Temperature Management in Physiology
Physiological - Biological Temperature Controller TMP-5b
The most important feature of the Physiological - Biological Temperature Controller: it is optimized for microelectrode laboratories, for seriously shielded environments. Its output current is as smooth as the current of a lead battery (with the 12 V FINE DC end-stage, see below). This design fulfils all the special requirements of any sophisticated electrophysiology applications, even in close position to any, high impedance recording electrodes, such as patch clamp setups.
General Description:
We have developed one Physiological - Biological Temperature Controller construction, but it can be built with three different power end-stages, depending on the power requirement of the thermal process under the control. Naturally, only one power end-stage can be installed in a Physiological - Biological Temperature Controller. The price of the Controller does not depend on the kind of the power end-stage installed in it. You should choose the appropriate power end-stage according to the requirements of your actual heating application before palcing an order.
Click on the picture to get it in full size
The Physiological - Biological Temperature Controller is based on an internal microprocessor. The microprocessor on the front plate talks with the user in an intelligent menu system. The firmware in the built-in microprocessor of the Physiological - Biological Temperature Controller realizes a semi-switching control algorithm with a few special fault diagnostic features.
The choice of the power end-stages:
- 12 V FINE DC: max. 36W. It is optimized for microelectrode laboratories, for seriously shielded environments.
Its output current is as smooth as the current of a lead battery. This power end-stage fulfils all the special requirements
of any sophisticated electrophysiology applications, even in close position to any, high impedance recording electrodes,
such as patch clamp setups.
- 24 V pulsing DC: max. 75 W. It is a low voltage, electrically secure version for general purposes.
- 115/230 VAC Huge-power version: up to several kW. It is optimal to control the temperature of great objects.
Technical data:
The controlled temperature range: 0 Centigrade to 120 Centigrade, in 1 Centigrade steps
The resolution of the measurement: 0.1 Centigrade
Histheresis (approximately): 0.3 - 0.5 Centigrade. The actual histheresis depens on the thermal capacity, and the heat drain used on the heated object.
Both internal (built into the heated object), and external temperature sensors can be used. The internal/external sensor selector switch is located at the back side of the Physiological - Biological Temperature Controller.
Display: 4 x 16 characters alphanumeric LCD with bright blue backlight
Programming: three pushbuttons on the front, in menu system
Automatic internal diagnostic algorithm in the software
Flash program memory
Non-volatile EEPROM memory to store the parameters used last time
Temperature sensor (either in internal or external arrangement): DS18S20 from Dallas Semiconductor
Dimensions of the instrument: 290 x 250 x 90 mm
Mains voltage: 100-120V or 220-230V (chosen by an internal selector switch, fixed in the factory)
Power consumption without output load, the Controller only: 80 VA
Weight: 2.8 kg
Special considerations about external temperature sensors:
An external temperature sensor (DS18S20 from Dallas Semiconductor) can be connected to the Physiological - Biological Temperature Controller. There is such a tailored sensor in plastic enclosure, with 1.5 meter BNC cable in our standard product choice. On the back side of the Physiological - Biological Temperature Controller the actually used sensor can be selected with a simple switch. However we do NOT RECOMMEND to use the external temperature sensor. It is possible to eliminate the usage of the external temperature sensor, because in every heated objects of Supertech there are built-in internal temperature sensors. Please, do NOT use the external sensor, except under particular circumstances. There are a few reasons, why it should not be used in most of the applications:
1) The heat capacity, and the thermal time constant of the heated objects are huge. The thermal resistance of the external temperature sensor to the heated object is quite big (in simple words usually there is a bad thermal connection). These statements are true for the technically realized heated objects (as our products), and for the Heating Pad - animal combinations, as well. These effects together result big histheresis (6-8 Centigrade) if you try to use an external sensor. We tested it in many labs, under very different circumstances, but we could not find any hardware and/or software trick to eliminate this effect. As a good solution, we developed a predictive, learning algorithm for the Physiological - Biological Temperature Controller what software runs in the built-in microcontroller. This algorithm uses the internal temperature sensor, what is built into the heated object. This method results a stable, fine regulation of temperature.
2) DS18S20 is one of the most sophisticated temperature sensors in the choice of the semiconductor manufacturers. This is a real top model. It communicates with the host microcontroller in a fully digital way on a 1-wire bus, on standard TTL voltage level. It is a professional sensor, but it generates digital noise, so it should not be placed in a highly sensitive shielded environment, or in a tissue bath close to the working biological target.
3) It is easier to prepare the tissue, or the animal. It is easier to arrange the tissue bath. It is not necessary to keep the rectal, or the bath sensor always clean and sterile.
4) It is not necessary to buy an external temperature sensor.
However if you would like to monitor the core temperature of your animal exactly, please use a Biological Temperature Meter (see its description below).
The complete User Manual of the Physiological - Biological Temperature Controller is available for download.
In our choice there are Small Animal Heating Pads. You shold choose the appropriate size for your actual application (depending on the size of your species).
In all the heating pads there are internal temperature sensors. It is recommended to use them. See the explanation above at the Physiological - Biological Temperature Controller.
The actual choice of the standard size Stainless Steel Heating Pads:
- 115 x 80 mm, 12W, (for mouse)
- 170 x 115 mm, 24W, (for rat)
- 330 x 145 mm, 36W, (for cat, or rabbit)
The temperature difference on the top of the Small Animal Heating Pads, between any two points, is not more than 1 Centigrade, in worst case.
The Small Animal Heating Pads can be washed with wet clothes, with non-agressive solutions. They can be used in humid environment. But it is prohibited to immerse them in water, or try to use them under water!
To use the Small Animal Heating Pads you should buy a Physiological - Biological Temperature Controller, assembled with 12V FINE DC, or 24V DC (depending on the size of the Heating Pad) power end-stage. The standard size of heating pads work on 12V FINE DC.
Stainless Steel Heating Pads:
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The top of these versions of Small Animal Heating Pads are covered with stainless steel plates. It gives a great rigidity, and the opportunity for shielding. On the stainless steel cover there is a metric M4 screw to connect the plate to the central ground point of the lab for shielding purpose. The thickness of the standard heating pads is 12 mm, plus 2 mm the height of the legs.
Custom Size Heating Pads:
Custom size heating pads can be ordered for special applications, as well. The thickness of the custom size heating pads is 12 mm to 20 mm. The thickness depends on the actual measures. The custom size heating pads are multilayer constructions. The top layer is a thin stainless steel plate. Below the stainless steel top plate there is a thick aluminium plate. The third (bottom) layer is a heat insulator plastic plate. The thickness of the aluminium plate (middle layer) can not be decreased too much, because there are electronic circuits inside the aluminium plate. In the heating plates there are active electronic current generators. They are used as heating elements. The current generators are realized by electronic circuits (transistors, diodes, and resistors). The heating pads are manufactured of stainless steel top by default, but if you need it, your heating pad can be realized with anodized black aluminium top.
Biological Temperature Meter BTM-3a
The Biological Temperature Meter is a high accuracy temperature measuring equipment optimized for the temperature range of the living tissues. The resolution of the measurement is 0.1 Centigrade, and the accuracy of the Biological Temperature Meter can be trimmed as good as your temperature reference used for calibration.
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There is an important accessory of Biological Temperature Meter, what always must be used. It is called Pt100 Transducer Box. It is a small equipment in a plastic enclosure. Pt100 Transducer Box should be positioned very close to the Pt100 sensor. The wires of the Pt100 sensor must be minimized as short as possible to keep the level of electric noise (disturbing the temperature measurement) on a low level. The Biological Temperature Meter, and the Pt100 Transducer Box are connected together with a 1.6 meter long wire, wich is not sensitive to disturbing electromagnetic fields. The Pt100 Transducer Box is designed to accept any kind of Pt100 sensors. This feature gives you the possibility to choose that sensor, which optimally fits your experimental environment. The only limitation is, that your sensor must be Pt100 type, but the size, shape, and enclosure of the sensor can be chosen freely.
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There are two internal potmeters located inside the Pt100 Transducer Box. Their names are Gain, and Shift. With these potmeters the error of the temperature measurement can be trimmed to absolute zero. It is always necessary to adjust these potmeters after changing the sensor, because the commercial sensors have got quite high tolerances, and this tolerance can be trimmed to zero. The accuracy of your measurement depends only the correctness of your temperature references what you use to calibrate the Pt100 Transducer Box. The price of the Pt100 Transducer Box is included in the price of the Biological Temperature Meter.
Technical data:
The measured temperature range: - 40 Centigrade to 120 Centigrade
The resolution of the measurement: 0.1 Centigrade
Display: 3.5 characters numeric LCD with backlight
Analog voltage output for PC-based DAQ systems: 0.1 V, or 0.01 V per Centigrade (jumper selectable)
Temperature sensor: Pt100 (the equipment is compatible with any commercially available Pt100 sensors)
Dimensions of the Biological Temperature Meter: 200 x 160 x 75 mm
Dimensions of the Pt100 Transducer Box: 90 x 50 x 25 mm
Mains voltage: 100-120V or 220-230V (chosen by an internal selector switch, fixed in the factory)
Power consumption: 30 VA
Weight: 1.8 kg
Heater for Microscope Stage
The Heater for Microscope Stage is a custom-designed product. We design a special heater pad for you. We design it together with you, according to your special aspects, and requirements. The price is fixed in advance as a unit-price, because the different versions are similar to each other both in their material, and labour costs. In this way we can focus on the professional aspects during the design process, not on the expenses.
Usually the Heaters for Microscope Stages are black, hard-anodized aluminium plates, with 10, or 12 mm in thickness. Sometimes they are dull (unglazed) aluminium products. The aluminium gives a great durability, and rigidity. On the Heaters for Microscope Stages there are usually great holes covered with a thick glass plate, or without glass, depending on the actual requirements.
In the discussion phase we could provide you a schematic design proposal if you would send us a drawing of your stage, plate, and other environmental parts.
An example:
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In the picture you can see a square-shaped example. This model is covered with a thick glass plate. This style of heater must not be used on an inverted microscope.
Other style of heaters could be either round-shaped equipments, as well. The outer diameter, the aperture, the nest of the chamber (if necessary), and the height of the focus plane could be specified by you. The only limitation is, that we have to take care to provide enough space for the heater current sources. We use active electronic current generators as heating elements. The heater current generators are located around the hole on the top, or bottom side of the heater plate.
The temperature difference on the top of the Heater for Microscope Stage, between any two points, is not more than 1 Centigrade, in worst case.
In the Heaters for Microscope Stages there are internal temperature sensors. It is recommended to use them. See the explanation above at the Physiological - Biological Temperature Controller.
To use a Heater for Microscope Stage you should buy a Physiological - Biological Temperature Controller, assembled with 12V FINE DC, or 24V DC power end-stage, depending on the actual design..
Heating Pad for Mouse, and Small Rat Stereotaxic Frame Adaptor
This is a specially designed heating pad to fit to the Mouse, and Small Rat Stereotaxic Frame Adaptor.
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In this heating pad there is an internal temperature sensor, as well. It is recommended to use it. See the explanation above at the Physiological - Biological Temperature Controller.
To use the Heating Pad for Mouse, and Small Rat Stereotaxic Frame Adaptor you should buy a Physiological - Biological Temperature Controller, assembled with 12V FINE DC power end-stage.
Combined Heater for Brain Slice Chamber
This is a specially designed heating equipment to control the temperature of a brain slice chamber, and the incoming solution flow together.
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As you can see in the pictures, the plastic tube can be changed by the user. Before placing an order, the outer diameter of the plastic tube used in your lab should be specified, because we manufacture every piece of the Combined Heater for Brain Slice Chamber especially for the specified tubing to provide the perfect thermal connection.
If you use a
stainless steel chamber, the heat contact to the slice will be perfect. We found
that plexiglas, teflon, or other plastic chambers can not be heated and
controlled perfectly.
In this Combined Heater there is an internal temperature sensor, as well. It is recommended to use it. See the explanation above at the Physiological - Biological Temperature Controller.
To use the Combined Heater for Brain Slice Chamber you should buy a Physiological - Biological Temperature Controller, assembled with 12V FINE DC power end-stage.
There are new models in our product choice to substitute this Combined Heater for Brain Slice Chamber. These newer alternatives are the In-line Solution Heaters.