US2568972A - Sand trap - Google Patents

Description

Sept. 25, 1951` l.. A. slFoRD 2,568,972

- SAND TRAP Filed May 15, 195o lll/- Ulli (ttornegs Patented Sept. 25, 1951 SAND TRAP Lewis A. Safford, Watertown, N. Y., assigner to The New York Air Brake Company, a corporation of New Jersey Application May 15, 1950., Serial No. 161,951

S Claims.

This invention relates to track sanders of the air-operated type and aliords a very simple structure which is characterized by close control of the rate at which sand is delivered. Moreover, the sander is not sensitive to position, and so can be mounted at considerable inclinations in case of need.

The rate of sand delivery can be varied between 1/2 and at least 21/2 pounds of sand per minute, and when set for any desired sand rate will maintain that rate with unprecedented uniformity.

The present invention will now be described by reference to the accompanying drawing in which:

Figs. l and 2 are vertical sections taken through the sander on planes at 90 to each other, Fig. 1 being a section on the line of Fig. 2, and Fig, 2 being a section on line 2 2 of Fig. l.

The body of the sander is preferably cast in one piece and includes a, mounting flange E by which it is connected with the sand supply. The sand enters at l, iiows along a baliie 8 and accumulates in a pocket 9 behind a dam which curves upward and terminates in a crest I 2. The baille 8 extends from the right-hand side wall of the body and curves down so that it overhangs the crest I2 and terminates at I3 at a level below the crest I2 and within the pocket 9. The plug I4 closes a clean-out opening. The configuration shown in the drawing and above described was adopted largely because it conforms to standards adopted by applicants assignee and is known to be desirable.

Below the crest l2 is a whirl chamber I5. This is generally cylindrical in form and its geometrical axis is preferably horizontal. The axis is located below and is shown as being approximately parallel with the crest I2. Screwed into threaded openings on opposite ends of the whirl chamber I5 are interchangeable fittings I6 and I1. The fitting I6 is provided with an air nozzle I8 which discharges along the axis of chamber I5. The air line is connected to the fitting I6 by a union generally designated by the numeral I9. The fitting I1 is connected by a union nut 2| with the discharge line 22. A Venturi throat member 23 of rubber-like material is mounted in the fitting and may be withdrawn ,upon removal of the nut 2| and connection 22.

The geometrical axis of the Venturi throat 23 coincides with the axes of the cylindrical Whirl chamber I5 and the nozzle I8. By interchanging the fittings I6 and I'l it is possible to produce right-hand and left-hand assemblies, according to principles already used in this art.

The body casting includes an air entrance shroud 24 which defines the atmospheric air passage 25. A drip rim 26 is designed to divert rain water to which the sander body may be exposed. The passage 25 is separated from the sand pocket and the suction chamber by a wall 2l'. Formed near the top of the wall 2`| is a port 28 which serves as a nozzle and directs air against the lower side of the curved baiile 8. This air is deflected downward, strikes the surface of sand in the pocket behind the crest I2, and sweeps sand from the surface over the crest so that it falls in a cascade into the whirl chamber I5.

A second port formed in the wall 21 receives a bushing 3| which also serves as a nozzle and directs atmospheric air from the passage 25 against the lower side of the upwardly curving wall near its junction with the wall of the whirl chamber. The bushing 3| is interchangeable so that bushings having different diameters of bore may be substituted. To give access to the bushing 3| the threaded plug 32 clearly shown in the drawing can be removed. The plug 33 is iixed in place and is used to close permanently the hole drilled preparatory to drilling the port 28.

Intensity of stirring action effected by nozzle 28, and consequently the sand rate, are determined by interchanging Ibushings 3|. The larger the port in the bushing 3l, the lower the sand rate, because less air then passes through the nozzle 28. In prior commercial constructions the port 28 was provided with interchangeable bushings and these were interchanged to control the sand rate. In the prior constructions there was no port analogous to that in bushing 3|.

At least a substantial part of the improved result secured with the sander of the present application, is attributable to the fact that the nozzle 28 is completely stabilized. Its size and location are fixed once and for all, and no concessions have to be made to accommodate interchange.

There is, however, another factor that exercises a possibly more important effect. The nozzle 3| discharges across the top of the whirl chamber I5. This iiow is below the crest I2, so that it can exert no disturbing effect on the action of the jet from the nozzle 28. The flow from nozzle 3| is approximately tangential to the wall of the whirl chamber l5, and so causes active whirling motion of air in the chamber l5. This whirling air picks up any sand which may have dropped to the bottom of the chamber. As a consequence, the sand is kept in suspension and is drawn out continuously and uniformly through the Venturi throat 23 lby the air jet issuing from the nozzle I8.

I claim:

l. In a rail sander the combination of a housing enclosing a Whirl chamber of circular cross-section and a sand pocket located at a higher elevation than the whirl chamber and having a sand inlet passage and a sand retaining dam with its crest so located that sand owing over the crest will fall into the whirl chamber; ejector means comprising a nozzle and a throat both substantially coaxial with the Whirl chamber, and the throat affording a discharge path from said chamber; a connection for supplying air under pressure to said nozzle; a discharge connection at the exit end of said throat; and means affording two inlets for atmospheric air so arranged that air from the first iiows in contact with sand in the pocket toward the crest of the dam, and air from the second enters the whirl chamber tangentially.

2. A sander as dened in claim l in which the axis of the circular whirl chamber is approximately parallel with the crest of the dam.

3. In a rail sander, the combination of housing means enclosing a sand-receiving pocket bounded on one side by a sand retaining dam having a crest, a sand supply passage leading to said pocket and a cylindrical suction chamber located below said crest; means comprising an air jet nozzle with compressed air supply and Venturi throat with discharge connections, said nozzle and throat being axially alined with the cylindrical suction chamber and with one another and located at opposite ends of the cylindrical chamber, first means for admitting atmospheric air to said housing and so directing it that it flows in contact with the surface of retained sand and toward said crest; and second means for admitting atmospheric air to said housing and directing it in a path substantially tangential to the cylindrical wall of said suction chamber.

4. A sander as dened in claim 3 in which the axis of the cylindrical suction chamber is substantially parallel with said crest.

5. A sander as dened in claim 3 in which the axis of the cylindrical suction chamber is substantially parallel with said crest and said second means directs the entering air in a generally horizontal stream across the top of the suction chamber and wholly below said crest.

6. In a rail sander, the combination of a body having a sand pocket one wall of which curves upward to form a damand terminates in a crest, a generally cylindrical suction chamber arranged with its axis beneath said crest so that sand owing over the crest tends to fall approximately diametrically through said chamber, a baille curved oppositely to the curved wall of the sand pocket and extending from one Wall of the body over said suction chamber and crest and thence curving downward to a point near the middle of the pocket at a level below the crest, a gravity sand supply connection leading to the sand pocket, and an air inlet port arranged to direct atmospheric air above and across said crest and against the lower side of said curved baille; a Venturi throat coaxial with said cylindrical suction chamber and leading therefrom to a point of discharge; a nozzle arranged to direct air under pressure substantially along the axis of said suction chamber and into said throat; and means forming a second air inlet port arranged to direct atmospheric air in a direction approximately tangential to the cylindrical suction chamber across the top of the chamber and below said crest.

7. In a rail sander, the combination of a body having a sand pocket one wall of which curves upward to form a dam and terminates in a crest, a suction chamber beneath the pocket and to which sand may iiow over said crest, a baillle curved oppositely to the curved wall of the sand pocket and extending from one wall of the body over said suction chamber and crest and thence curving downward to a line of termination near the middle of the pocket and at a level below the crest; a gravity sand supply connection leading to said pocket, and an air inlet port arranged to direct atmospheric air above and across said crest and against the lower side of said curved baiiile; a Venturi throat leading from said suction chamber to a point of discharge; a nozzle arranged to direct air under pressure across said suction chamber and into said throat substantially in the direction of the axis of the throat; and supplemental means for admitting atmospheric air to said suction chamber in a stream directed against the lower face of the upwardcurving wall which forms said dam.

8. The combination defined in claim 7 in which the supplemental means for admitting atmospheric air is a removable bushing the size of whose bore determines the rate at which said air is admitted.

LEWIS A. SAFFORD.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number f Name Date 1,854,994 Light et al Apr. 19, 1932 2,409,728 Baldwin Oct. 22, 1946

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