US2443819A

US2443819A - Machine for blast cleaning with grit such articles as castings

Info

Publication number: US2443819A
Application number: US676271A
Authority: US
Inventors: Ernest F Fisher
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-06-12
Filing date: 1946-06-12
Publication date: 1948-06-22
Anticipated expiration: 1965-06-22

Description

E. F. FISHER MACHINE FOR BLAST CLEANING WITH GRIT SUCH ARTICLES AS CASTINGS Filed June 12, 1946 June 22,-1948.

IN V EN TOR.

Patented June 22, 1948 OFFICE MACHINE FOR BLAST CLEANING WITH GRIT SUCH ARTICLES AS CASTIN GS Ernest F. Fisher, Meredith, N. H.

Application June 12, 1946, Serial No. 676,271

moving scale and moulding sand.

According to this invention a stream of sand or metallic shot or grit merges with a high velocity air stream and attains the same velocity as the air stream. This high velocity mixture of air and gritty particles is directed against the surfaces of the castings and loosens the sand and scale therefrom. The spent particles of grit are collected and put back in the air stream for re-use, while the fine dust arising from the operation and the spent air are exhausted from the apparatus and conducted to a dust collector.

The invention will be further described in connection with the accompanying drawings in which Figure 1 is a vertical cross section taken on line I -l of Figure 2. Figure 2 is a. horizontal cross section taken on line 22 of Figure 1. Figure 3 is a, vertical section showing blower l 2 which supplies the high velocity air for projecting the stream of grit that flows through tube 6 into the orifice of nozzle [6. Figure 4 is a vertical section of another form of blower. 3

Referring now to these drawings, the apparatus of Figures 1 to 3 comprises an enclosure or casing I which, with hinged hopper 2 forms a reason ably air tight enclosure for the castingsto be cleaned. Within this enclosure is ram 3 which is designed to be raised and lowered in a reciprocating fashion by means of the revolving pinions 4 and the cooperating racks 5 which are attached to ram 3. This reciprocating vertical motion of the ram is affected by suitable reversing and limit switches controlling a motor (not shown) for driving shaft 4a.

Ram 3 is guided in casing I by liners I which afford clearances between the ram and the walls of the enclosure for the spent grit to drop down into conveyor trough 8. This spent grit is conveyed by the spiral conveyor 9 into elevator I l) which elevates the grit so that it will flow into separator I 041 to be cleaned. The refuse is discharged through spout II and the cleaned grit flows by gravity through flexible tube 6a and connecting tube 6 into nozzle l6 of blower [2.

The hopper 2 which is hinged to the main casing I at point H serves several purposes. It serves as a door for casing I. It serves as a spillway for the castings as they roll oif the inclined top of ram 3. It serves to convey the 6 Claims. (Cl. 51-44) castings from the floor to the upper part of casing I or mother words, to load the machine. The hopper 2 is raised and lowered by the winch H.

In operation, castings are placed in hopper 2 whenit is in a lowered position as shown in dotted lines. It is then raised by the winch I7 and latched in position and the castings discharge into casing I dropping on ram 3 in its lowermost position as shown. The ram 3 is started'reciprocating slowly up and down while the blower I2 discharges the air stream mixed with grit onto the castings as they rise upward and spill on the inclined top of ram 3 into hopper 2. As the ram descends the castings roll ofi hopper 2 back onto ram 3. This repeated up and down motion of the ram turn the castings over and over thus presenting all surfaces of the castings to the blast of air and grit.

The spent grit drops down through the clearances betweenram 3 and. the walls of casing l into trough 8 Where. the grit is conveyed by spiral conveyor 9 to the elevator H] which elevates the. grit to separator Illa where it is cleaned, the refuse passing out through spout II and the cleaned grit flows by gravity down tube 6 into the orifice of nozzle 16 of blower l2. The dust laden air is exhausted from casing I through opening I8 which connects with an exhaust fan which maintains a slight negative pressure within the apparatus to prevent dust from dissipating into the room.

After the castings are cleaned the ram 3is raised to its topmost position or limit of travel upward and the castings spilled into hopper 2 which is then lowered to the floor by winch l1, thus completing the operation of cleaning.

