GB1461480A - Safety circuit and apparatus incorporating it - Google Patents
Safety circuit and apparatus incorporating itInfo
- Publication number
- GB1461480A GB1461480A GB1312974A GB1312974A GB1461480A GB 1461480 A GB1461480 A GB 1461480A GB 1312974 A GB1312974 A GB 1312974A GB 1312974 A GB1312974 A GB 1312974A GB 1461480 A GB1461480 A GB 1461480A
- Authority
- GB
- United Kingdom
- Prior art keywords
- spray gun
- control circuit
- transistor
- scr
- voltage
- 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
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/003—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for electrostatic apparatus
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/08—Plant for applying liquids or other fluent materials to objects
- B05B5/10—Arrangements for supplying power, e.g. charging power
Landscapes
- Electrostatic Spraying Apparatus (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Nozzles (AREA)
- Protection Of Static Devices (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
1461480 Protective systems GRACO Inc 25 March 1974 [26 March 1973] 13129/74 Heading H2K An electrostatic spray gun protective circuit comprises a resistor connected in series with the spray gun electrode for developing a voltage proportional to the current through the electrode, a control circuit having an input connected to the resistor and an output connected to the high voltage source for the spray gun and which generates a signal when the voltage at its input exceeds a threshold level indicating overload, which signal causes the high voltage source to be switched off, and a time delay circuit and desensitizing means connected to the control circuit to cause the control circuit to respond to the voltage exceeding the threshold level only after a certain time delay after switching on to prevent initial surges from causing the spray gun to be switched off. During the desensitized period the control circuit may be responsive at a different threshold level or switching off of the high voltage source may be prevented. The control circuit comprises transistors 35, 36 and 40 which are switched on when a trigger switch 7 on the spray gun is closed to repeatedly charge capacitor 41 through resistor 46 to cause unijunction transistor 43 to repeatedly fire and send a train of firing pulses to SCR 31 in the supply circuit, thus allowing current to flow to the spray gun. A resistor network 55, 56, 57, 58 is in series with the supply to the spray gun and when excessive current flows the voltage at point 54 on the network exceeds the threshold voltage of unijunction transistor 63 causing it to conduct and pass a positive signal to SCR 59 which causes SCR 60 to fire in turn and cut off transistor 40 which cuts off the train of pulses to SCR 31 and thus stops current flowing to the spray gun. On switching on the spray gun an RC timing circuit 49, 50, 51 desensitizes the control circuit by switching on transistor 48 for a timed period to short out resistances 55, 56 and 57. In a second embodiment, Fig. 5, not shown, a resistance in series with transistor 48 establishes a different overload setting during this timed period. In a further embodiment, Fig. 6, not shown, an additional voltage divider resistor network alters the response of the unijunction transistor 63.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00344685A US3809955A (en) | 1973-03-26 | 1973-03-26 | Safety circuit for electrostatic spray gun |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1461480A true GB1461480A (en) | 1977-01-13 |
Family
ID=23351565
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1312974A Expired GB1461480A (en) | 1973-03-26 | 1974-03-25 | Safety circuit and apparatus incorporating it |
Country Status (8)
Country | Link |
---|---|
US (1) | US3809955A (en) |
JP (1) | JPS572392B2 (en) |
CA (1) | CA1001713A (en) |
CH (1) | CH620375A5 (en) |
DE (1) | DE2414524C2 (en) |
FR (1) | FR2223873B1 (en) |
GB (1) | GB1461480A (en) |
