United States Patent 3662709

This invention is an improved spray equipment for use with a cylindrical metal mold which is rotated about its horizontal axis. A stationary support is mounted adjacent one end of the cylindrical metal mold and supports a vertically adjustable spray lance. The spray lance is moved longitudinally into and out of the bore of the cylindrical mold. Tiltable means are provided on the stationary support for keeping the end of the spray lance along the axis of the cylindrical metal mold out of contact with the inside of the cylindrical metal mold.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
118/321, 118/681, 239/227
International Classes:
B22D13/10; (IPC1-7): B05C7/02
Field of Search:
118/7,318,321,317,323 239
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Primary Examiner:
Mcintosh, John P.
The preferred embodiments of the invention having been thus described by way of illustration rather than limitation, what is claimed is

1. A spray coater for spray coating the interior of a substantially horizontal axis rotating cylinder without mechanical contact with the interior thereof comprising a stationary support fixedly mounted adjacent the location of one end of such cylinder, a hollow spray lance having an end projectible into said cylinder from said one end of the cylinder to adjacent the other end of the cylinder while free of contact with the interior of said cylinder and said lance having a laterally directed nozzle thereon adjacent its said projectible end and means for receiving a supply of a substance to be sprayed adjacent its other end for flow through said lance and out through said nozzle, a lance carrier fixedly positioned on said support in operation comprising a pair of guide wheels on axes in parallel planes spaced longitudinally of said lance from one another and directly engaging said lance both on the same side thereof for supporting and positively positioning said lance on a predetermined longitudinal alignment when the lance is held against said wheels while permitting it to move longitudinally of itself along such cylinder axis while the cylinder is rotating and means opposed to and bearing against the opposite side of the lance from said wheels holding said lance against said wheels.

2. A spray coater as set forth in claim 1 in which said lance is non-circular in cross section having a longitudinal ridge projecting beyond its outer contour and at least one of said guide wheels has a circumferential groove therein embracing said ridge to prevent said lance from rotating about its axis and flaring away from said ridge on opposite sides thereof

3. A spray coater as set forth in claim 1 in which said holding means comprises a spring pressed wheel means positioned to bear against and roll along said lance in opposed position to said two wheels.

4. A spray coater as set forth in claim 1 in which said holding means comprises two holding wheels positioned to bear against and roll upon said lance in spaced opposed positions to said first two wheels, said two holding wheels being floatingly mounted for movement toward and away from said lance, and spring means yieldably holding both of said holding wheels toward the lance.

This invention relates to centrifugal pipe casting apparatus. More particularly, this invention is a novel spray lance apparatus for applying a coating material uniformly to the inner surface of molds used in the centrifugal casting of pipe and other tubular products.

To prepare a mold for the casting of pipe it is necessary to first put a ceramic material on the inside of the mold which acts as a mold protective material as the molten pipe casting metal is fed into the mold. This ceramic material must be placed on the inside of the mold before each and every casting.

A current method of placing the protective ceramic material on the inside of the mold is to move a non-rotating spray lance longitudinally inside of a cylindrical metal mold which is rotated about its horizontal axis and which is usually at a high temperature. The spray lance is mounted on a movable carriage which usually rolls along tracks on a floor or other horizontal surface spaced substantially from the mold axis so that the non-rotatable spray lance can be moved longitudinally into and out of the turning mold. However, the lance must necessarily be small and quite long. Therefore since the space between the lance and the inside of the spinning mold is short any deviations in the track or any dirt on the track will be magnified in lateral movements of the free end of the lance and at times cause the lance to vibrate and touch the spinning mold. When this occurs the expensive lance may be destroyed and the mold damaged. Obviously, therefore, it is very important and desirable that the lance maintain a true position along the axis of the spinning mold and out of contact with the spinning mold.

It is an object of this invention, therefore, to provide the art with new and improved spray lance equipment which may be used even when the mold diameter is quite small and the lance quite long without running the risk of having the lance touch the spinning mold as it is spinning thereby preventing any chance of destroying the lance or severely damaging the inside of the mold.

Other advantages of this invention will become apparent by further reading of the description and drawings.

Briefly described, the invention as embodied in the preferred form herein fully disclosed, comprises a stationary support mounted adjacent one end of the horizontally positioned rotatably mounted cylindrical metal mold. The spray lance is mounted on the stationary support so as to be vertically adjustable along the support to match its level to that of the axis of the mold. The vertical adjustment of the spray lance may, for example, be accomplished by use of a hydraulic jack. The spray lance is then moved longitudinally into and along the axis of the bore of the cylindrical mold. This may be done by the use of a motor driven drive roller and idler rollers used to support and guide the spray lance on the stationary support during its longitudinal movement within the rotating mold. Tiltable means are also mounted on the stationary support angularly adjusting the lance to alignment with the axis of the cylindrical mold so that it may move therethrough without contact with the inside of the mold. This prevents the lance from becoming destroyed by contact with the inside of the mold and, of course, protects the inside of the mold from such contact.

In the drawings:

FIG. 1 is an elevational view partly in section showing one embodiment of the invention with the spray lance in position within the spinning mold applying a protective ceramic coating uniformly on the inside of the spinning mold;

FIG. 2 is an elevational view similar to FIG. 1 but showing the spray lance in retracted position outside of the spinning mold;

FIG. 3 is an elevational view on an enlarged scale and partly broken away showing the spray lance equipment itself;

FIG. 4 is a new taken along lines 4--4 of FIG. 3;

FIG. 5 is an elevational view of a second embodiment of the invention;

FIG. 6 is a view taken along line 6--6 of FIG. 5 and

FIG. 7 is a view taken along lines 7--7 of FIG. 5.

Referring to the drawings and particularly to FIG. 1, a housing 10 is shown enclosing a rotatable cylindrical mold 12. A pair of longitudinally spaced circumferential grooves 14 and 16 are provided on the cylindrical mold 12. Trunnions 18 and 20 fit within the grooves 14 and 16, respectively, and serve to support and rotate the cylindrical metal mold 12 about its axis. The trunnions 18 and 20 are driven by means of the electronically controlled variable speed motor 22 which drives the pulley 24 which in turn drives the belts 26 and thereby the shaft 28. The rotation of the shaft 28 causes the trunnions 18 and 20 to be moved thereby rotating the cylindrical mold 12.

The molten metal used in the pipe casting may be directed into the bore of the mold through pouring spout 30 which includes a funnel 32 extending into the part 34 at one end of the mold 12. Water pipe 36 containing a plurality of nozzles 38 is mounted in the housing below the cylindrical metal mold 12. High velocity jets of water are impinged on the mold 12. The high velocity of this water wipes away any steam that may be formed on the hot mold, and increases the rate of heat transfer, thus providing a highly efficient transfer of heat from the mold to the water.

The mold protecting ceramic material is applied to the inside of the spinning mold 12 prior to the pouring operation by means of a long thin spray lance 40 which has a spray nozzle 42 on its extremity. A flexible hose 44 is connected to the spray lance 40 and to a spray tank 46. The flow of ceramic material from the spray tank 46 through flexible hose 44 is controlled by suitable means such as the valve 48.

In accordance with this invention, the equipment for supporting and moving the spray lance 40 into and out of the cylindrical mold 12 while it sprays coating on the inside of the mold, is mounted on a stationary but vertically adjustable support 50 located adjacent one end of the housing 10. A horizontal spray lance mount compromising a sleeve 52 and a flat plate integrally mounted thereon provides a platform 54 for supporting a large portion of the spray lance equipment. The mount 52 with its platform 54 extending outwardly from one side of the stationary support 50 provides a means for supporting the spray lance equipment to one side of the stationary support 50 as shown in plan in FIG. 4.