The method of propelling the grit is shown in Figure 3. The grit is fed through tube 6 to the orifice of the blower discharge nozzle [6 and does not come in contact with any part of the blower housing or impeller. Thus there is no erosion of the parts. Sufficient velocity is imparted to the air by the impeller [9 to give the grit a velocity of approximately28,000 feet per minute which is suificient to produce a good job of cleaning.

Any type of pressure blower can be used for supplying the necessary air for propelling the grit. The nozzle It; can be swung back and forth about the axis 20 through an arc suflicient to cover any blast area in casing I so that all castings are reached by the blast. This nozzle can be separate and distinct from the blower as in Figure 4. The blower in Figure 4 discharges the air into nozzle is which swings through an are ing hopper attached to said casing and also adapted to form a closure for said opening, means to raise and lower said hopper, a vertically reciprocating ram for tumbling said material within said casing, the top of said ram being inclined downwardly toward said hopper, means to direct a high velocity stream of air and grit against said material to be cleaned, and means to reciprocate said ram.

2. A blast cleaning machine comprising, in combination, a vertical casing to contain material to be cleaned, the upper portion of said casing having an inwardly sloping side provided with an opening therein, a loading and unloading hopper attached to said casing and also adapted to form a closure for said opening, a

vertically reciprocating ram for tumbling saidmaterial within said casing, the top of said ram being downwardly inclined toward said hopper, means to reciprocate said ram, the upper limit of movement of the top of said ram being above the lower edgeo'f-fsaid opening, mean to direct a high velocity stream of air and grit against said material to be cleaned, and means to raise and lower said hopper.

3. A blast cleaning machine comprising, in combination, a vertical casing to contain material to be cleaned, the upper portion of said oasing having an inwardly sloping side provided with an opening therein, a loading and unloading hopper attached to said casing and also adapted to form a closure for said opening, a vertically reciprocating ram for tumbling said material within said casing, the top of said ram being downwardly inclined toward said hopper, means to reciprocate said ram, the upper limit of movement of the top of said ram being abovethe lower edge of said opening, the lower limit of movement of .saidram being below the lower edge ofsaid opening, means to direct a high velocity stream of air and grit against said ma- 4 terial to be cleaned, and means to raise and lower said hopper. I

4. A blast cleaning machine comprising, in combination, a vertical casing to contain material to be cleaned,.the upper portion of said casing having an inwardly sloping side provided with an opening therein, a loading and unloading hopper attached to said casing and also adapted to form a closure 'for said opening, means to raise and lower said hopper, a vertically reciprocating ram for tumbling said material within said casing, the top of said ram being inclined downwardlyjtoward said hopper, nozzle means swingable back and forth for directing a high velocity stream of air and grit against said material to :be cleaned, and means to reciprocate said ram.

5.A' blast cleaning machine comprising, in

combination, a vertical casing to contain material to be cleaned, the upper portion of said casing having an inwardly sloping side provided with an opening therein, a loading and unloading hopper attached to said casing and also adapted to form a closure for said opening, a vertically reciprocating ram fortumbling said material within, said casing, the top of said ram being downwardly inclined toward said hopper, means to reciprocate said ram, the upper limit .of movement of the topof said ram being above the lower edge of said opening, nozzle means swingable back and forth for directing a high velocity stream of air and grit against said material to be cleaned, and means to raise and lower said hopper.

6. A blast cleaning machine comprising, in combination, a vertical casing to contain material tobe cleaned, the upper portion of said casing having an inwardly sloping side provided with an opening therein, a loading and unloading hopper attached to said casing and also adapted to form a closure for said opening, a vertically reciprocating ram for tumbling said material within said casing, the top' of said ram being downwardly inclined toward said hopper, means to reciprocate said ram, the upper limit of movement of the top of said ram being above the lower edge of said opening, the lower limit of movement of said ram being below the lower edge of said opening, nozzle means swingable back "and forth for directing a high velocity stream of'air and grit against said material to be cleaned, and means to raise and lower said hopper.

ERNEST F. FISHER.