GB782566A - Improvements in and relating to controlled electric heating apparatus - Google Patents
Improvements in and relating to controlled electric heating apparatusInfo
- Publication number
- GB782566A GB782566A GB270554A GB270554A GB782566A GB 782566 A GB782566 A GB 782566A GB 270554 A GB270554 A GB 270554A GB 270554 A GB270554 A GB 270554A GB 782566 A GB782566 A GB 782566A
- Authority
- GB
- United Kingdom
- Prior art keywords
- energization
- transformer
- relay
- contacts
- cylinder
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03D—APPARATUS FOR PROCESSING EXPOSED PHOTOGRAPHIC MATERIALS; ACCESSORIES THEREFOR
- G03D13/00—Processing apparatus or accessories therefor, not covered by groups G11B3/00 - G11B11/00
- G03D13/006—Temperature control of the developer
-
- 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
- G05D23/2451—Details of the regulator
- G05D23/2453—Details of the regulator using discharge tubes
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Electronic Switches (AREA)
- Control Of Temperature (AREA)
- Control Of Resistance Heating (AREA)
Abstract
782,566. Automatic temperature control systems. NATIONAL RESEARCH DEVELOP MENT CORPORATION. Jan. 27, 1955 [Jan. 29, 1954], No. 2705/54. Class 38 (4). To maintain constant the temperature of a metal cylinder T2 which forms the closed secondary of a transformer T supplied from an A.C. source, contacts A1 of a relay A are opened to de-energize transformer T whenever the current in a resistor R1 falls below a predetermined value. This current is representative of cylin. der temperature since the resistance of the cylinder material increases with temperature, and controls relay A through valves V1 and V2. Contacts A2 of relay A introduce a condenser C2 to change the bias of valve V2 temporarily to ensure that each de-energization of transformer T persists for a predetermined minimum period. Contacts A3 of relay A reduce the bias of valve V1 when the voltage across resistor R1 disappears on de-energization of transformer T. In a modification, the minimum period of de-energization is made to vary inversely with the period of energization by arranging condenser C2 to be slowly charging during the energization period. Cylinder T2 may be a drying cylinder in photographic film recording and developing apparatus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB270554A GB782566A (en) | 1954-01-29 | 1954-01-29 | Improvements in and relating to controlled electric heating apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB270554A GB782566A (en) | 1954-01-29 | 1954-01-29 | Improvements in and relating to controlled electric heating apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB782566A true GB782566A (en) | 1957-09-11 |
Family
ID=9744345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB270554A Expired GB782566A (en) | 1954-01-29 | 1954-01-29 | Improvements in and relating to controlled electric heating apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB782566A (en) |
-
1954
- 1954-01-29 GB GB270554A patent/GB782566A/en not_active Expired
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