IT (1) | IT1007651B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2133942A (en) * | 1983-01-20 | 1984-08-01 | Sharp Kk | Protection for a photocopier corona device |
GB2212679A (en) * | 1987-11-16 | 1989-07-26 | Lai Chin Fay | Overcurrent circuit breaker with time delay |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2620164C2 (en) * | 1976-05-07 | 1978-07-06 | Ionit Anstalt Bernhard Berghaus, Vaduz | Method and device for monitoring high-current glow discharges |
DE3138645A1 (en) * | 1981-09-29 | 1983-04-14 | Dr.Ing.H.C. F. Porsche Ag, 7000 Stuttgart | "ELECTRONIC OVERCURRENT PROTECTION DEVICE" |
DE3300027A1 (en) * | 1983-01-03 | 1984-07-05 | Hermann Behr & Sohn Gmbh & Co, 7121 Ingersheim | Plant for generating a high electrical voltage for paint spray booths |
US4688644A (en) * | 1986-04-14 | 1987-08-25 | Graco Inc. | Ignition and fire suppressor |
DE3709509A1 (en) * | 1987-03-23 | 1988-10-06 | Behr Industrieanlagen | Monitoring system for an electrostatic coating plant |
DE3709510A1 (en) * | 1987-03-23 | 1988-10-06 | Behr Industrieanlagen | METHOD FOR CONTROLLING THE OPERATION OF AN ELECTROSTATIC COATING SYSTEM |
DE69414756T3 (en) * | 1993-04-08 | 2005-03-17 | Nordson Corp., Westlake | Power supply for an electrostatic spray gun |
US5978244A (en) | 1997-10-16 | 1999-11-02 | Illinois Tool Works, Inc. | Programmable logic control system for a HVDC power supply |
US6144570A (en) * | 1997-10-16 | 2000-11-07 | Illinois Tool Works Inc. | Control system for a HVDC power supply |
US20050136733A1 (en) * | 2003-12-22 | 2005-06-23 | Gorrell Brian E. | Remote high voltage splitter block |
DE102015215402A1 (en) * | 2015-08-12 | 2017-02-16 | Gema Switzerland Gmbh | Control circuit for protection against spark discharge |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2509277A (en) * | 1945-04-06 | 1950-05-30 | Ransburg Electro Coating Corp | Control of electrostatic fields |
DE834263C (en) * | 1951-06-29 | 1952-03-17 | Gen Motors Corp | Electrical discharge system and its application to spray painting |
BE715685A (en) * | 1967-07-06 | 1968-10-16 | ||
US3641971A (en) * | 1967-09-01 | 1972-02-15 | Arvid C Walberg | Apparatus for preventing arcing in an electrostatic coating system |
US3725738A (en) * | 1968-12-17 | 1973-04-03 | V Sokolsky | Device for preventing a corona discharge from assuming the form of a spark discharge in electrostatic painting apparatus |
US3544844A (en) * | 1969-07-11 | 1970-12-01 | Hipotronics | Interlocked operation control and overload protective circuit system |
-
1973
- 1973-03-26 US US00344685A patent/US3809955A/en not_active Expired - Lifetime
-
1974
- 1974-03-14 FR FR7408734A patent/FR2223873B1/fr not_active Expired
- 1974-03-18 CH CH373474A patent/CH620375A5/de not_active IP Right Cessation
- 1974-03-20 CA CA195,470A patent/CA1001713A/en not_active Expired
- 1974-03-25 GB GB1312974A patent/GB1461480A/en not_active Expired
- 1974-03-26 JP JP3316374A patent/JPS572392B2/ja not_active Expired
- 1974-03-26 DE DE2414524A patent/DE2414524C2/en not_active Expired
- 1974-04-08 IT IT20843/74A patent/IT1007651B/en active
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2133942A (en) * | 1983-01-20 | 1984-08-01 | Sharp Kk | Protection for a photocopier corona device |
GB2212679A (en) * | 1987-11-16 | 1989-07-26 | Lai Chin Fay | Overcurrent circuit breaker with time delay |
GB2212679B (en) * | 1987-11-16 | 1992-01-15 | Lai Chin Fay | Over current circuit breaker |
Also Published As
Publication number | Publication date |
---|---|
US3809955A (en) | 1974-05-07 |
JPS49128950A (en) | 1974-12-10 |
FR2223873A1 (en) | 1974-10-25 |
DE2414524C2 (en) | 1984-11-29 |
JPS572392B2 (en) | 1982-01-16 |
DE2414524A1 (en) | 1974-10-10 |
CA1001713A (en) | 1976-12-14 |
IT1007651B (en) | 1976-10-30 |
FR2223873B1 (en) | 1981-05-29 |
CH620375A5 (en) | 1980-11-28 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed [section 19, patents act 1949] | ||
PCNP | Patent ceased through non-payment of renewal fee |