Platinum electrode glass capsulation thermistor (NTC) microballon medical energy converter
Technical field: platinum electrode glass capsulation thermistor (NTC) microballon has the R/T characteristic, also have from thermal characteristics simultaneously, thereby platinum electrode glass capsulation thermistor (NTC) microballon medical energy converter is mainly used in two aspects: 1. medical temperature monitoring: cardiac muscle probe, body cavity temperature, fluid temperature (F.T.), hypodermic needle are popped one's head in; 2. self-heating analysis: the fluid flow of catheter and flow monitoring, blood analysis, tumor thermotherapy (measurement of deep tissue temperature conductivity), lung ventilator, separation equipment.
Background technology: at present, the core body of the thermistor of China (NTC) medical energy converter adopts silver-colored plane electrode.There is following three aspects: defect in silver plane electrode sensor: 1. silver is to burn by two electrode surfaces of resistive element.Silver point is very low, 961 ℃ of fine silver. and argent directly scorification, on the resistive element surface, but, after being made into silver slurry, is burning till below 800 ℃.The silver electrode surface layer is silver, and there is one deck transition bed centre, the composition of containing metal silver and thermistor oxide in transition bed, and this layer material time to time change, until the silver-colored also compound of Cheng Yin in surface.So unstable.2. silver-colored plane electrode sensor bulk is large, and thermal time constant is large, sensitivity is low, resolution is low, does not meet the medical energy converter requirement.3. silver-colored plane electrode medical energy converter core body is that organic material is sealed, and has also affected the stability of sensor.
The objective of the invention is: provide platinum electrode glass capsulation thermistor (NTC) microballon medical energy converter, to eliminate the current above-mentioned shortcoming that is adopted technology.In the present invention, an example of Medical temperature measuring sensor is: when heart is performed the operation, need to carry out extracorporal circulatory system, systemic blood is by cardiopulmonary bypass unit blood supply oxygen supply.Now cardiac blood oxygen cycle is affected.Take low temperature method to carry out cardioprotection metabolism function.Only according to best temperature curve, control heart and whole body temperature variation, just can obtain the success of operation, otherwise will stay the sequelae that weight does not wait, even dead person to the patient.Adopt a set of installation of sensors in bladder, to monitor the body cavity temperature, one is enclosed within monitoring of cardiac temperature in oesophagus.Operation to the sensor technology parameter request is: 1. thermal time constant is less than 10 seconds; 2. calibration characteristics meets following table, and each calibration point deviation is no more than 0.1 ℃.
| T(℃) |
R(Ω) |
T(℃) |
R(Ω) |
T(℃) |
R(Ω) |
T(℃) |
R(Ω) |
T(℃) |
R(Ω) |
| 14 |
3711 |
15 |
3541 |
16 |
3380 |
17 |
3227 |
18 |
3082 |
| 19 |
2944.6 |
20 |
2814 |
21 |
2689.8 |
22 |
2572 |
23 |
2460 |
| 24 |
2353.3 |
25 |
2252 |
26 |
2155.6 |
27 |
2064 |
28 |
1977 |
| 29 |
1893.5 |
30 |
1814 |
31 |
1738.9 |
32 |
1667 |
33 |
1599 |
| 34 |
1533.3 |
35 |
1471 |
36 |
1411.6 |
37 |
1355 |
38 |
1301 |
Measured medium can only be liquid (liquid in urine or oesophagus), and the detection diameter of sensor is less than 1.4 millimeters simultaneously, and thermal time constant just can be less than 10 seconds.Traditional sensors can not be arranged in bladder, be inserted in the anus chamber, and diameter is large, and thermal time constant is larger.Traditional medical temperature sensor can not adapt to medical requirement far away.The invention provides a kind of platinum electrode glass capsulation thermistor (NTC) microballon Medical temperature measuring sensor, met operation to the sensor technology parameter request.This sensor is by the check at medicine equipment quality supervision center, national Bureau of Drugs Supervision Guangzhou, and the acquisition certificate of competency.At present, medically from the Thermoanalytic sensor sensor, be in the technological gap state in China.In the ordinary course of things, only have diameter<0.5mm, material constant>3800 from thermal sensor, analysis precision just can reach the PPM level.Implement the present invention, having manufactured a kind of stainless-steel tube, to make platinum electrode glass capsulation thermistor (NTC) microballon of sheath medical from thermal sensor, and the measurement of deep tissue temperature conductivity during for tumor thermotherapy, met medical requirement.
