US4668390A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High efficiency deep fat fryer
Assignee: Thermo Fisher Scientific Inc
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Filing: 1985-10-28
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Granted: 1987-05-26
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Expires: 2005-10-28
Abstract
Abstract Disclosed is a high efficiency deep fat fryer from whose fry tank fat is continuously withdrawn for heating and filtration. A pump circulates part of this fat through a helical- or serpentine-shaped finned-tube heat exchanger positioned between a gas-fired burner and the bottom of the fry tank. The remaining portion of fat is directed through a filter located in the bottom zone of the fry tank. The fryer includes a control system with sensors such as pressure switches for preventing damage to the fat at low flow rates and devices for expelling moisture trapped in the pump. The filter has an element of material such as carbon-impregnated cloth which may be quickly replaced without draining fat from the tank.
Inventors
- 👤 James R. Hurley
- 👤 Robert A. Panora
- 👤 Edward F. Searight
- 👤 Kailash C. Shukla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:03
CPC Classifications
A; A47; A47J; A47J37/00; A47J37/12; A47J37/1233; Y; Y10; Y10S; Y10S210/00; Y10S210/08
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
243 words
In a deep fat fryer including a tank for holding cooking fat and having means defining a fry zone and means defining a bottom zone below said fry zone, a filter for filtering the fat, a heat exchanger external to the tank, means for delivering heat to said heat exchanger, and means for circulating the fat through the heat exchanger and thereafter returning the fat to said tank, the improvement wherein said filter includes a means defining an inlet for receiving fat to be filtered a means defining an outlet for returning fat to said tank, and said means for circulating the fat comprises (a) pump means for removing fat from said tank and circulating fat for return to said tank, (b) a first return loop having an inlet end connected to said pump means and an outlet end connected to said tank, said heat exchanger being positioned in said first return loop between said inlet end and said outlet end and being operable to pass fat therethrough, and (c) a second return loop having an inlet end connected to said pump means and an outlet end connected to the inlet of said filter; said loops and said pump means operable to pass a first portion of the flow of fat from said pump means through said filter and to pass a second portion of the flow of fat from said pump means through the heat exchanger and then back to said tank.
Claim 2
Dependent Claim
243 words
In a deep fat fryer including a tank for holding cooking fat and having means defining a fry zone and means defining a bottom zone below said fry zone, a filter for filtering the fat, a heat exchanger external to the tank, means for delivering heat to said heat exchanger, and means for circulating the fat through the heat exchanger and thereafter returning the fat to said tank, the improvement wherein said filter includes a means defining an inlet for receiving fat to be filtered a means defining an outlet for returning fat to said tank, and said means for circulating the fat comprises (a) pump means for removing fat from said tank and circulating fat for return to said tank, (b) a first return loop having an inlet end connected to said pump means and an outlet end connected to said tank, said heat exchanger being positioned in said first return loop between said inlet end and said outlet end and being operable to pass fat therethrough, and (c) a second return loop having an inlet end connected to said pump means and an outlet end connected to the inlet of said filter; said loops and said pump means operable to pass a first portion of the flow of fat from said pump means through said filter and to pass a second portion of the flow of fat from said pump means through the heat exchanger and then back to said tank.
Claim 3
Dependent Claim
57 words
A deep fat fryer as in claim 1 wherein the said first return loop includes a pipe connected to the upper central portion of a wall of said tank, said pipe adapted to discharge fat into the fry zone in a manner to produce turbulent jetting action of fat in contact with foods held within said tank.
Claim 4
Dependent Claim
34 words
A deep fat fryer as in claim 1 wherein said pump means comprises a pump having an inlet connected to said tank and an outlet connected to the inlet ends of said return loops.
Claim 5
Dependent Claim
32 words
A deep fat fryer as in claim 3 further including means for inhibiting entry of moisture from the tank into the inlet of said pump as fat is withdrawn from the tank.
Claim 6
Dependent Claim
35 words
A deep fat fryer as in claim 4 wherein said means for inhibiting entry of moisture includes a perforated tray of fine mesh positioned between said fry zone and said bottom zone of the tank.
Claim 7
Dependent Claim
79 words
A deep fat fryer as in claim 4 wherein said means for inhibiting entry of moisture includes a standpipe connected to the inlet side of said pump and extending upward through a means defining an opening in the bottom of the tank, and a baffle assembly substantially enclosing the portion of the standpipe within the tank, said baffle assembly having at least one opening to admit fat into the interior of said baffle assembly for entry into said standpipe.
Claim 8
Dependent Claim
28 words
A deep fat fryer as in claim 1 wherein said means for delivering heat to said heat exchanger comprises a gas-fired lanced-port burner operable at essentially atmospheric pressure.
Claim 9
Dependent Claim
78 words
A deep fat fryer as in claim 7 wherein said heat exchanger comprises a helically coiled tube positioned between said burner and the bottom of said tank, said tube having an axis substantially normal to the plane of the bottom of said tank and a radius measured from said axis which varies continuously with distance along said axis from a first radius at the inlet of said tube to a second radius at the outlet of said tube.
Claim 10
Dependent Claim
18 words
A deep fat fryer as in claim 8 wherein said second radius is smaller than said first radius.
Claim 11
Dependent Claim
30 words
A deep fat dryer as in claim 7 further including control means for controlling operation of said burner in response to the flow rate of fat through said pump means.
Claim 12
Dependent Claim
82 words
A deep fat fryer as in claim 10 wherein said control means includes a gas valve for regulating the flow of gas to said burner and a pair of pressure switches, each of said switches operable to sense pressures at the outlet of said pump means, said switches being electrically connected in series to said gas valve in a manner such that both switches must be closed for said gas valve to be open to permit flow of gas to said burner.
Claim 13
Dependent Claim
16 words
A deep fat fryer as in claim 1 wherein said filter is positioned in said tank.
Claim 14
Dependent Claim
26 words
A deep fat fryer as in claim 1 wherein said means for delivering heat to said heat exchanger comprises a burner mounted below said heat exchanger.
Claim 15
Dependent Claim
131 words
A deep fat fryer comprising: a tank for holding cooking fat, said tank having means defining a fry zone and means defining a bottom zone below said fry zone; a filter positioned in the bottom zone of said tank; pump means external to the tank for withdrawing fat from said tank and circulating fat for return to said tank; first and second return loops arranged in parallel between said pump means and said tank for returning fat to the tank, said first loop including a heat exchanger for permitting heating of fat carried thereby and said second loop having an outlet connected to the inlet of said filter; and a gas-fired burner mounted below said heat exchanger for delivering heat to said heat exchanger and to the bottom of said tank.
Claim 16
Dependent Claim
131 words
A deep fat fryer comprising: a tank for holding cooking fat, said tank having means defining a fry zone and means defining a bottom zone below said fry zone; a filter positioned in the bottom zone of said tank; pump means external to the tank for withdrawing fat from said tank and circulating fat for return to said tank; first and second return loops arranged in parallel between said pump means and said tank for returning fat to the tank, said first loop including a heat exchanger for permitting heating of fat carried thereby and said second loop having an outlet connected to the inlet of said filter; and a gas-fired burner mounted below said heat exchanger for delivering heat to said heat exchanger and to the bottom of said tank.
Claim 17
Dependent Claim
29 words
A deep fat fryer as in claim 14 including control means for controlling operation of said burner in respnse to the flow rate of fat through said pump means.
Claim 18
Dependent Claim
83 words
A deep fat fryer as in claim 14 wherein said heat exchanger comprises a helically coiled tube positioned between said burner and the bottom of said tank, said tube having an axis substantially normal to the plane of the bottom of said tank and a radius measured from said axis which varies continuously with distance along said axis from a first radius at the inlet of said tube to a second radius smaller than said first radius at the outlet of said tube.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-25 | 1990-11-24 | 1991-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-25 | 1994-11-24 | 1995-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-25 | 1998-11-24 | 1999-05-26 | $7700.00 | Window Closed / Lapsed |