US3796412A
Expired / Lapsed
US
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Apparatus and method for controlling moisture content of granular materials
Assignee: Georg Fischer AG
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Filing: 1972-10-03
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Granted: 1974-03-12
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Expires: 1992-10-03
Abstract
Abstract Granular material is fed to a mixing drum, and a plurality of controllable nozzles are aligned with the interior of the mixing drum for selectively introducing water into the mixing drum. A control circuit is responsive to at least one of the power input and the driving torque of the drive means for the mixing drum, to control a main control valve which controls the total quantity of water per unit time delivered into the interior of the mixing drum. The control circuit may also be responsive to the temperature of the granular material fed to the mixing drum for further control of the main control valve. A pressure control device is provided between the main control valve and the nozzles to maintain the water pressure between predetermined boundary values so that water is delivered to said drum with an approximately constant droplet size.
Inventors
- 👤 E Maurer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:31
CPC Classifications
B; B22; B22C; B22C5/00; B22C5/08
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
226 words
Apparatus for controlling the moisture content of granular material such as molding sand, comprising: a mixing drum for processing granular material; means for feeding granular material to the drum; a plurality of controllable nozzle means aligned with the interior of said mixing drum for selectively introducing water into said mixing drum; drive means for driving said mixing drum; a main control valve means for controlling the total quantity of water per unit time delivered into the interior of said mixing drum; a control circuit coupled to and controlling said main control valve means, said control circuit including electrical measurement means for measuring at least one of the power input and the driving torque of said drive means for said mixing drum, and means for controlling said main valve means to control the feed of water to the mixing drum as a function of at least one of said power input and driving torque; and a pressure control device arranged between said main control valve means and said nozzle means and being operable for measuring the water pressure upstream of said nozzle means and for maintaining said water pressure between predetermined boundary values, such that upon the water pressure exceeding a predetermined maximum value a nozzle means is switched in, and upon the water pressure dropping below the predetermined minimum value a nozzle means is switched out.
Claim 2
Dependent Claim
226 words
Apparatus for controlling the moisture content of granular material such as molding sand, comprising: a mixing drum for processing granular material; means for feeding granular material to the drum; a plurality of controllable nozzle means aligned with the interior of said mixing drum for selectively introducing water into said mixing drum; drive means for driving said mixing drum; a main control valve means for controlling the total quantity of water per unit time delivered into the interior of said mixing drum; a control circuit coupled to and controlling said main control valve means, said control circuit including electrical measurement means for measuring at least one of the power input and the driving torque of said drive means for said mixing drum, and means for controlling said main valve means to control the feed of water to the mixing drum as a function of at least one of said power input and driving torque; and a pressure control device arranged between said main control valve means and said nozzle means and being operable for measuring the water pressure upstream of said nozzle means and for maintaining said water pressure between predetermined boundary values, such that upon the water pressure exceeding a predetermined maximum value a nozzle means is switched in, and upon the water pressure dropping below the predetermined minimum value a nozzle means is switched out.
Claim 3
Dependent Claim
55 words
Apparatus according to claim 1, wherein said control circuit includes a temperature measuring device for measuring the temperature of the granular material being fed to the mixing drum, and means for operating said main control valve means as a function of both said temperature and at least one of said power input and driving torque.
Claim 4
Dependent Claim
108 words
Apparatus according to claim 2, wherein said pressure control device includes a riser conduit arranged between said nozzle means and said main control valve means, and an upper level switch and a lower level switch operably coupled to said riser conduit to sense the water level in said riser conduit and switching means coupling said upper and lower level switches to individual nozzle means such that the water level in said riser conduit reaches said upper level switch at least one of said nozzle means is switched in and when the water level reaches said lower level switch at least one of said nozzle means is switched out.
Claim 5
Dependent Claim
109 words
Apparatus according to claim 1, wherein said pressure control device includes a riser conduit arranged between said nozzle means and said main control valve means, and an upper level switch and a lower level switch operably coupled to said riser conduit to sense the water level in said riser conduit and switching means coupling said upper and lower level switches to individual nozzle means such that when the water level in said riser conduit reaches said upper level switch at least one of said nozzle means is switched in and when the water level reaches said lower level switch at least one of said nozzle means is switched out.
Claim 6
Dependent Claim
23 words
Apparatus according to claim 4, wherein said nozzle means each include a control valve operatively connected to said upper and lower level switches.
Claim 7
Dependent Claim
61 words
Apparatus according to claim 4, wherein said switching means includes a motor, the rotation of which is controlled by said upper and lower level switches, and a plurality of control switches respectively coupled to said nozzle means and operably connected to said motor to selectively switch in or out said nozzle means as a function of the rotation of said motor.
Claim 8
Dependent Claim
14 words
Apparatus according to claim 1, wherein said nozzle means each include a control valve.
Claim 9
Dependent Claim
20 words
Apparatus according to claim 1, wherein said control circuit controls said control valve as a function of the power input.
Claim 10
Dependent Claim
20 words
Apparatus according to claim 1, wherein said control circuit controls said control valve as a function of the driving torque.
Claim 11
Dependent Claim
26 words
Apparatus according to claim 1, wherein said mixer maintains a substantially constant quantity of said granular material therein independent of the supply of granular material thereto.
Claim 12
Dependent Claim
21 words
Apparatus according to claim 1, wherein said feed means feeds said granular material to said drum at a substantially constant rate.
Claim 13
Dependent Claim
31 words
Apparatus according to claim 1, wherein said pressure control device maintains said water pressure such that said nozzles deliveR said water to said drum with an approximately constant predetermined droplet size.
Claim 14
Independent Claim
133 words
A method for controlling the moisture content of granular material such as moulding sand, comprising: feeding granular material to a mixing drum; driving said mixing drum; measuring at least one of the power input and driving torque of the driving means for said mixing drum; controlling the feed of water to a plurality of nozzles which are aligned with the interior of the mixing drum for introducing water into the mixing drum, as a function of at least one of said power input and driving torque; and measuring the water pressure upstream of said nozzles and maintaining said water pressure between predetermined boundary values by switching in a nozzle when the water pressure exceeds a predetermined maximum value and switching out a nozzle when said water pressure drops below the predetermined minimum value.
Claim 15
Independent Claim
133 words
A method for controlling the moisture content of granular material such as moulding sand, comprising: feeding granular material to a mixing drum; driving said mixing drum; measuring at least one of the power input and driving torque of the driving means for said mixing drum; controlling the feed of water to a plurality of nozzles which are aligned with the interior of the mixing drum for introducing water into the mixing drum, as a function of at least one of said power input and driving torque; and measuring the water pressure upstream of said nozzles and maintaining said water pressure between predetermined boundary values by switching in a nozzle when the water pressure exceeds a predetermined maximum value and switching out a nozzle when said water pressure drops below the predetermined minimum value.
Claim 16
Dependent Claim
34 words
The method according to claim 13 comprising controlling a main control valve means located upstream of said pressure control device as a function of at least one of said power input and driving torque.
Claim 17
Dependent Claim
45 words
The method according to claim 14 comprising measuring the temperature of the granular material being fed to the mixing drum, and controlling said main control valve means as a function of both said temperature and at least one of said power input and driving torque.
Claim 18
Dependent Claim
65 words
The method according to claim 13 wherein measuring the water pressure upstream of the nozzle means and maintaining same between predetermined boundary values comprising maintaining a water column upstream of said nozzles, sensing when said water column reaches upper and lower predetermined levels, and switching in or out at least one of said nozzle means when said upper and lower predetermined levels, respectively, are detected.
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) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |