Patent US3736360A successfully refreshed from Google Patents.
US3736360A
Expired / Lapsed
US
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Control system for vacuum furnaces
Assignee: ABB Norden Holding AB
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Filing: 1971-10-27
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Granted: 1973-05-29
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Expires: 1991-10-27
Abstract
Abstract A control system for an electrically heated furnace for sintering powder bodies, especially bodies of hard metal, has a vacuum pump connected to the interior of the furnace chamber by a suction conduit. The furnace includes a plurality of heating elements for different zones, a temperature sensitive instrument for each zone and a controlled measuring instrument for one of the zones which is the master zone. These instruments are connected to a master regulator for the furnace and slave regulators for the individual zones. A throttle valve in the vacuum conduit, or a controlled tap connected to the vacuum conduit, make it possible to keep the pressure in the furnace constant despite the fact that the pump runs at a constant speed. A pressure-sensing member connected to the vacuum conduit is also connected to the regulators for the heating elements.
Inventors
- 👤 C Bergman
- 👤 P Larsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:02
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/10; B22F3/1003; B22F3/1007; C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; G; G05; G05D; G05D16/00; G05D16/20; G05D16/2006; G05D16/2013; G05D16/202; B22F2201/00; B22F2201/20; B22F2203/00; B22F2203/03
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
89 words
Method of controlling a vacuum furnace system comprising a vacuum furnace having an electrical heating element, regulating means between said element and an electric power source controlling the heating effect of said elements, a vacuum pump, and a suction conduit element having a gas flow regulating means therein joining the furnace to the vacuum pump, which method comprises sensing the vacuum in said suction conduit element and controlling said gas flow regulating means in response to variations of such vacuum to maintain the pressure in the furnace substantially constant.
Claim 2
Dependent Claim
89 words
Method of controlling a vacuum furnace system comprising a vacuum furnace having an electrical heating element, regulating means between said element and an electric power source controlling the heating effect of said elements, a vacuum pump, and a suction conduit element having a gas flow regulating means therein joining the furnace to the vacuum pump, which method comprises sensing the vacuum in said suction conduit element and controlling said gas flow regulating means in response to variations of such vacuum to maintain the pressure in the furnace substantially constant.
Claim 3
Dependent Claim
22 words
Method according to claim 1, which comprises controlling the heating effect of the furnace elements in response to variations of said vacuum.
Claim 4
Dependent Claim
43 words
Method according to claim 1, which comprises supplying gas from a gas source to the conduit element between the furnace and the vacuum pump by a gas flow regulating means, said supplying of gas maintaining the vacuum pressure level within the preselected level.
Claim 5
Dependent Claim
26 words
Method according to claim 1, which comprises controlling the heating effect of the furnace elements in response to the setting of the gas flow regulating means.
Claim 6
Dependent Claim
121 words
Vacuum furnace equipment which comprises an electrically heated furnace element, a vacuum pump, a suction conduit element joining the furnace to the vacuum pump, heating means in said furnace, a current source, power control equipment arranged between the current source and the furnace element to regulate the heat supplied to the furnace, which includes a pressure sensing member, which senses the pressure in the furnace or conduit element and includes means to deliver an output signal dependent on the pressure, and a gas flow regulating member, and means connected to said pressure sensing member for setting the flow regulating member in a position in accordance with said pressure dependent signal to maintain the vacuum in said suction conduit element substantially constant.
Claim 7
Dependent Claim
121 words
Vacuum furnace equipment which comprises an electrically heated furnace element, a vacuum pump, a suction conduit element joining the furnace to the vacuum pump, heating means in said furnace, a current source, power control equipment arranged between the current source and the furnace element to regulate the heat supplied to the furnace, which includes a pressure sensing member, which senses the pressure in the furnace or conduit element and includes means to deliver an output signal dependent on the pressure, and a gas flow regulating member, and means connected to said pressure sensing member for setting the flow regulating member in a position in accordance with said pressure dependent signal to maintain the vacuum in said suction conduit element substantially constant.
Claim 8
Dependent Claim
23 words
Vacuum furnace equipment according to claim 5, including means responsive to said pressure sensing member to control the heat supplied to the furnace.
Claim 9
Dependent Claim
52 words
Vacuum furnace equipment according to claim 5, in which said gas flow regulating member comprises a throttling member in the suction conduit, and means setting said throttling member in response to the output signal of said pressure sensing member to maintain the pressure in the suction conduit above a minimum preselected value.
Claim 10
Dependent Claim
48 words
Vacuum furnace equipment according to claim 7, which comprises a unit which senses the setting of the throttling member and includes means to emit an output signal dependent on the setting of said member, which influences the power control equipment regulating the heat effect supplied to the furnace.
Claim 11
Dependent Claim
66 words
Vacuum furnace equipment according to claim 5, which comprises a valve with an adjustable throttling member connected to the suction conduit element between the furnace element and the vacuum pump, and means responsive to the output signal of the pressure sensing member to control said throttling member to supply gas to the suction conduit when the pressure in this conduit falls below a minimum preselected value.
Claim 12
Dependent Claim
48 words
Vacuum furnace equipment according to claim 5, which comprises a unit which senses the setting of the throttling member and includes means to emit an output signal dependent on the setting of said member, which influences the power control equipment regulating the heat effect supplied to the furnace.
References Cited (Backward Citations)
US3291969A
Cited
US3428250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |