US3721226A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hot box for asphalt
Assignee: Howe Baker Engineers LLC
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Filing: 1971-08-30
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Granted: 1973-03-20
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Expires: 1991-08-30
Abstract
Abstract A hot box for maintaining asphalt at elevated temperatures including a closed and insulated container, a service apron, a heat exchanger for heating the container, a burner capable of producing high velocity hot gases for driving a mixture of hot gases and air through the heat exchanger and a temperature control system.
Inventors
- 👤 H Childree
- 👤 S Trawick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:46
CPC Classifications
E; E01; E01C; E01C19/00; E01C19/02; E01C19/10; E01C23/00; E01C23/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
176 words
A hot box for maintaining asphalt at elevated temperatures comprising, a container having top, bottom and side walls defining a holding chamber for asphalt, burner means generating high velocity hot gases, and a heat exchanger between the burner means and the container, said heat exchanger including side walls contiguous with and extending down from the side walls of said container and a bottom wall coacting with the side walls and the bottom wall of the container to define a chamber, a firing tube extending centrally into the heat exchange chamber separating same into two heat exchange compartments, said firing tube having an inlet port and a pair of outlet ports, one outlet port for each compartment, said burner means being arranged at the inlet port to discharge its hot gases therein and to induce air into the firing tube and drive a mixture of air and gases through the heat exchanger, baffle means in each compartment defining a continuously reversing gas flow path, and discharge ports in the compartment side walls to discharge the gases therefrom.
Claim 2
Dependent Claim
176 words
A hot box for maintaining asphalt at elevated temperatures comprising, a container having top, bottom and side walls defining a holding chamber for asphalt, burner means generating high velocity hot gases, and a heat exchanger between the burner means and the container, said heat exchanger including side walls contiguous with and extending down from the side walls of said container and a bottom wall coacting with the side walls and the bottom wall of the container to define a chamber, a firing tube extending centrally into the heat exchange chamber separating same into two heat exchange compartments, said firing tube having an inlet port and a pair of outlet ports, one outlet port for each compartment, said burner means being arranged at the inlet port to discharge its hot gases therein and to induce air into the firing tube and drive a mixture of air and gases through the heat exchanger, baffle means in each compartment defining a continuously reversing gas flow path, and discharge ports in the compartment side walls to discharge the gases therefrom.
Claim 3
Dependent Claim
25 words
The combination of claim 1, wherein deflector means is provided in the firing tube to split the mixture of air and gases into the compartments.
Claim 4
Dependent Claim
16 words
The combination of claim 1, wherein the container is formed to be essentially airtight and weatherproof.
Claim 5
Dependent Claim
25 words
The combination of claim 1, and a stack connected to the outlet ports to exhaust the mixture of air and combustion gases above the container.
Claim 6
Dependent Claim
30 words
The combination of claim 1, wherein the side walls of the container and heat exchanger are insulated, and the heat exchanger extends under the entire bottom wall of the container.
Claim 7
Dependent Claim
61 words
The combination of claim 1, wherein an adjustable service apron is provided to hold the hot asphalt during an interim period of time after removal from the hot box but before application to a pothole, said service apron being hinged and thus capable of being tilted to allow asphalt to be dropped from it to the road service at adjustable rates.
Claim 8
Dependent Claim
19 words
The combination of claim 6, and temperature sensing means in the stack for controlling the operation of the burner.
Claim 9
Dependent Claim
27 words
The combination of Claim 6, wherein the burner produces hot gases having a temperature of about 2,800*F and a velocity of 200 to 300 feet per second.
Claim 10
Dependent Claim
174 words
An asphalt hot box comprising a container for asphalt defined by top, bottom and side walls, a heat exchanger directly below the container for transferring heat to the asphalt in the container, said heat exchanger including side walls aligned with the side walls of the container, a bottom wall and being open at the top in direct communication to the bottom wall of the container, whereby gases flowing through the heat exchanger scrub the bottom wall of the container, a fire tube extending centrally through the heat exchanger having an inlet port at one end and a pair of outlet ports at the other end and separating the exchanger into two heat exchange compartments, the outlet ports intercommunicating the heat exchange compartments and the fire tube, baffle means in the heat exchange compartments for causing a circuitous flow path for hot gases, exhaust ports for the heat exchange compartments leading to a stack, and means generating and driving a mixture of air and hot gases into said inlet port and through said heat exchanger.
Claim 11
Dependent Claim
174 words
An asphalt hot box comprising a container for asphalt defined by top, bottom and side walls, a heat exchanger directly below the container for transferring heat to the asphalt in the container, said heat exchanger including side walls aligned with the side walls of the container, a bottom wall and being open at the top in direct communication to the bottom wall of the container, whereby gases flowing through the heat exchanger scrub the bottom wall of the container, a fire tube extending centrally through the heat exchanger having an inlet port at one end and a pair of outlet ports at the other end and separating the exchanger into two heat exchange compartments, the outlet ports intercommunicating the heat exchange compartments and the fire tube, baffle means in the heat exchange compartments for causing a circuitous flow path for hot gases, exhaust ports for the heat exchange compartments leading to a stack, and means generating and driving a mixture of air and hot gases into said inlet port and through said heat exchanger.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |