ThermaCal Temperature Calibration Products -- Model 20

Model 20 Calibration COOL/HEAT Source
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Model 20 COOL and HEAT Sources in one instrument, with the Universal Jaw^™
The Universal Jaw accepts all diameters up to 0.5 inch (12.7mm) and irregularly-shaped probes such as these, which cannot be tested in a standard metal block. In addition, the Universal Jaw has the three most common size holes: 1/4, 3/16, and 1/8 inch (6.4, 4.8, and 3.2mm) for conventionally-shaped probes or external reference probes.

Five hole block diameters: 1/16, 1/8, 3/16, 1/4, and 3/8 inches (1.6, 3.2, 4.8, 6.4, and 9.5 mm).

The Model 20 is available with either one or two modules. You select the combination of modules: COOL Source only, HEAT Source only, COOL Source and HEAT Source, or two HEAT Sources. Both the COOL and HEAT Sources are available with the Universal Jaw or a "five hole block." The Universal Jaw is the choice for testing a large variety of probes up to temperatures of 500°C (932°F). The "five hole block" is required for testing probes in the 500° to 700°C (932° to 1292°F) range, or if the exact diameters to be tested are known. A dual module system with simultaneous cooling and heating is a significant advantage because temperature sensors are rarely tested at only one temperature. The most common procedure is to test at 0°C (32°F) and at the maximum temperature, thereby characterizing the offset and gain errors. Two HEAT Source systems may also be ordered.

COOL Source and HEAT Source Accuracy ThermaCal's accuracy specifications are based on the Setpoint temperature (not an external reference probe and readout); therefore, it is important that the internal reference RTD be repeatable and stable. The reference probes will repeat to ą0.05°C (0.1°F) after heating to 700°C (1292°F) for a period of one year. This performance is equal to most secondary standard calibration RTDs, and is achieved by mounting the platinum wire in a strain-free manner inside an Inconel sheath. An external reference probe and readout can be employed to further enhance the accuracy

NIST
CALIBRATION TRACEABILITY Satisfies ISO and FDA Thermal Validation requirements ThermaCal Inc. certifies the accuracy of its products by using working standard test equipment that is compared to equipment calibrated yearly at NIST (National Institute of Standards and Technology) and redundant equipment calibrated at an independent lab that maintains standards traceable to NIST. This NIST traceable documentation is provided for each calibration including the actual calibration data.

COOL Source and HEAT Source Uniformity
Refer to Figure 1. The internal reference RTD is centered in relation to the 0.5 inch (12.7mm) hole and the three conventional holes. This, in concert with the high thermal conductivity of the aluminum block, virtually eliminates hole-to-hole temperature non-uniformities. Excellent hole depth uniformity is achieved by proper placement of the heaters and insulation. In addition, the actively heated jaws suppress radiation losses from the main part of the block, producing a highly uniform "oven" in the 0.5 inch (12.7mm) hole. Depth uniformity is important because the resistance of an RTD is proportional to the average temperature over its length. A homogeneous thermocouple requires good uniformity, too, because its junction temperature is influenced by any lead wire gradients.

ThermaCal INC.
30275 Bainbridge Road
Solon, OH 44139
Phone:    440/498-1005
Fax:        440/498-1062
E-mail:   thermacal@ameritech.net

Single Module Ordering Code
	COOL	COOL	HEAT	HEAT
	Universal Jaw	5 Hole Block	Universal Jaw	5 Hole Block
	30°C (22°F)	30°C (22°F)	500°C (932°F)	700°C (1292°F)
20-CUJ	*
20-HUJ			*
20-C		*
20-H				*
Dual Module Ordering Code
20-CUJ-HUJ	*		* (see front cover)
20-HUJ-HUJ			* (2)
20-HUJ-H			*	*
20-C-H		*		*
20-H-H				* (2)