US3597850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous vacuum drier
Assignee: National Service Industries Inc
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Filing: 1970-03-11
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Granted: 1971-08-10
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Expires: 1990-03-11
Abstract
Abstract A continuous vacuum drier for removing moisture from solid synthetic resins in granular form prior to manufacturing into finished products. The synthetic resinous material is continuously supplied to the top of a closed drying hopper and removed from the bottom of the hopper. In one embodiment air withdrawn from the top of the hopper is circulated through a heater and is returned to the bottom of the hopper, where it travels upwardly through the synthetic resinous material in the hopper. In a second embodiment, air is withdrawn from the bottom of the hopper and is returned to the top of the hopper, where it travels downwardly through the synthetic resinous material in the hopper. The circulated air and the material in the hopper are heated as they pass grids of pipes which are heated by circulated hot water. In both embodiments, a vacuum pump is connected to reduce the air pressure in the system for increasing the efficiency of the drier and for causing the hopper to automatically fill with material to a predetermined level from a primary feeder hopper. A small amount of dry air may be introduced into the hopper for carrying off evaporated moisture. The dry material is fed by gravity from the bottom of the hopper to a processor.
Inventors
- 👤 John W Jenkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:03
CPC Classifications
B; B29; B29B; B29B13/00; B29B13/06; B29B13/065; B29C; B29C48/00; B29C48/25; B29C48/285; B29C48/287; B29C48/288; F; F26; F26B; F26B17/00; F26B17/12; F26B17/128; F26B21/00; F26B21/20; F26B21/25; B29C48/03
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
19 words
The apparatus of claim 1 including means for heating the air before it is returned back into said hopper.
Claim 2
Dependent Claim
22 words
The apparatus of claim 2 including means on the input side of said blower for filtering the air withdrawn from said hopper.
Claim 3
Dependent Claim
101 words
The apparatus of claim 2 including a feed conduit providing communication from the exterior to the interior of said hopper, said conduit having an end exterior to said hopper for burying in a supply of granular material and an end interior to said hopper, whereby when said exterior end of said feed conduit is buried in a supply of granular material subject to a surface pressure above the subatmospheric pressure on the interior of said hopper, the material flows through said conduit into said hopper as a consequence of the pressure difference between the supply and the interior of said hopper.
Claim 4
Dependent Claim
131 words
Apparatus for holding and drying granular materials, comprising, a closed hopper having a top portion and a bottom portion, means for continuously filling said hopper with granular material, means for removing air from the granular material before it enters said hopper, means for continuously withdrawing the granular material from the bottom of said hopper, control means for regulating the flow of material to said hopper for maintaining a predetermined material level in said hopper, means for withdrawing air from the top of said hopper and for returning the air to the bottom of said hopper, means for heating the air before it is returned to the bottom of said hopper, means for maintaining said hopper at a subatmospheric pressure, and means for bleeding a controlled amount of air into said hopper.
Claim 5
Independent Claim
82 words
A method for continuously drying granular materials said method comprising, charging the material into the top portion of a closed hopper having a top portion and a bottom portion to maintain a predetermined material level and withdrawing dried material from the bottom portion of the hopper, circulating an airstream from the top portion of the hopper and back to the bottom portion of the hopper, heating the circulated airstream, and withdrawing an airstream from the hopper to maintain a subatmospheric pressure therein.
Claim 6
Dependent Claim
23 words
A method for continuously drying granular materials as claimed in claim 6, and including bleeding a controlled amount of air into said hopper.
Claim 7
Dependent Claim
112 words
Apparatus for holding and drying granular materials prior to processing into finished products, comprising, a closed hopper having a bottom portion, means for filling said hopper with granular material to a predetermined level, means for withdrawing the granular material from the bottom of said hopper, an air circulating blower having an input and an output, both operatively connected to said hopper, one above and one below said predetermined level whereby air withdrawn from said hopper by said blower is returned to said hopper and is circulated through the material held in said hopper, and means for withdrawing air from said hopper to maintain the interior of said hopper at a subatmospheric pressure.
Claim 8
Dependent Claim
34 words
Apparatus for holding and drying granular materials, as defined in claim 8, and including means for heating the material in said hopper and for heating the air as it is circulated through said hopper.
Claim 9
Dependent Claim
40 words
Apparatus for holding and drying granular materials, as defined in claim 9, wherein said heating means comprises at least one pipe extending through the material in said hopper and means for circulating a heated heat transfer fluid through said pipe.
Claim 10
Dependent Claim
38 words
Apparatus for holding and drying granular materials, as defined in claim 10, wherein said pipe is shaped and positioned such that the material passes within 4 inches of said pipe as the material moves downwardly through said hopper.
Claim 11
Independent Claim
87 words
A method for continuously drying granular materials, said method comprising, charging the material into the top portion of a closed hopper having a top portion and a bottom portion to maintain a predetermined material level and withdrawing dried material from the bottom portion of the hopper, circulating an airstream from the bottom portion of the hopper and back to the top portion of the hopper, heating the material as it passes through the hopper, anD withdrawing an airstream from the hopper to maintain a subatmospheric pressure therein.
Claim 12
Dependent Claim
23 words
A method for continuously drying granular materials, as claimed in claim 12, and including bleeding a controlled amount of air into said hopper.
Claim 13
Dependent Claim
115 words
Apparatus for holding and drying synthetic resinous materials prior to processing into finished products, comprising, a closed hopper having a bottom portion, means for maintaining said hopper filled to a predetermined level with synthetic resinous material, means for withdrawing the synthetic resinous material from the bottom of said hopper, an air-circulating blower having an input and an output, both operatively connected to said hopper, one above and one below said predetermined level whereby air withdrawn from said hopper by said blower is returned to said hopper and is circulated through the material held in said hopper, and means for withdrawing air from said hopper to maintain the interior of said hopper at a subatmospheric pressure.
Claim 14
Dependent Claim
25 words
Apparatus for holding and drying synthetic resinous materials, as defined in claim 14, and including means for heating the synthetic resinous material in said hopper.
Claim 15
Dependent Claim
52 words
Apparatus for holding and drying synthetic resinous materials, as defined in claim 14, wherein said means for withdrawing material from said hopper includes an extruder for processing the synthetic resinous material held in said hopper and means providing a closed operative connection from the bottom portion of said hopper to said extruder.
Claim 16
Dependent Claim
53 words
Apparatus for holding and drying synthetic resinous materials, as defined in claim 14, wherein said means for withdrawing material from said hopper includes injection-molding apparatus for processing the synthetic resinous material held in said hopper and means providing a closed operative connection from the bottom portion of said hopper to said injection-molding apparatus.
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) | 1974-08-09 | 1975-02-08 | 1975-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-09 | 1979-02-08 | 1979-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-09 | 1983-02-08 | 1983-08-10 | $7700.00 | Window Closed / Lapsed |