US3695597A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Furnace for heat treating objects under pressure
Assignee: ABB Norden Holding AB
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Filing: 1970-09-01
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Granted: 1972-10-03
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Expires: 1990-09-01
Abstract
Abstract In manufacturing sintered bodies, a compacted charge of powder forming a billet is enclosed in a sealed casing of soft metal such as steel from which the air has been evacuated. The casing and powder are subjected to pressure at high temperature in a furnace chamber to sinter the powder. Before its introduction into the chamber, the charge is heated outside the furnace to treating temperature. The charge is inserted from below into the furnace, after which the bottom opening of the furnace is closed and pressure medium is introduced. The furnace has an insulating sheath within the furnace chamber depending from the top of the chamber and terminating near its bottom. The material of the casing is so chosen that there will be substantially no interchange of material especially of carbon, with the material of the compacted billet.
Inventors
- 👤 Hans Lundstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:02
CPC Classifications
B; B30; B30B; B30B11/00; B30B11/001; B30B11/002; B22; B22F; B22F3/00; B22F3/12; B22F3/14; B22F3/15; C; C03; C03B; C03B19/00; C03B19/06; C03B29/00; C03B29/02; C04; C04B; C04B33/00; C04B33/32; C04B33/326
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
235 words
Furnace for use in a method of manufacturing sintered bodies which comprises enclosing a charge of powder in a casing, evacuating air from the casing, sealing the casing, inserting the casing and its contents into a furnace having a furnace chamber which is enclosed in a pressure chamber, subjecting the sealed casing to high pressure at high temperature so that the powder sinters, the evacuated casing being heated outside the furnace, inserted from below into the furnace chamber which is heated to sintering temperature and located inside the pressure chamber through a charging opening, the pressure chamber being closed and a pressure medium being pumped into the pressure chamber while setting the pressure and temperature for sintering, for a predetermined length of time, which furnace comprises a cylindrical pressure chamber including a high pressure cylinder with a furnace chamber therein, upper and lower end closures projecting into said cylinder, insulation in the pressure chamber between said furnace chamber and the walls of the pressure chamber, which insulation comprises an insulating sheath with insulating lid and bottom, and in which the upper end closure of the pressure chamber is permanently secured in the high pressure cylinder, the insulating sheath and the insulating lid are suspended in the upper end closure and the lower end closure supports the insulating bottom and the charge and can be raised and lowered while the furnace is being charged from below.
Claim 2
Dependent Claim
235 words
Furnace for use in a method of manufacturing sintered bodies which comprises enclosing a charge of powder in a casing, evacuating air from the casing, sealing the casing, inserting the casing and its contents into a furnace having a furnace chamber which is enclosed in a pressure chamber, subjecting the sealed casing to high pressure at high temperature so that the powder sinters, the evacuated casing being heated outside the furnace, inserted from below into the furnace chamber which is heated to sintering temperature and located inside the pressure chamber through a charging opening, the pressure chamber being closed and a pressure medium being pumped into the pressure chamber while setting the pressure and temperature for sintering, for a predetermined length of time, which furnace comprises a cylindrical pressure chamber including a high pressure cylinder with a furnace chamber therein, upper and lower end closures projecting into said cylinder, insulation in the pressure chamber between said furnace chamber and the walls of the pressure chamber, which insulation comprises an insulating sheath with insulating lid and bottom, and in which the upper end closure of the pressure chamber is permanently secured in the high pressure cylinder, the insulating sheath and the insulating lid are suspended in the upper end closure and the lower end closure supports the insulating bottom and the charge and can be raised and lowered while the furnace is being charged from below.
Claim 3
Dependent Claim
20 words
Furnace according to claim 1, in which resistance elements to heat the furnace are suspended in the upper end closure.
Claim 4
Dependent Claim
21 words
Furnace according to claim 1 in which the insulating sheath is connected in a gas-tight manner to the upper end closure.
Claim 5
Dependent Claim
35 words
Furnace according to claim 3, in which there is a space between the insulating lid and the upper end closure and the furnace chamber through a pressure-equalizing opening connecting said space to the furnace chamber.
Claim 6
Dependent Claim
28 words
Furnace according to claim 1, comprising a tube suspended in the insulating lid and surrounding the furnace and resistance elements to heat the furnace supported by said tube.
Claim 7
Dependent Claim
19 words
Furnace according to claim 5, in which the resistance elements are arranged on the outside of the supporting tube.
Claim 8
Dependent Claim
27 words
Furnace according to claim 6, comprising vertical rails with horizontal slots facing the tube, the resistance elements being supported in said rails and passing through said slots.
Claim 9
Dependent Claim
19 words
Furnace according to claim 7, in which the vertical rails are carried by the tube carrying the resistance elements.
Claim 10
Dependent Claim
43 words
Furnace according to claim 6, in which the tube carrying the resistance elements is suspended in the insulating lid by means of said rails and at a distance from the lid so that openings are formed between lid and tube between the rails.
Claim 11
Dependent Claim
19 words
Furnace according to claim 5, in which there are gas-tight bushings in the insulating lid for the resistance elements.
Claim 12
Dependent Claim
18 words
Furnace according to claim 1, including supply conduits for said resistance elements passing through the upper end closure.
Claim 13
Dependent Claim
44 words
Furnace according to claim 1, in which the lower end closure comprises a ring-shaped part permanently suspended in the high pressure cylinder and a lid inside this ring-shaped part which can be raised and lowered and which supports the insulating bottom and the charge.
Claim 14
Dependent Claim
36 words
Furnace according to claim 12, in which the ring-shaped part of the end closure supports an insulating ring which projects into the insulating sheath so that between this and the ring a narrow gap is formed.
Claim 15
Dependent Claim
45 words
Furnace according to claim 12, in which in the ring-shaped part of the end closure is arranged a ring-shaped axially lowerable radiation protection which, when the lid is lowered, is lowered and protects the sealing surface in the ring-shaped part from radiation from the charge.
References Cited (Backward Citations)
US3628779A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |