has a great impact on the measurement error of the spectrometer. In order to further reduce the measurement error and ensure the uniformity of the temperature of the entire light chamber, a semiconductor light chamber heating and cooling constant temperature system is specially designed. Summary of the invention

[0003] The purpose of the present invention is to solve the above problems in the prior art and to propose a light chamber hybrid heating and cooling constant temperature system.

[0004] To achieve the above purpose, the following technical scheme can be used to achieve this: a light chamber hybrid heating, cooling and constant temperature system, used in an ICP spectrometer, arranged next to a combustion chamber, including a light chamber, a plurality of heating components, temperature sensors arranged corresponding to the heating components, and thermal insulation materials arranged outside the light chamber, wherein the heating components are arranged on the outer surface of the light chamber, a copper tube is arranged on the heating components, a heat exchange control module is arranged on one side of the copper tube, and the heating components close to the combustion chamber are semiconductor refrigeration plates; a room temperature sensor for detecting the ambient temperature outside the light chamber is arranged outside the light chamber, and a connection temperature sensor for detecting the temperature at the connection between the light chamber and the combustion chamber is arranged, and the operation of each heating component is controlled individually after judging the signals detected by the temperature sensor, the room temperature temperature sensor and the connection temperature sensor.

[0005] More specifically, the heat exchange control module includes a conversion chip and a control unit. The conversion chip is used to receive signals and perform conversions, and the control unit outputs a PWM signal.

[0006] More specifically, each of the temperature sensors outputs a feedback signal, which is transmitted via a bus and finally received by the control unit for weighted optimization calculation. The weighted optimization calculation result is transmitted to the heating element and controls the adjustment of the heating state.

[0007] More specifically, the weighted optimization calculation formula is:

[0008] V1=K11*T1+K12*T2+K13*T3+K14*T4...+K1n*Tn;

[0009] V2=K21*T1+K22*T2+K23*T3+K24*T4...+K2n*Tn; ......

[0011] Vn=Kn1*T1+Kn2*T2+Kn3*T3+Kn4*T4...+Knn*Tn;

[0012] Wherein, Vn is the voltage required to be applied to the nth heating element after weighted optimization;

[0013] The weighted coefficient Knn is calculated by the thermal analysis software Flotherm through modeling, and then the value is corrected in multiple experimental tests;

[0014] Tn=Tk-Tx+Kt;

[0015] Where Tk is the set target constant temperature, Tx is the temperature detected by the temperature sensor at position n, and Kt is the heat dissipation compensation coefficient.

[0016] More specifically, the heat dissipation compensation coefficient Kt=(Tk-Ta) / n, wherein Tk is the set target constant temperature, Ta is the ambient temperature detected by the room temperature sensor, and n is the number of heating components.

[0017] Specifically, when Ta-Tk>Tk and Tn≤0.5°C, the semiconductor refrigeration piece switches to the cooling mode, and the voltage Vn' required after the switch is

[0018] Vn'=Kb*(Ta-Tk)+2.6-Vn,

[0019] Among them, Kb is the influence coefficient of the temperature Tb at the temperature sensor at the connection on the semiconductor refrigeration plate.

[0020] More specifically, the light chamber has a bottom surface, a top surface and side surfaces, the bottom surface is partially concave to form a support portion, the top surface is a plane, the side surfaces are between the bottom surface and the top surface, and the heating components are arranged on the top surface and the side surfaces of the light chamber.

[0021] More specifically, the heating element disposed on the top surface of the light chamber is connected via a copper tube, and the heating element disposed on the side surface of the light chamber is connected via a copper tube, and the two copper tubes do not contact each other.

[0022] More specifically, the plurality of heating components are controlled by independent PWM signals.

[0023] More specifically, there are 20 heating components, of which 4 are semiconductor cooling plates.

[0024] The present invention provides a light chamber hybrid heating and cooling constant temperature system, which can achieve the following technical effects:

[0025] 1. Semiconductor heating and cooling components are installed at multiple locations outside the optical chamber, and temperature sensors are installed in corresponding areas inside the optical chamber;

[0026] 2. Each heating component is independently PWM controlled, and each semiconductor component is independently PWM controlled. The H-bridge is then converted into a corresponding DC voltage through a modulation circuit to drive the semiconductor module, thereby quickly adjusting the temperature of each area;

[0027] 3. Because semiconductor heating and cooling are heat exchange components, heat exchange is required through copper tubes and water flow in the copper tubes to make the temperature in the light room uniform and constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the top view of the structure of the present invention;

[0029] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention viewed from top to bottom;

[0030] Figure 3 It is a three-dimensional mechanism schematic diagram of the present invention viewed from bottom to top.

[0031] In the figure: 1. Optical chamber; 2. Heating components; 3. Semiconductor cooling plate; 4. Support part; 5. Copper tube; 6. Heat exchange control module; 7. Insulation material. DETAILED DESCRIPTION

[0032] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 , Figure 2 and Figure 3 In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0034] The optical chamber hybrid heating and cooling constant temperature system described in the present invention is applied to an ICP spectrometer and is arranged next to a combustion chamber. Figure 1 , Figure 2 and Figure 3As shown, it includes a light chamber 1, a plurality of heating elements 2, temperature sensors arranged corresponding to the heating elements 2, and a heat-insulating material 7 arranged on the outside of the light chamber 1, the light chamber 1 has a top surface, a bottom surface and a side surface, the bottom surface is partially concave to form a support portion 4, the top surface is a plane, and the side surface is between the top surface and the bottom surface, the heating elements 2 are arranged on the outer surface of the light chamber 1, and more specifically, the heating elements 2 are respectively arranged on the top surface and the side surface of the light chamber 1, the heating elements 2 arranged on the side surface of the light chamber 1 are arranged around the light chamber 1, and the heating elements 2 arranged on the top surface of the light chamber 1 are arranged in a circle according to the shape of the top surface of the light chamber 1, and a copper tube 5 is arranged on the heating element 2, and water is arranged in the copper tube 5 for heat exchange, and more specifically, the heating elements 2 on the side surface and the heating elements 2 on the top surface of the light chamber 1 are both provided with copper tubes 5, and the copper tube 5 connects all the heating elements of this plane. A heating element 2, the two copper tubes 5 do not contact each other; a heat exchange control module 6 is arranged on one side of the copper tube 5, and the heat exchange control module 6 is arranged on the outside of the hybrid heating and cooling constant temperature system of the optical chamber. In the present invention, the heat exchange control module 6 contains a conversion chip and a control unit; the heating element 2 close to the combustion chamber side is a semiconductor refrigeration sheet 3. Specifically, 20 heating elements are arranged, among which there are 4 semiconductor refrigeration sheets. The semiconductor refrigeration sheets 3 heat when powered on and cool on the back, and cool and heat on the back when reversely powered on; a room temperature sensor for detecting the ambient temperature outside the light chamber 1 is arranged on the outside of the light chamber 1, and a connection temperature sensor for detecting the temperature at the connection between the light chamber 1 and the combustion chamber is arranged, and the operation of each heating element 2 is controlled separately after judging the signals detected by the temperature sensor, the room temperature temperature sensor and the connection temperature sensor.

[0035] The feedback signal of the temperature sensor is amplified by the amplifier and then enters the ADC conversion chip. The converted signal digital value is transmitted to the control unit - the single-chip microcomputer. The control unit in the heat exchange control module 6 transmits the signal through the CAN bus communication. The control unit performs weighted calculation on all the collected temperature data.

[0036] According to some embodiments of the present invention, the number of the heating components 2 and the number of the temperature sensors are both n, and the weighted optimization calculation formula is:

[0037] V1=K11*T1+K12*T2+K13*T3+K14*T4...+K1n*Tn;

[0038] V2=K21*T1+K22*T2+K23*T3+K24*T4...+K2n*Tn; ......

[0040] Vn=Kn1*T1+Kn2*T2+Kn3*T3+Kn4*T4...+Knn*Tn;

[0041] Wherein, Vn is the voltage required to be applied to the nth heating element 2 after weighted optimization;

[0042] The weighted coefficient Knn is calculated by the thermal analysis software Flotherm through modeling, and then the value is corrected in multiple experimental tests;

[0043] Tn=Tk-Tx+Kt, where Tk is the set target constant temperature, Tx is the temperature detected by the temperature sensor at position n, and Kt is the heat dissipation compensation coefficient;

[0044] A room temperature sensor is set in the system to detect the ambient temperature Ta outside the light chamber, and a connection temperature sensor is set outside the light chamber near the combustion chamber to detect the temperature Tb at that position, Kt = (Tk-Ta) / n; for example, if the target constant temperature Tk = 30 ° C, the external room temperature Ta = 20 ° C, and the heating element 2n = 20, then Kt = 0.5,

[0045] Among the n heating components 2, there are 4 semiconductor cooling sheets 3. When Ta-Tk>Tk and Tn≤0.5℃, it means that the heat dissipation rate is less than the heating rate. At this time, the 4 semiconductor cooling sheets 3 are switched to the cooling mode. The voltage Vn' required after the switching is:

[0046] Vn'=Kb*(Ta-Tk)+2.6-Vn,

[0047] Among them, Kb is the influence coefficient of the temperature Tb at the temperature sensor at the connection on the semiconductor refrigeration plate 3. The influence coefficient is the transfer coefficient of the heat conduction process, which is calculated by the thermal analysis software Flotherm and derived by the specific heat coefficient, thermal conductivity and density of the material. In practice, 0.2 is used.

[0048] For the heating element 2, the voltage is between 0-2.5V (for the heating element 2, if the calculated value of Vn is >2.5V, the set voltage is still 2.5V), corresponding to the heating power with a duty cycle of 0-100%. If the current temperature sensor measures the temperature Tx as 20°C and the target constant temperature Ta is 30°C, then Vn is calculated to be 2.5V, which is equivalent to setting full-power heating. If the current temperature sensor measures the temperature Tx as 29.9°C and the target constant temperature Ta is 30°C, then Vn is calculated to be 0.1V, which is equivalent to 4% low-power heating to maintain a constant temperature.

[0049] For the unit of the semiconductor refrigerator 3, 0-2.5V corresponds to a heating power with a duty cycle of 0-100%, and 2.6V-4.6V corresponds to a cooling power of 0-40% (the actual measured cooling power is about 20% at most to meet the constant temperature requirement). 2.5V-2.6V is an intermediate buffer set based on long-term measurements in actual use to avoid damage to the semiconductor refrigerator 3 due to frequent switching of heating and cooling near the critical point voltage.

[0050] Each heating element 2 is independently PWM controlled, and each semiconductor cooling plate 3 is independently PWM controlled. The H-bridge is then converted into a corresponding DC voltage through a modulation circuit to drive the semiconductor cooling plate 3, so that the temperature of each area can be quickly adjusted. The control unit finally obtains the PWM control signal of each control unit based on the result of weighted calculation and combined with the PID control principle to achieve optimal control of constant temperature.

[0051] Because the semiconductor refrigeration chip 3 is a heat exchange module, the back side is cooled when heating, and the back side is cooled and heated when reverse power is applied. In the initial stage of heating and constant temperature, the heating element 2 and the semiconductor refrigeration chip 3 are heated simultaneously according to the empirical PID value, and the heat is transferred to the back side of the semiconductor refrigeration chip 3 through the back copper tube 5 and the water flow to make the greenhouse temperature rise uniform. At this stage, although the semiconductor refrigeration chip 3 in the entire constant temperature system is heated on the front side, it is cooled on the back side, so its actual role in the entire system is to efficiently transfer the heat of other heating modules in the entire system to maintain the uniform temperature rise of the system. In fact, only the heating element 2 generates heat in the entire system. In the heating to constant temperature stage, the central control unit of the heat exchange control module 6 collects the temperature data of each part for weighted calculation and compares the empirical value to perform constant temperature PID control and adjustment. During long-term operation, when the temperature of the optical chamber 1 near the combustion chamber side rises above the constant temperature, the semiconductor refrigeration chip 3 is controlled to supply reverse power for low-power refrigeration. Since the back of the semiconductor refrigeration chip 3 is heated at this time, the heat needs to be transferred to other parts of the optical chamber 1 through the copper tube 5. Therefore, the semiconductor refrigeration chip 3 in the whole system is equivalent to supplying the excess heat of the optical chamber 1 near the combustion chamber side to other heating components 2 in the optical chamber 1 through high-efficiency heat transfer. At this time, the heat exchange control module 6 is needed to control the other heating components 2 to adjust the heating PID according to the empirical value to maintain the uniform constant temperature effect of the whole system.

[0052] like Figure 2 and Figure 3 As shown, the outside of the optical chamber 1 is also wrapped with a heat-insulating material 7 to reduce the heat loss in the system and ensure the temperature stability of the optical chamber 1.

[0053] The present invention adopts heating components 2 and semiconductor cooling sheets 3 installed at multiple positions of the optical chamber 1, so that the surrounding of the entire optical chamber 1 can be heated at the same time. At the same time, on the side close to the combustion chamber, heating and cooling can be performed by setting semiconductor cooling sheets 3. The temperature sensor in the corresponding area inside the optical chamber 1 feeds back the temperature value to the control unit in real time. After the control unit collects the information of all temperature sensors, it performs weighted optimization calculation, and then gives the PWM control PID parameter signal of each heating component 2 according to the PID control principle, so as to ensure that the entire optical chamber 1 can be quickly and evenly heated while ensuring the temperature stability of the optical chamber 1 during long-term operation. The thermal insulation material 7 wrapped around the outside of the entire optical chamber 1 reduces the loss of heat and improves the efficiency of heating and constant temperature. The temperature stability of the optical chamber 1 can be maintained within ±0.1°C, and the temperature uniformity of the hottest and coldest ends of the optical chamber 1 after long-term operation can be maintained within ±0.2°C, reducing the measurement error caused by the uneven change of the overall temperature of the optical chamber 1.

[0054] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A light chamber hybrid heating and cooling constant temperature system, applied in an ICP spectrometer, arranged beside a combustion chamber, comprising a light chamber (1), a plurality of heating elements (2), temperature sensors arranged corresponding to the heating elements (2), and a heat preservation material (7) arranged outside the light chamber (1), wherein the heating elements (2) are arranged on the outer surface of the light chamber (1). Features: A copper tube (5) is arranged on the heating element (2), a heat exchange control module (6) is arranged on one side of the copper tube (5), and the heating element (2) close to the combustion chamber is a semiconductor cooling plate (3); a room temperature sensor for detecting the ambient temperature outside the light chamber (1) is arranged outside the light chamber (1), and a connection temperature sensor for detecting the temperature at the connection between the light chamber (1) and the combustion chamber is arranged, and the operation of each heating element (2) is controlled individually after judging the signals detected by the temperature sensor, the room temperature sensor and the connection temperature sensor; The heat exchange control module (6) contains a conversion chip and a control unit. The conversion chip is used to receive signals and perform conversions. The control unit outputs a PWM signal. Each temperature sensor outputs a feedback signal. The signal is transmitted via a bus and finally received by the control unit for weighted optimization calculation. The weighted optimization calculation result is transmitted to the heating component and controls the heating state. The weighted optimization calculation formula is: V1=K11*T1+K12*T2+K13*T3+K14*T4...+K1n*Tn; V2=K21*T1+K22*T2+K23*T3+K24*T4...+K2n*Tn; ...... Vn=Kn1*T1+Kn2*T2+Kn3*T3+Kn4*T4...+Knn*Tn; Wherein, Vn is the voltage required to be applied to the nth heating element (2) after weighted optimization; The weighting coefficient Knn is calculated by the thermal analysis software Flotherm through modeling, and then the value is corrected in multiple experimental tests; Tn=Tk-Tx+Kt; Where Tk is the set target constant temperature, Tx is the temperature detected by the temperature sensor at position n, and Kt is the heat dissipation compensation coefficient; The heat dissipation compensation coefficient Kt=(Tk-Ta) / n, wherein Tk is the set target constant temperature, Ta is the ambient temperature detected by the room temperature sensor, and n is the number of heating components (2); When Ta-Tk>Tk and Tn≤0.5℃, the semiconductor refrigeration piece (3) switches to the cooling mode, and the voltage Vn' required after the switching is Vn'=Kb*(Ta-Tk)+2.6-Vn, Wherein, Kb is the influence coefficient of the temperature Tb at the temperature sensor at the connection point on the semiconductor cooling plate (3).

2. The light chamber hybrid heating and cooling constant temperature system according to claim 1, Features: The light chamber (1) has a bottom surface, a top surface and side surfaces, the bottom surface is partially concave to form a support portion (4), the top surface is a plane, and the side surfaces are between the bottom surface and the top surface. The heating element (2) is arranged on the top surface and the side surfaces of the light chamber (1).

3. The light chamber hybrid heating and cooling constant temperature system according to claim 2, Features: The heating element (2) arranged on the top surface of the light chamber (1) is connected via a copper tube (5), and the heating element (2) arranged on the side surface of the light chamber (1) is connected via a copper tube (5), and the two copper tubes (5) do not contact each other.

4. The light chamber hybrid heating and cooling constant temperature system according to claim 1, Features: The plurality of heating elements (2) are all controlled by independent PWM signals.

5. The light chamber hybrid heating and cooling constant temperature system according to claim 1, Features: The number of the heating components (2) is 20, of which the number of the semiconductor cooling sheets (3) is 4.

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