The spray lance mount 52 is slidably mounted about the stationary support 50. Vertical adjustment of the mount 52 is accomplished by means of the hydraulic jack mechanism 56. Mechanism 56 is used to jack the spray lance mount 52 vertically along the stationary support 50. The adjusted position of mount 52 on the stationary support 50 is maintained by set screws 53 having lock nuts 55, or by other suitable clamping means.

A motor driven drive roller 58 (see FIG. 3) is mounted on the vertical plate-like support member 60 which is in turn carried on platform 54 of the spray lance mount 52. An idler roller 62 is supported by the idler roller support member 64. Idler roller 62 is horizontally spaced from the motor driven drive roller 58. The support 64 is pivotally mounted on the vertical member 60 by means of pivot connection 66. The pivotal position of the idler roller support member 64 is adjusted upwardly or downwardly relative to the platform 54 by means of the set screw 68 and nuts 70 and 72 interconnecting the platform 54 and the idler roller support 64.

A pair of idler rollers 74 and 76 are mounted above rollers 62 and 58 respectively in idler roller support 78. The idler rollers 74 and 76 are horizontally spaced from one another and idler roller mount 78 is vertically spaced from idler roller support 64 to provide space for the lance 40 between rollers 58 and 76 and between rollers 62 and 74, and to guide the lance 40 longitudinally along the axis of the cylindrical metal mold. The idler roller support 78 is pressed against the top of spray lance 40 by means of clamp screw 80 which is carried by support 60 and bears against support 78 between rollers 74 and 76.

As the spray lance 40 is moved into the housing 10 and into the spinning mold 12 its movement is limited by the switch 82 as best seen in FIG. 1. The length of spray lance 40 is chosen so that when the nozzle 42 is at the far end of the mold 12 the toggle arm 84 of switch 82 will fall off the back end of spray 40 and stop or reverse the motor 86 thereby stopping the drive wheel 58 or reversing its direction of rotation as is desired. As shown in FIG. 2 the backward movement of the spray lance 40 is limited by means of the stop switch 88. The toggle 90 of stop switch 88 falls over the shoulder of the spray lance 90 when it is in its most rearward position thereby stopping the movement of the drive roller 58.

If desired a heat shield 92 shown in FIG. 3 may be utilized to protect the tip 42 of the lance 40 from heat radiating from the mold 12 while the molten metal is being poured into the mold.

In the embodiment shown in FIGS. 5 through 7 the platform 94 is mounted on a cylindrical member 96 which telescopically fits within stationary support 98. The hydraulic jack 100 is used to operate the support 96 upwardly or downwardly to adjust the height of the spray lance. Once the proper height is obtained the clamps 102 and 104 are operated to clamp the mount 96 in position. As shown in FIG. 7 the idler roller support 64 is generally U-shaped and is connected to the vertical member 106 by means of the pivot connection 66. As previously explained in connection with the detailed description of the embodiment of FIGS. 1 through 4, the roller support 64 may have its angular position adjusted by means of the manipulation of nuts 70 and 72 on bolt 68. This permits the tilt of the spray lance 40 to be adjusted to make certain the tip 42 of the lance remains always on the center line of the mold and out of contact with the inside of the mold thus preventing damage to the spray lance and the inside of the mold.

As shown in FIG. 6 the idler roller support 78 extends downwardly from the cross piece 108. A clamp spring 110 controlled by bolt 112 resiliently biases the rollers 74 and 76 against the top of the spray lance 40. The ball 114 fitting within channel 116 on cross piece 108 along with the resiliency of the clamp spring 112 allows a certain amount of pivotal movement of the idler roller support 78 in response to pivotal movement of the idler roller support 64.

In operation when it is desired to apply the ceramic coating to the inside of the mold 12, the lance 40 is moved to approximately the position shown in FIG. 1. The movement of the lance into the mold 12 is stopped or reversed by the switch 82. The lance 40 is then slowly moved longitudinally along the mold 12 while the mold 12 is rotated about its axis. The spray is ejected from the nozzle 42 as the spray lance 40 is moved thereby placing a uniform coating on the inside of the mold itself. After the entire inside of the mold 12 has been coated with the ceramic material and the lance withdrawn to the position shown in FIG. 2 its backward movement is stopped by stop switch 88. The molten metal is then fed into the mold 12 through pouring spout 30 and the cast of the cylindrical pipe formed. After the cylindrical pipe has been formed then removed from the mold 12 the cycle may be repeated.

If for any reason the lance 40 should not move precisely along or parallel to the longitudinal axis or center line of the mold 12 this invention provides a means for adjusting the tilt angle of the lance 40. This is done merely by operating the nuts 70 and 72 on bolt 68 connected to idler roller support 64 thereby adjusting the position of idler roller 62. The provision of the resilient clamp spring 110 and the ball 114 in channel 116 causes the idler rollers 74 and 76 to be adjusted in response to adjustment of the idler roller 62. This, as previously stated, prevents damage to the spray lance and also prevents damage to the inside of the mold.

It will be seen that both forms of the invention as described eliminate the necessity for tracks or guides on the floor or other support at some distance laterally from the lance, and subject to the accumulation of dirt and obstructions, as well as to wear which contributes to the deviation of the lance from its desired path of movement, and, in the case of the dirt, and of some types of wear of the track or rollers, causing vibration of the lance such as may make it interfere with the rotating mold with the consequences heretofore explained. Instead, in the case of both forms of the invention a stationary support is provided carrying rollers which firmly and positively grip and position the lance by direct engagement with the lance, and by gripping it at a plurality of points on opposite sides and maintaining those points fixed during operation, positively guiding the lance along a straight line path of movement. No track is open for the collection of particles which could cause vibration as the lance moves forward, but instead only the clean lance is engaged by rollers and these rollers positively mounted upon a fixed support.

In each case the level of the lance is adjustable by means of a hydraulic jack or other suitable means after which it may be positively clamped with the desired level of adjustment so that when it is operated it will move precisely along the center line of the rotating mold and there will be the least possible likelihood of accidental engagement of the end of the lance with the mold.

In this respect, the difference between the two forms of the invention lies in the fact that in the form of FIGS. 1 to 4 inclusive there may be a somewhat greater range of vertical adjustment than in the form shown in FIGS. 5, 6 and 7. However, in the form shown in FIGS. 5, 6 and 7 the large cylindrical members which support the wheels that in turn carry the lance, are directly below these wheels and not offset to one side as in FIGS. 1 to 4 inclusive. For this reason the cylindrical supports of FIGS. 5, 6 and 7 may provide a structure a little less susceptible of vibration which might cause deviation of the lance from its intended path of movement.

In each case it will noted that the drive wheel is not adjustable relative to the platform on which the lance support and positioning wheels are mounted, but that the idler wheel 62 is adjustable vertically to any desired fixed position relative to such support, and, with the fixed drive wheel, determine the angle at which the lance will be maintained relative to the support.

In order that the adjustment of a single idler wheel such as 62 might serve to adjust the angle of the lance, and yet provide for a positive holding force to maintain the lance in engagement with the drive wheel and the idler 62, two other idler wheels are provided above the lance in each case, and these are mounted on a floating support member 78 at spaced apart positions from one another and downwardly biased by means of a spring whose tension is adjustable. By this means the lance is always held tightly against the drive wheel 58 and the idler wheel 62 with a positive balanced pressure which is, however, adjustable by means of adjustment of spring 110.

While the cross sectional shape of the lance may be any one of a number of shapes which may be desired, that which is illustrated is a square cross section as shown in FIG. 6 and the wheels, in order to appropriately clamp such a shape of lance, are made with their grooves V-shaped, preferably at a slightly wider angle than the rectangular corner of the lance, so that the engagement be directly on the upper and lower corners of the cross section of the lance and the lance, by engagement with the apexes of the V-shaped grooves in the wheels, will be held precisely in position and alignment as it moves forward and backward in its travel into and out of the mold.