JPH023142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides, for example, when analyzing a liquid sample using an automatic chemical analyzer, the liquid sample filled in the measuring section is kept at a constant temperature (for example, 37°C) for a certain period of time.
This relates to a constant temperature device to meet the need to maintain temperature within ±0.5).

Generally, the purpose of temperature control using a constant temperature device is to maintain the temperature inside the measuring section at a set temperature. In this case, the factors that can be considered to affect the temperature of the constant temperature medium flowing into the measuring section are the outside temperature, heat generated by the motor for driving the pump for circulating the constant temperature medium, frictional heat generated by moving mechanical parts, electricity, etc. There is heat generated by the parts. Therefore,
For example, when the outside temperature is lower than the set temperature inside the measuring section, the constant temperature medium can be controlled to a predetermined temperature by controlling the drive of a separately attached constant temperature heater (hereinafter referred to as heater). Next, when the outside temperature rises and approaches the set temperature inside the measuring section (e.g. 37 ± 0.5°C), the constant temperature medium (usually water) filled in the measuring section will touch the high temperature part of the flow path. When passing through, it should normally be insulated, but instead it gets heated and flows into the measuring section, resulting in the temperature of the constant temperature medium inside the measuring section rising above the set temperature. This results in a disadvantage that temperature control accuracy is reduced. In addition, when the outside temperature and the set temperature inside the measuring section are close to each other, in addition to the influence of the outside temperature alone, the influence on the constant temperature medium such as the heat generated by the motor, mechanical heat, and heat generated by electrical components increases, and the set temperature inside the measuring section increases. control becomes difficult.

Therefore, in the past, operations such as insulating the flow path of the constant temperature medium flowing into the measuring section, cooling the heat source that generates heat, and further heating the constant temperature medium using a constant temperature heater were performed using a cold source that was used for both cooling and heating. It was done using a device. however,
First, it is difficult to insulate the circulating constant temperature medium in the entire flow path, and the constant temperature medium circulation pump, etc., is the heating element mentioned above on the one hand, and the constant temperature medium is always filled on the other hand, so it is difficult to insulate it. That becomes extremely difficult. In addition, when using a cooling device that performs both cooling and heating operations, it is possible to adjust the temperature by controlling the constant temperature heater on and off using both cooling and heating sensors. There is a pulsation width of the minimum temperature, and the stability of the control temperature is poor. Therefore, in the measurement section of a biochemical analyzer that is kept at a constant temperature, which requires highly accurate temperature control, even a slight temperature error can greatly affect the analytical measurement results. A constant temperature device is required to enable control.

The present invention improves the above-mentioned drawbacks, and uses a simple structure to improve control accuracy in a constant temperature device incorporated in a biochemical device, for example, and a constant temperature medium is flowed into a reaction tank to simplify operation. The object of the present invention is to provide a constant temperature device that performs highly accurate temperature control by first lowering the temperature of a constant temperature medium by providing a radiator before heating the medium, and then heating it with a heat exchanger.

An embodiment of the present invention will be described below with reference to the drawings.

Here, for the sake of explanation, a case will be described in which the constant temperature device of the present invention is incorporated into a biochemical analyzer.

In the figure, 1 is a glass measurement cell (hereinafter abbreviated as cell) into which a sample such as serum or urine is injected;
Cell 1 is measured colorimetrically by a photometer (not shown). Further, the inside of the cell 1 is divided into two parts: a part into which the specimen is injected, and a part into which the constant temperature water flows, so that the specimen and constant temperature water (constant temperature medium) do not mix. 2
3 is a pump for circulating constant temperature water inside the device, and 3 is a heat insulating tube for connecting the cell 1 and the pump 2. Reference numeral 4 designates a heat insulating tube connecting the pump 2 and a multi-fold meandering radiator 5 made of, for example, a copper tube for dissipating heat from the constant temperature medium. Next, the heat radiator 5 and a heat exchanger 6 for actually controlling the temperature of the constant temperature medium are connected by a heat insulating tube 7. The heat exchanger 6 is equipped with a constant temperature heater 8 for heating constant temperature water in the heat exchanger 6 and a sensor 9 for measuring the constant temperature water temperature in the heat exchanger 6. Further, in order to control the amount of heat radiated from the constant temperature water in the radiator 5, a fan 10 is provided at a position that evenly blows cooling air to the radiator 5. The heater 8, sensor 9, and fan 10 described above are each connected to a control circuit 11 to control them. The heat exchanger 6 is connected to the cell 1 by an insulating tube, so that the cell 1 → pump 2 → radiator 5 →
A closed constant-temperature water circulation path from heat exchanger 6 to cell 1 is formed.

