US2127693A - Pneumatic cement conveyer - Google Patents

Description

Aug. 23, 1938. w. A. M cCANLES S ET AL 2,127,693

PNEUMATIC CEMENT CONVEYER INVENTORS WILL/AM A. MCCANLESS ROBERT R. HENDERSON ATTORNEY.

Patented Aug. 23, 1938 PATENT OFFICE PNEUMATIC'CEMIENT CONVEYER William A. McCanless and Robert E. Henderson, Merced, Califi, assignors t0 Yosemite Portland Cement Corporation, Merced, Calif., a corpora.-

tion of Delaware Application April 16, 1937, Serial No. 137,261

'7 Claims.

This invention relates to pneumatic conveyers for finely divided or pulverulent materials, and particularly to means for continuously forcing dry Portland cement powder through conduits or pipes which may be several hundred feet long, from grinding mills to storage silos, by means of air under pressure.

The principal object of the invention is to provide improved apparatus for the above mentioned purpose whichwill be more effective than prior apparatus used for this purpose. I w

A feature of the invention is to provide a control of the air blast around the foot of the column of flowing cement.

Another feature is to provide a revolving propeller to continuouslycut oil cement from a compacted air-sealed feed column of cement and throw it outward into the air blast.

A further feature is an independent drive for such a propeller so that it may be operated at high speed unaffected by the motion of the com pacting screw.

A still further feature is the longitudinal adjustability of the propeller in relation to the compacting screw. I

A further feature is the provision of air booster nozzles adjacent the propeller to aid in throwing the loosened cement out into the main air stream.

A further feature is the provision of a cylinder around the propeller extending forward of the same into the main air stream.

A still further feature is the provision of perforated air ejecting pipes around the propeller housing and means for adjusting the angularity of the issuing air streams.

Other features and advantages of our invention will appear in the following description and accompanying drawing.

In the drawing:

Figure 1 is a vertical section taken centrally through our improved pneumatic cement conveying apparatus.

Figure 2 is a cross section of Figure 1 as seen from the line 22 thereof.

Figure 3 is an enlarged vertical section of the propeller shaft mounting and associated parts.

Before describing the drawing in detail, it may be stated that broadly it is old to continuously object of the screw compressed column being to obtain an air seal through which the compressed air released for conveying purposes cannot strike back into the source of supply of the powder (see Patents Nos. 1,202,088 and 1,258,911) Our apparatus operates on the same principle, but is considerably improved in construction over the prior apparatus used for this purpose, and gives better control over its operation.

In the drawing 'I is a gravity feed chute as leading the cement output of one or more grinding mills by gravity to a horizontally disposed cylindrical spiral conveyer box 2 in which is revolvably positioned a spiral conveyer 3 mounted on a hollow shaft 4.

The spiral conveyer fits nicely within its box or cylinder and is here shown as of double lead or flight construction of gradually decreasing pitch toward the right-hand end so as to gradually compress toward that end the material being conveyed by it in direction of the arrow from the chute I. The flight of the conveyer may be of triple or single lead if desired, though we have found that the double lead seems to operate more efliciently.

The hollow conveyer shaft 4 passes out of the closed end 5 of the box through a suitable stuffing box or gland 6 and is rotatably supported in one or more bearings as at 'l and has a driving gear 8 secured to it and preferably a ball or roller thrust collar interposed between the gear hub and the bearing as indicated at 9.

For the purpose of handling ground Portland cement, the spiral conveyer may be from about four to six inches in diameter, and at its forward end the conveyer box is flared outward as at I0 to a larger size and continues forward for about a foot as a larger cylinder I I, while surrounding and enclosing this'larger'cylinder II is a rectangular steel casing I2 closed at its rear end I 3 and welded or otherwise attached to cylinder I I so as to form an air-tight juncture therewith.

Casing I2 is open and flanged at I4 at its forward end and connected to a similarly flanged conical discharge pipe or duct I5 which tapers down to a round outer'end I5 where it connects to the conveyer pipe I6 for conveying the cement to the silo or other point desired.

Within the hollow spiral'conveyer shaft 4 is a propeller drive shaft I! to the inner end of which is attached a bladed propeller I8 for the purpose of cutting off and throwing a continuous rotary stream of cement from the compacted mass at its rear out through the forward end of cylinder I I intocasing I2.

It is desirable that this propeller be longitudinally adjustable in cylinder II to best suit the characteristics of various grades of ground materials being handled by the apparatus and to this end it is preferably provided with the shaft mounting as best shown in Fig. 3, and wherein the propeller shaft II is revolvably supported in oilless bushings I9 fitted within the-outer end of hollow shaft 4 and sealed against back pressure of air as by packing 20 held in place as by a threaded self-tightening gland 2 I.

At the outer or rear end of the propeller shaft is a driving pulley 23 and its supporting bearing 24. A yoke collar 25 on the propeller shaft between bearings I and 24 fitted with a yoked shifting lever 26 provides for slidi-ngthe propeller shaft longitudinally. The yoke lever may be moved either way and locked at any'point as by a bolt 21 projecting from a lug 28 on bearing 24 and operating a traveling yoke nut 29 engaged by the shifting lever 26. By this means the propeller may be adjusted in cylinder I I and locked at any position while free to rotate.

To inject air into the rear of casing I2 for forcing the powdered material through and out of cone I5, four perforated pipes 30 for compressed air are provided in quadrangular arrangement around cylinder II and the perforations 3| are directed forwardly in a manner to make the air streams converge.

To provide for proper angular adjustment of the perforations, we may gear all of the pipes together for simultaneous rotation as one is turned. Such gearing is shown in Figure 2 at 32. A bearing block 33 at each corner passes one of the pipes for turning and also revolvably supports the closed end of the adjacent pipe as indicated.

Each of the pipes is providedwith a suitable sleeve joint 35, to permit turning while each is connected to a service air pressure pipe 35. A handle 36,may be provided on any one of the pipes for simultaneously turning all of them and the outer end 3'! of the handle crank arm may be used as an indicator against suitable graduated points 38 arranged on the casing;

Besides the forward ejection of compressed air from perforated pipe 30, we provide several forwardly directed jet pipes 39 extending through the sides of cylinder II just in front of the propeller I8. These jets receive their air from a branch airpressure pipe line 40 under separate valve control 4 I.

By the construction and arrangement described, the powdered material from chute I to be conveyed is, in the operation of the pparatus, tightly compacted in the forward end of the conveyor box 2 against reverse flow of air, sliced off by the rapidly spinning propeller and thrown forward in cylinder II to be picked up by jets 39, which are preferably spirally arranged, and given a further spinning motion as it is hurled outward into the main air stream issuing from perforated pipes 30 all around cylinder I I and rapidly carried away through conical section I5 to the conveying pipe line.

While the apparatus has been developed particularly for the pneumatic conveying of cement, it may be adjusted through the means shown so as to successfully handle many kinds of finely divided materials.

Having thus described our improved pneumatic conveying apparatus, it will be evident to anyone skilled in the art that minor changes may be made within the. spirit of the invention and scope of the appended claims.

We claim:

1. In a pneumatic conveyer of the character described, a screw conveyer operatively mounted in a casing and arranged for compacting at its discharge end pulverulent material received at the other end, an enlarged casing enclosing the discharge end of the screw conveyer communicating with a discharge pipe for conveying the material to the desired point, means for forcing a stream of compressed air from said enlarged casing directed generally toward said discharge pipe, a rotary propeller adjacent the discharge end of said screw conveyer arranged for ejecting material from the screw conveyer into said enlarged casing for taking up by said air stream, and means operable -from without the casings for adjusting said propeller longitudinally of the screw conveyer to regulate its distance from the discharge end thereof.

'2. Ina pneumatic conveyer of the character described, a screw conveyer operatively mounted in a casing and arranged for compacting at its discharge end pulverulent material received at the other end, an enlarged casing enclosing the discharge end of the screw conveyer communicating with a discharge pipe for conveying the material to the desired point, a compressed air pipe arranged in said enlarged casing provided with orifices directed generally toward said discharge pipe, a propeller adjacent the discharge end of said screw conveyer arranged for ejecting material from the screw conveyer into said casing for taking up by the air stream from said compressed air pipe, and an extension of the screw conveyer casing embracing said propeller and projecting forward of the same into said enlarged casing.

3. In the construction specified in claim 2, means for ejecting compressed air into said extension in forwardly directed jets.

4. In the construction specified in claim 2, means for ejecting compressed air into said extension in forwardly and spirally directed jets.

5. In a pneumatic conveyer of the character described, a screw conveyer operatively mounted in a casing and arranged for compacting at its discharge end pulverulent material received at the other end, an enlarged casing enclosing the discharge end of the screw conveyer communicating with a discharge pipe for conveying the material to the desired point, and a plurality of straight compressed air pipes in said enlarged casing arranged about the discharge end of said screw conveyer and provided with perforations in their side walls directing air jets forward of said conveyer casing toward said discharge pipe.

6. In a pneumatic conveyer of the character described, a screw conveyer operatively mounted in a casing and arranged for compacting at its discharge end pulverulent material received at the other end, an enlarged cas'mg enclosing the discharge end of the screw conveyer communicating with a discharge pipe for conveying the material to the desired point, a plurality of straight compressed air pipes in said enlarged casing arranged about the discharge end of said screw conveyer and provided with perforations directed generally toward said discharge pipe, and means for turning said compressed air pipes to alter the direction of air streams from said perforations.

'7. In a pneumatic conveyer of the character described, a screw conveyer operatively mounted in a casing and arranged for compacting at its discharge end pulverulent material received at the other end, an enlarged casing enclosing the disgenerally toward said discharge pipe, and means for simultaneously turning all of said compressed air pipes to alter the direction of air streams from said perforations.

WILLIAM A. MCCANLESS.

ROBERT R. HENDERSON.

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