Summary of the invention: the 1. stability problem that solves medical energy converter.2. solve the size sensor problem, the basic function of medical energy converter is implemented.In order to improve the stability of sensor, this patent has been invented platinum electrode and sensor sensing core glass Sealing Technology.A. platinum electrode.The platinum fusing point is 1772 ℃, and after 1300 ℃ of once-firings of electrode and resistive element, the platinum filament lattice is constant.Sensor has good stability and reliability.B. sensor core glass capsulation technology.When glass capsulation burnt till, glass was penetrated into the core body internal layer, had driven away the core body residual gas, had filled up gas hole defect, had completely cut off the solid solution phase of semiconductor material and contacting of nature gas phase.Interior layer depth is the 10-20 micron; The outer glassy layer thickness of core body is the 3-15 micron.Changed the method that traditional sensors is directly sealed with organic material.Glass capsulation had both been driven away the core body residual gas, had filled up gas hole defect, had avoided again the destruction of the elements such as the H in the organic material, C, O to the sensor core crystal structure.Therefore sensor stability is improved.Structure and size are determining that can the basic function of sensor be implemented.Medical energy converter requires small size.Size is less, and thermal time constant is just less.Relevant from the resolution of thermal sensor and material constant, electrical current (direct current continuous current) size, also relevant with dissipation factor, size is less, and dissipation factor is less, and resolution is higher.For example: when sensor detection diameter was 0.127 millimeter, thermal time constant was 0.12 second in dead air, in hydrostatic, be 5 milliseconds; Dissipation constant (25 ℃ of .mw/ ℃ of@) is 0.045 in dead air, in hydrostatic, be 0.23.When sensor detection diameter was 1.27 millimeters, thermal time constant was 6.3 seconds in dead air, in hydrostatic, be 180 milliseconds; Dissipation constant (25 ℃ of .mw/ ℃ of@) is 0.45 in dead air, in hydrostatic, be 2.3.Sensor is surveyed diameter and is differed 10 times, and thermal time constant differs 36 times (in water).When water dissipates the power of sensor 2.3mw/ ℃, can make lower the temperature 1 ℃, little person of the large person of diameter lower the temperature 10 ℃, apparent resolution has improved 10 times.Platinum electrode and flass Sealing Technology not only make sensor stability greatly improve, and also make size sensor be reduced to very little degree simultaneously.Electrode becomes the platinum filament shape by traditional flat shape, reduces to platinum filament minimum diameter 0.005mm by plane minimum widith 0.5mm.
Accompanying drawing explanation and embodiment: in appended figure, with nonrestrictive form for example, embodiments of the invention are described.In all accompanying drawings:
Fig. 1 is the constructed profile of sensor core.This figure is the sectional view dissectd along symmetrical plane, so do not mark the symbol of profile position and direction.Wherein 1 mode with signal means glass seal layer; 2 mean platinum electrode; 3 mean the sensor sensing core body.Fig. 1 means: sensor core is comprised of platinum electrode, sensor sensing core body and glass seal layer.
Fig. 2 is the schematic diagram of a kind of platinum electrode glass capsulation thermistor (NTC) microballon Medical temperature measuring sensor.Left figure means the position of installation of sensors in human body in the mode of signal; Right figure is the enlarged drawing of the schematic sectional view of sensor major part, and this figure is the cut-open view dissectd along symmetrical plane, so do not mark the symbol of analysing and observe position and direction.Wherein 1 means that sensor core is arranged on the pharyngeal position of human nasal; 2 mean the position of human heart; 3 mean that sensor core is arranged on the position in the human body oesophagus; 4 mean human bladder's position; 5 mean that sensor core is arranged on the position in bladder; 6 mean the entrance of human body liquid flow sensor; 7 mean the position of sensor core in the tube wall of sensor silicone rubber tube; 8 mean the human body liquid in silicone rubber tube.
Fig. 3 is the medical constructed profile from Thermoanalytic sensor of a kind of platinum electrode glass capsulation thermistor (NTC) microballon, and this figure is the sectional view dissectd along symmetrical plane, so do not mark the symbol of profile position and direction.Wherein 1 means sensor core; 2 mean pore; 3 mean glass-encapsulated; 4 mean air gap; 5 mean stainless-steel tube; 6 mean the platinum electrode extended line; 7 mean silicone rubber for sealing; 8 mean the conducting wire be connected with instrument.
