US3904132A

US3904132A - External regulation of internal air vent structure for hammermill

Info

Publication number: US3904132A
Application number: US467921A
Authority: US
Inventors: Robert P Olson
Original assignee: Individual
Current assignee: CHAMPION PRODUCTS Inc A CORP OF; California Pellet Mill Co
Priority date: 1974-05-08
Filing date: 1974-05-08
Publication date: 1975-09-09
Anticipated expiration: 1992-09-09

Abstract

An air valve structure in connection with a hammermill type of grinding mill to regulate the internal air recirculation system of said mill. Said air valve structure consists of a vent in a door supported plate member forming one side of the grinding chamber, a vent closure member, a screw rod supporting said vent closing member, said screw rod being threaded through the supporting door of said plate member, and means externally of said door operating said rod and said closure member to regulate said vent.

Description

United States Patent Olson EXTERNAL REGULATION OF INTERNAL AlR VENT STRUCTURE FOR HAMMERMILL [76] Inventor: Robert P. Olson, Rt. N0. 2, Box

657, Mound, Minn. 55364 [22] Filed: May 8, 1974 [21] Appl, No: 467,921

[52] US. Cl. 241/59 [Sl] Int. Cl." BOZC 23/26 [58] Field of Search 24 H5) [56] References Cited UNITED STATES PATENTS 3311494 4/]967 Peterson v. 241/59 X 3.598326 8/[971 Penncll H 24l/59 X Sept. 9, 1975 1702686 ll/l972 Jacobson 241/59 Primary Examiner-Granville Y. Custer, Jr.

Attorney, Agent, or FirmLeo Gregory 57] ABSTRACT An air valve structure in connection with a hammermill type of grinding mill to regulate the internal air recirculation system of said mill. Said air valve structure consists of a vent in a door supported plate member forming one side of the grinding chamber, a vent closure member a screw rod supporting said vent closing member, said screw rod being threaded through the supporting door of said plate member, and means externally of said door operating said rod and said closure member to regulate said vent.

2 Claims, 3 Drawing Figures EXTERNAL REGULATION OF INTERNAL AIR VENT STRUCTURE FOR HAMMERMILL BACKGROUND AND SUMMARY OF THE INVENTION A grinding mill of the hammermill type which traditionally was related to grinding feed products has developed significant usefulness in grinding a general variety of materials having industrial application. Many materials including many non-agricultural materials for efficient handling in a hammermill require a regulation of the internal air recirculation system therein. Hence, the control or regulation of internal air flow has significant importance.

It is an object of this invention therefore, to provide an external control means to regulate the internal air recirculation system of a hammermill.

The internal recirculation of air within a grinding chamber creates a low pressure area at the mouth of the outlet whereby there is a tendency to create a suction effect with respect to light weight ground material such that a portion of said ground material entering the mouth of the outlet is drawn back into the grinding cycle within the grinding chamber by action of said internal air recirculation thereby reducing the effective capacity of said grinding chamber to receive new material.

Hence, it is another object of this invention to improve the efiective grinding capacity of a hammermill through the regulation of its internal air recirculation system to more effectively discharge material from the grinding chamber.

It is also an object of this invention to improve the grinding efficiency of a hammermill by providing a more effective discharge of ground material therefrom by regulation of its internal air recirculation system.

More generally stated, it is an object of this invention to provide an air valve structure for regulation of the internal air recirculation system ofa hammermill which comprises a cover plate forming one side of the grinding chamber, an outer door supporting said cover plate in a spaced relation thereto, a vent in said cover plate, a closure member for said vent. a rod carrying said closure member. said rod being threaded through said door and means externally of said door to operate said rod and said closure member to regulate the opening of said vent.

These and other objects and advantages of the inven tion will be set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

FIG. 1 is a broken view in front elevation showing some portions in dotted line;

FIG. 2 is a broken view in perspective showing details of interior structure;

FIG. 3 is a broken view in central vertical section on an enlarged scale taken on line 33 of FIG. 1 as indicated.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawings, a hammermill type of grinding mill is indicated. The invention herein relates to the grinding chamber of said grinding mill and more particularly to the regulation of the internal air recirculation of said mill is shown as is believed necessary to support a description of the structure and function of the invention herein.

Said mill 10 comprises a housing 12 having a top wall 14,

front side walls

17 and 18 and a front bottom wall 19. A bottom supporting frame structure 20 is indicated.

Hinged onto said front side wall l7 is a conventional manner is an outer door 22. Extending from the free ends thereof are said door latch members 24 received and secured by keepers or locking members 26 carried by said side front wall 18. Depending from said bottom wall is an outlet or discharge chute 25 having an open top or mouth portion 26 formed in the bottom of said wall 19.

Within said housing 12 is a chamber 27. Mounted within said chamber in a conventional manner as onto the back wall thereof and spaced inwardly from the bottom and side walls thereof is a screen member 30. Said screen member defines the side wall of the grinding chamber 32 therein. An inlet chute 35 feeds into said chamber through the top wall l4. Mounted onto a driving shaft 37 extending inwardly of the back wall 38 of said housing within said grinding chamber is a rotor 40 formed of parallel spaced plate members hav ing hammers 42 respectively pivotally mounted between adjacent of said plate members and spaced circumfrentially about said rotor.