Next, to explain the operation, the sensor 9 installed in the heat exchanger 6 is affected by the outside temperature and detects the temperature of the incoming constant temperature medium. When the control circuit 11 determines that there is a difference of 10°C or more between the outside temperature and the set temperature of the constant temperature medium based on the measured temperature of the medium, the constant temperature medium is heated by the heater 8 provided in the heat exchanger 6. The sample is kept at a constant temperature by flowing into the cell 1, and then the sample is kept at a constant temperature by the pump 2.
The constant temperature medium is returned to the heat exchanger 6 at a temperature lower than the set temperature in the range of 0.1°C to 1.0°C due to natural heat dissipation there. Here, the constant-temperature medium is heated and kept at a constant temperature by the heater 8 again, and then flows out into the cell 1. Next, similar detection is performed and the outside temperature rises and the difference between the set temperature and the set temperature is about 10℃.
When it is determined that the following conditions exist, the control circuit 11 outputs an output signal to the fan 10 to drive the fan 10 based on the output of the sensor 9 provided in the heat exchanger 6. ,
Outside air is sucked in and blown onto the radiator 5. The air blown from the fan 10 removes heat from the radiator 5, thereby cooling the constant temperature medium filled inside. The amount of heat radiated from the radiator 5 can be adjusted by adjusting the amount of air sent out from the fan 10. That is, the rotation speed of the fan 10 is controlled by the control circuit 11.
After the constant temperature medium is cooled to a low temperature in the range of about 0.1 to 1.0°C below the set temperature, it flows out into the heat exchanger 6 again, and then flows into the heat exchanger 6 until it reaches the set temperature. It is heated by the provided heater 8 and flows into the cell 1.

According to the constant temperature device of the present invention as described above, the temperature is maintained by the fan-equipped radiator provided before the heat exchanger so that the constant temperature medium temperature and the set temperature have a temperature difference in the range of about 0.1°C to 1.0°C. The medium temperature is controlled and the heater installed in the heat exchanger performs continuous control to only heat up to the set temperature.
This allows highly accurate temperature control. In other words, the constant temperature medium flowing into the heat exchanger with a built-in constant temperature heater (the constant temperature medium flowing out from the measuring section by the circulation pump) is always kept at a temperature approximately below the set temperature.
By realizing a temperature difference in the range of 0.1°C to 1.0°C using a radiator and continuously heating it using the heater, a quadratic curve can be created smoothly without the pulsation that occurs when controlling the heater on and off as described above. According to this, the temperature of the constant temperature medium can be asymptotically approached to the set temperature with high accuracy. Further, the amount of heat radiated by the radiator can be adjusted by adjusting the amount of air blown by a fan to the radiator based on the value detected by a temperature measurement sensor provided in the heat exchanger. Since this adjustment of the air volume does not require much precision, a simple structure as in the present invention is sufficient.

[Brief explanation of drawings]

The figure is a schematic configuration diagram for explaining an embodiment of the constant temperature device according to the present invention. 1... Cell, 2... Circulation pump, 3, 4,
7, 12...Insulation tube, 5...Radiator, 6...
...Heat exchanger, 8...Heater for constant temperature heating, 9...
Constant temperature medium temperature measurement sensor, 10...fan,
11...Control circuit.

Claims (1)

[Claims] 1. A circulation pump that circulates a constant temperature medium around the measurement part to be kept at a constant temperature via a first insulation tube, a radiator connected to this circulation pump by a second insulation tube, and A heat exchanger connected by a radiator and a third insulating tube, a temperature sensor built into the heat exchanger, a heater for heating a constant temperature medium, and the heat exchanger and the measuring section are connected. a fourth heat insulating tube; and a control circuit for controlling a fan for supplying cooling air to the heater for heating the constant temperature medium and the radiator according to the output from the sensor; The operation of the fan is controlled so that the temperature of the constant temperature medium flowing into the heat exchanger is always lowered to a set temperature or less by the radiator, and then the temperature is raised to the set temperature by continuous heating in the heat exchanger. A constant temperature device characterized by: