US3285422A

US3285422A - Sand trap

Info

Publication number: US3285422A
Authority: US
Publication date: 1966-11-15
Anticipated expiration: 1983-11-15

Description

W. R. WILEY Nov. 15, 1966 SAND TRAP 2 Sheets-Sheet 1 Original Filed Jan. 5, 1963 INVENTOR.

Nov. 15, 1966 w. R. WILEY 3,285,422

SAND TRAP Original Filed Jan. 5, 1963 2 Sheets-Sheet 2 O I; A? 4.

T t: 5% I 4; E If I l v l 1 I d.

INVENTOR.

United States Patent 1963. This application Aug. 10, 1965, Ser. No. 482,995 4 Claims. (Cl. 210512) This application is a continuation of my copending application, Serial No. 249,280, filed January 3, 1963, and now abandoned.

This invention relates to sand traps and particularly to a device for separating sand or the like from Water in Water pumping and delivery systems.

It is an object of the present invention to provide a sand trap having a high degree of effectiveness in removing sand and other similar particles from Water being pumped.

It is another object of the present invention to provide a sand trap of the centrifugal separator type which is effective to direct the water in a manner obtaining controlled rotational velocity of the water and causing the sand and other heavy particles to accumulate at the center of the trap.

It is still another object of the present invention to provide a sand trap having means for directing the separated sand to a special repository, where it is stored apart from the clean water flowing through the device.

It is a still further object of the present invention to provide a sand trap which is relatively inexpensive to fabricate, which is of simple, rugged construction, which is easy to maintain and clean, and which possesses a long, useful life.

These and other objects of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings,

wherein:

FIGURE 1 is a vertical sectional view of a sand trap made in accordance with the present invention; and

FIGS. 2 and 3 are sectional views of the structure illustrated in FIG. 1, taken along the lines 22 and 33 thereof, respectively.

Referring now to the drawings, the sand trap will be seen to include a sheet metal casing 10 having an enclosing circular cylindrical side wall 12 integrally joined to a top wall 14 and a bottom wall 16. A plurality of depending legs 18 are fastened to the exterior of the side wall 12 adjacent to the bottom thereof and serve to support the casing 10 on a suitable supporting surface with the axis of the enclosing side wall 12 disposed in a vertical attitude.

The sidewall 12 has an inlet opening 20 at approximately the middle thereof, through which water is admitted to the interior of the casing 10 from an inlet conduit or pipe 22. The inlet pipe 22 is of circular cross section and is arranged to direct incoming water in a path spaced radially inwardly from the side wall 12 and transversely between the side Wall 12 and the axis about which the side wall is generated. Water is discharged from the casing 11) through an outlet opening 24 formed in the side wall 12 and communicating with an outlet pipe 26 integrally formed with the side Wall 12. The outlet opening 24 is located at the upper end of the side Wall 12 adjacent the top wall 14 and is spaced above the level of the inlet opening 20'.

Within the casing 10 are arranged a pair of baffles dividing the casing 10 into separate chambers or compartments. A lower baffle 28 extends radially inwardly from the side wall 12 in a plane transverse to the axis of the side wall 12 and spaced slightly below the inlet opening 20. The baffle 28 is of annular shape to define a large central opening 30 providing communication to a storage chamber or sand respository 32 located between the lower 3,285,422 Patented Nov. 15, 1966 bafiie 28 and the bottom wall 16. An upper baflie 34 is supportingly connected at its large diameter end to the interior of the side wall 12 on a plane above the inlet opening 20 and below the outlet opening 24. The baffle 34 extends radially inwardly and downwardly from the side wall 12 toward the axis of the casing side wall and terminates at its small diameter end in a central opening 36. A drainage conduit or pipe 38 is Welded at one end thereof to the portion of the baffle 34 defining theopening 36 anddepends from the bafiie 34 through the opening 30 in the lower bafile 2-8. It will be seen that the drainage pipe 38 is disposed at a level opposite from the inlet opening 20 and its of a diameter less than the lower bafiie opening 30 to define an annular space between the opening 30 and the outside of the pipe 38.