Said door 22 has mounted thereon in spaced relation thereto a plate member 50 which when said door is in closed position forms a cover or front wall of said screen 30 and having a configuration to fit within the periphery of the leading edge portion of said screen and providing a support therefor.

Said plate member is held in spaced relation with respect to said door by a plurality of posts 52 secured therebetween as by welding or by bolts as indicated in FIG. 3.

Formed centrally of said plate member 50 is a circular opening or vent S5. Mounted onto the outer side of said door as by welding in axial alignment with said vent is a post member 60 having a threaded bore. Extending through said post member is a rod 62. Carried by the inner end portion of said rod inwardly of said plate member 50 is a closure member 64 for said vent 55. In the embodiment of the invention here presented, said closure member is shown to be a relatively flat cone in form to be self-centering within said vent 55. Said closure member may be rigidly secured to said interior end of said rod or may be rotatively secured thereto in a conventional manner. as may be desired.

Secured to the outer end portion of said rod is a manually operable means 66 here shown as a hand wheel. A sufficient portion of said rod 62 will be threaded for axial movement by rotation relative to said post mem ber 60 for regulation of the opening of said vent by an axial movement of said closure member 64.

OPERATION In operation, the centrifugal action of the rotor 40 and its hammer 42 drive the material being ground around the periphery of the grinding chamber adjacent the inner surface of the screen 30. The air stream carry ing the material defines a like path and carries out of the screen the material which has been ground sufficiently to discharge through the mesh sides of the screenv The material discharged through the screen into the chamber 27 falls in the direction of and dis charges through the outlet 25.

The centrifugal action of the air stream creates a low pressure area centrally of the rotor and the grinding chamber. The presence of said low pressure area results in air passing through the vent 55 from the chamber 27 back into the grinding chamber 32 for a complete cycle of internal air recirculation. The rotor travels at a high velocity. The movement of the air from the chamber 27 through the vent 55 into the grinding chamber 32 is of sufficient velocity to create a low pressure area adjacent the mouth 26 of the outlet 25.

In the grinding of heavier materials. such as com. the ground material has sufficient weight to discharge through the chute without being affected significantly by the low pressure area adjacent said mouth portion 26 of said chute. However, with lighter weight materials. such as with oats, for example as an agricultural material or with commercial materials which are reduced to the fineness of powders or the like, the low pressure area adjacent the mouth 26 of said discharge chute does have significant effect in drawing or sucking out of and away from said mouth 26 a substantial portion of the material which would otherwise discharge therethrough. When this occurs, a portion of the material already ground and ready for discharge is drawn back with the air stream into the grinding chamber to take up unnecessarily some of the capacity of the grinding chamber which could otherwise be more effectively used to receive in its place material being fed therein through the inlet 35. At the same time, the efficiency of the operation of the grinding chamber is impaired in going through the effort of regrinding materials already sufficiently ground.

it has been found that with the invention herein the effect of the low pressure area adjacent the outlet 25 can be controlled so effectively as to have a negligible effect upon various materials being ground and discharged therethrough by controlling the velocity and- /or the volume of the air stream passing from the chamber 27 through the vent 55 into the grinding chamber 32. It has been found that this air stream is very effectively regulated by the use of the vent closure member 64 to adjust or regulate the opening of the vent 55. The velocity and the volume of moving air moving through the grinding chamber controlled and slowed down by closing down the vent 55. The extent to which this is done in any given case depends upon the particular material being ground to obtain the most efficient and effective use of the grinding chamber and to obtain a substantially full discharge of ground material through the discharge chute 25.

The vent closure member 64 is very readily regulated by the hand wheel 66 which is external of the door 22 and regulates the position of said closure member 64 by means of said screw rod 62.

This invention, although it appears to be very simple in structure, represents and has proved to provide a very significant and effective improvement in the operation of a hammermill and particularly in regulating the internal air recirculation system to obtain a high degree of grinding capacity within the grinding chamber 32 and a high degree of efficiency and effectiveness in grinding material through a single grinding cycle. The invention herein has proved to be very satisfactory under operating conditions.

It will of course be understood that various changes may be made in form, details, arrangement and proportions of the parts without departing from the scope of the invention herein which, generally stated, consists in an apparatus capable of carrying out the objects above set forth, in the parts and combination of parts disclosed and defined in the appended claims.

What is claimed is:

1. An air valve structure for a hammermill, having in combination a housing having a grinding chamber therein,

a screen forming the side walls of said grinding chamber,

a plate member forming a front wall of said grinding chamber,

said plate member having a circular opening therein,

a conical closure member regulating the opening of said plate,

a door carried by said housing,

means mounting said plate member on said door in spaced relation thereto,

a rod carrying said closure member at its interior end and having its outer end portion extending outwardly of said door, and

means on said outer end portion of said rod for moving said closure member axially of said circular opening.

2. The structure set forth in claim, wherein said outer end portion of said rod has a threaded engagement with and extends through threaded means on said door for axial movement in connection therewith.

Claims

1. An air valve structure for a hammermill, having in combination a housing having a grinding chamber therein, a screen forming the side walls of said grinding chamber, a plate member forming a front wall of said grinding chamber, said plate member having a circular opening therein, a conical closure member regulating the opening of said plate, a door carried by said housing, means mounting said plate member on said door in spaced relation thereto, a rod carrying said closure member at its interior end and having its outer end portion extending outwardly of said door, and means on said outer end portion of said rod for moving said closure member axially of said circular opening.