TÂonutà Melting Rate Programmer for 7Âûma&-Hoover Melting Point Apparatus

automatically controls temperature rise to comply with U.S.P. specifications

• eliminates subjective operator error

• promotes inter-plant and inter-shift uniformity

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V J For automatically controlling rate of temperature rise in Thomas-Hoover Melting Point Apparatus. Ensures compliance with U.S.P. specifications for melting point determination on pharmaceutical products. Increases accuracy of m.p. determina­tions by eliminating subjective operator error in establishing and maintaining constant melting rate.

Frees analyst for other duties by making it un­necessary for him to remain at the instrument during bath warm-up. Assures inter-shift and inter-plant uniformity in technique and results. Usable with all Thomas-Hoover units now in service.

Specifications Range 0 to 360°C. Heating Rate Options %, 1, 1%, 2, 3, 5 and 10 degrees per minute. Heating Rate Accuracy within 1% of selected rate. Installation. No modification of Thomas-Hoover unit is required. Platinum resistance thermometer probe mounts in standard melting bath unit. Plug-in har­ness completes necessary circuitry; no re-wiring re­quired. Locking clamp secures autotransformer rotor at maximum input position.

Operation. Operator sets program starting point to a few degrees below, and high temperature limit to a few degrees above, the expected melting point. Pro­grammer is switched to isothermal mode, desired heating rate is selected, and power switches are turned on. When bath reaches the selected program start point, the isothermal control maintains this tempera­ture.

The operator, who has been free to perform other duties during the heat-up period, now switches unit to programmed mode, and begins observing sample. The bath temperature increases at the selected rate, as in­dicated by the advancing white pointer.

After recording the melting point the operator may permit the temperature to rise to the temperature preset as high limit, if samples of higher melting point are to be subsequently programmed. Alterna­tively, operator may return programmer to isothermal mode, reset the program start point, and allow the bath to cool to this point for repetition of the deter­mination. Rate of temperature rise may be changed, stopped, or started, at any time during operation. 6406-R10. Programmer, as described. For 115 volts, 60 cycles, a.c. Without Melting Point Apparatus . . 800.00 6406-R20. Ditto, for 115 volts, 50 cycles, a.c 800.00

Bulletin 155 sent upon request.

7Âotnaû. ARTHUR H. THOMAS COMPANY Scientific Apparatus and Reagents

110 A . ANALYTICAL CHEMISTRY, VOL. 42, NO. 12, OCTOBER 1970

Circle Ne. 145 ce Readers' Service Card

VINE STREET AT 3RD · P.O. BOX 7 7 9 · PHILADELPHIA, PA. 19105, U.S.A.