The space between the upper bafiie 34 and the lower bafiie 28 subdivides the casing 10 into a first or lower separation chamber 40, whereas the portion of the casing 10 between the upper baffle 34 and the top wall 14 forms a second or upper separation chamber 42. The flow of water from the lower chamber 40 to the upper chamber 42 is through an opening 44 formed in the upper bafie 34. A center plate 46 extending the entire length of and diametrically across the drainage pipe 38 subdivides the drainage pipe 38 into two paths and serves to restrain rotation of water and sand therein. Access to the sand storage repository 32 for maintenance purposes is provided by a normally closed manhole 48 formed in the casing side wall 12. However, sand is normally removed from the repository 32 through a clean-out pipe 50 connected to the bottom wall 16 and closed by any suitable means such as a cap 52. A center plate 54 extends diametrically across the clean-out pipe 50 and along the length thereof to limit swirling of sand in the pipe 50. A pair of upstanding ribs 56 on the bottom wall 16 extends radially outwardly from opposite sides of the pipe 50 to a position closely adjacent the side wall 12. The ribs 56 serve to trap the sand and limit its rotation in the repository 32.

In operation, Water entering the casing 10 through the inlet pipe 22 flows in the path indicated by the arrows of FIGS. 2 and 3 until it finally emerges from the casing 10 through the outlet pipe 26. It will be seen that in entering the chamber 40 incoming water flows in a direction generally coincident with the axis of the cylindrical inlet pipe 22. This axis extends in a path spaced between the vertical axis of the casing 10 and the side wall 12. As the incoming water continues its course, it is directed in a generally circular path rotating about the axis of the side wall 12 until it flOWs upwardly through the upper baflle opening 44 into the upper chamber 42, where it will continue rotating until it flows out of the casing 10 through the outlet pipe 26. In rotating within the chambers 40 and 42, the sand that is carried by the water tends to move at a lower speed, due to its heavier weight. As a result, the faster traveling water is thrown to the outside of the tank and the heavier material is forced to the center. In prior sand traps, water has been introduced in a path tangential to the side wall 12 and it i believed that the arrangement of the present construction, in which the water is introduced in a direction away from the side wall 12 (that is, nontangentially to the side wall 12), increases the tendency of the sand to drop out of the water and to be forced to the center of the casing 10. In understanding why the sand tends to move toward the center, it is important to appreciate the fact that the ligher, fastermoving water possesses a greater centrifugal force, this resulting from the fact that the formula for centrifugal force equals weight radius in feet x revolutions in minutes squared .00034, or .O0034WRN It will therefore be seen that the centrifugal force diminishes quite rapidly as the speed is reduced, inasmuch as the square of the speed of rotation is a factor in determining centrifugal force. Therefore, slight changes in the speed of rotation will have a marked effect upon the centrifugal force. The pressures existing in the water at the outer diameter of the chambers 40 and 42 are greater, thereby tending to force the sand inwardly. The upper bafile 34 is effective to guide the sand inwardly so that it will fall through the opening 30 into the sand repository 32. Additionally, the upper baffle 34 provides a controlled path for the flow of fluid, permitting the fluid to freely rotate within the chambers 40 and 42 and providing an opening 44 by which the water may flow from the chamber 40 to the chamber 42 with a minimum of obstruction. The rotation of fluid in the upper chamber 42 also tends to force the sand inwardly and such sand as settles on the upper baffle 34 in the chamber 42 will be free to falldown the baffle 34 through the drainage pipe 38 into the sand repository 32. Thus, sand separated in the upper chamber 42 will not be commingled with clean water circulated in this chamber.

In one embodiment of the present invention, a casing was built having a ten-inch diameter inlet pipe 22 and 1250 gallons of water per minute were pumped through the unit. This produces a velocity of 350 feet per minute at the inlet and outlet with about 167 feet per minute average at the mid-radius (the velocity at the center of the casing being zero). In computing the formula .00034WRN to determine the centrifugal force of the water and sand, it will be noted that water weighs approximately 60 pounds per cubic foot and sand approximately 100 pounds per cubic foot. Assuming that N equals 25 revolutions per minute for water, it is believed that a slower rate of about revolutions per minute would be correct for sand. On this basis, WN equals 60 625 or 37,500 for water and 100x225 or 22,500 for sand. It will thus be seen that the centrifugal force of water is substantially greater than that of the sand in the device of the present invention and the pressure of the water at the outside of the casing chambers will force the sand to the middle. A sand trap made in accordance with the present invention has been found to remove approximately 99.75% of all sand in the water pumped through the device.

While it will be apparent that the preferred embodiment herein illustrated is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A device for separating sand from water, including a casing having a generally cylindrical enclosing side Wall formed about a substantially vertical central axis, a bottom wall and a top wall, an inlet in said side wall arranged to direct sand bearing water therefrom into said casing along a path offset from said axis and spaced from said side wall and thereby produce rotation of water about said axis, a 'bafltle extending radially inwardly from said Wall substantially perpendicularly to said axis and located above said bottom wall and beneath said inlet, a sand storage chamber in said casing between said bafile and said bottom wall, means including rib means in said storage chamber for retarding the rotation of sand and water therein, said baffle having a central opening for the passage of sand from a location above said bafile to said storage chamber, said bafile being otherwise substantially imperforate, and a water outlet in said side wall located above said inlet and baflle means disposed between said inlet and said outlet for preventing the direct flow of water from said inlet to said outlet without preventing the direct flow of sand from' said inlet to said central opening.

2. A device for separating sand from water including a casing having a generally cylindrical enclosing side wall disposed about a substantially vertical central axis, an inlet in said side wall arranged to direct sand-bearing water therefrom into said casing in a path offset from said axis and spaced from said side wall and thereby produce rotation of water about a lower baffle extending inwardly from said side wall at a location beneath said inlet, said lower baflle having a central opening therethrough, a generally conical upper baffie extending radially inwardly and downwardly from said side wall at a level above said inlet, a conduit depending from said upper baflle at the center thereof for directing sand from above said upper bafile to a location beneath said lower baffle, said conduit being of a diameter smaller than the opening in aid lower bafile to provide space for the downward flow of sand from space between said baflles through the opening in said lower baffle, said upper =bafile having an opening therethrough in a location spaced radially outwardly from said conduit for the upward flow of water therethrough, and a water outlet in said casing disposed above said upper baffle.

3. The structure set forth in claim 1 including means depending from said baflle means through said central opening for communicating sand from a location above References Cited by the Examiner UNITED STATES PATENTS 1,202,356 10/1916 Blackmer 210-304 2,491,801 12/1949 Debrey 210-512 vX 3,129,066 4/1964 Ambrogi et al. 210-512 X 3,131,043 4/1964 Burdock 55-346 3,204,772 9/ 1965 Ruxton 210-512 REUBEN FRIEDMAN, Primary Examiner.

J. DE CESARE, Assistant Examiner.

Claims

1. A DEVICE FOR SEPARATING SAND FROM WATER, INCLUDING A CASING HAVING A GENERALLY CYLINDRICAL ENCLOSING SIDE WALL FORMED ABOUT A SUBSTANTIALLY VARTICAL CENTRAL AXIS, A BOTTOM WALL AND A TOP WALL, AN INLET IN SAID SIDE WALL ARRANGED TO DIRECT SAND BEARING WATER THEREFROM INTO SAID CASING ALONG A PATH OFFSET FROM SAID AXIS AND SPACED FROM SAID SIDE WALL AND THEREBY PRODUCE ROTATION OF WATER ABOUT SAID AXIS, A BAFFLE EXTENDING RADIALLY INWARDLY FROM SAID WALL SUBSTANTIALLY PERPENDICULARLY TO SIAD AXIS AND LOCATED ABOVE SAID BOTTOM WALL AND BENEATH SAID INLET, A SAND STORAGE CHAMBER IN SAID CASING BETWEEN SAID BAFFLE AND SAID BOTTOM WALL, MEANS INCLUDING RIB MEANS IN SAID STORAGE CHAMBER FOR RETARDING THE ROTATION OF SAND AND WATER THEREIN, SAID BAFFLE HAVING A CENTRAL OPENING FOR THE PASSAGE OF SAND FROM A LOCATION ABOVE SAID BAFFLE TO SAID STORAGE CHAMBER, SAID BAFFLE BEING OTHERWISE SUBSTANTIALLY IMPERFORATE, AND A WATEWR OUTLET IN SAID SIDE WALL LOCATED ABOVE SAID INLET AND BAFFLE MEANS DISPOSED BETWEEN SAID INLET AND SAID OUTLET FOR PREVENTING THE DIRECT FLOW OF WATER FROM SAID INLET TO SAID OUTLET WITHOUT PREVENTING THE DIRECT FLOW OF SAND FROM SAID INLET TO SAID CENTRAL OPENING.