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GB2021819A - Temperature control system - Google Patents

Temperature control system

Info

Publication number
GB2021819A
GB2021819A GB7915055A GB7915055A GB2021819A GB 2021819 A GB2021819 A GB 2021819A GB 7915055 A GB7915055 A GB 7915055A GB 7915055 A GB7915055 A GB 7915055A GB 2021819 A GB2021819 A GB 2021819A
Authority
GB
United Kingdom
Prior art keywords
circuit
triac
heater
line voltage
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB7915055A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Applied Biosystems Inc
Original Assignee
Perkin Elmer Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Perkin Elmer Corp filed Critical Perkin Elmer Corp
Publication of GB2021819A publication Critical patent/GB2021819A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
    • G01N25/4806—Details not adapted to a particular type of sample
    • G01N25/4826—Details not adapted to a particular type of sample concerning the heating or cooling arrangements
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1906—Control of temperature characterised by the use of electric means using an analogue comparing device
    • G05D23/1913—Control of temperature characterised by the use of electric means using an analogue comparing device delivering a series of pulses
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Control Of Temperature (AREA)
  • Control Of Resistance Heating (AREA)

Abstract

A temperature control system for a heater surrounding an enclosure and powered by an AC supply, comprises a circuit for generating a constant slope ramp signal having a variable height and period directly related to the value of AC line voltage to compensate for fluctuations in said value. A comparator IC3 (Figure 2) generates a disabling signal whenever the ramp signal equals or exceeds a temperature error signal. For the duration of each disabling signal, a zero-crossing circuit IC4 is prevented from generating control pulses. When the ramp signal is less than the temperature error signal produced by a circuit including a platinum resistance thermometer R15, a control pulse is generated each time the AC line voltage crosses the zero-voltage point; each control pulse switches on a triac TR at the beginning of a half-cycle of AC line voltage, thereby energising a heater R13 connected in series with the triac. The triac trigger circuit is coupled to a zero crossing detector circuit via an optical link including light emitting diode D1 and SCR-PH. The heater may surround an enclosure of a differential thermal analysis instrument. <IMAGE>
GB7915055A 1978-05-10 1979-05-01 Temperature control system Withdrawn GB2021819A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US90469978A 1978-05-10 1978-05-10

Publications (1)

Publication Number Publication Date
GB2021819A true GB2021819A (en) 1979-12-05

Family

ID=25419596

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7915055A Withdrawn GB2021819A (en) 1978-05-10 1979-05-01 Temperature control system

Country Status (3)

Country Link
JP (1) JPS54148979A (en)
DE (1) DE2917885A1 (en)
GB (1) GB2021819A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2207261A (en) * 1987-06-16 1989-01-25 South Of Scotland Electricity Temperature control circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2207261A (en) * 1987-06-16 1989-01-25 South Of Scotland Electricity Temperature control circuit
GB2207261B (en) * 1987-06-16 1992-01-08 South Of Scotland Electricity Temperature control circuit

Also Published As

Publication number Publication date
DE2917885A1 (en) 1979-11-22
JPS54148979A (en) 1979-11-21

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)