Abstract:
A spinning wash nozzle assembly having a fluid brake pump within the rotating spinner housing. The fluid pump has a sump which is also within the rotating spinner housing such that centrifical forces acting on the fluid tend to separate the heavier fluid from any air within the sump. As a result, only the fluid is drawn into the pump as opposed to fluid and air. This avoids undesirable effects on the pump from air being drawn therein.

Description:
This application claims benefit of provisional application Ser. Nos. 60/051,193 filed Jun. 30, 1997 and 60/057,301 filed Sep. 2, 1997. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a spinning wash nozzle assembly and in particular to a nozzle assembly having a liquid pump brake contained within a rotating spinner housing such that centrifugal forces separate the pumping liquid from air contained within the liquid to ensure that only the liquid is drawn into the pump. 
     A spinning wash nozzle assembly is known in the prior art from U.S. Pat. No. 5,020,556. This spinning nozzle comprises two main parts: 1) a rotating spinner head and shaft and, 2) a stationary housing providing bearing support for the rotating spinner head and shaft. Water enters the nozzle assembly through a fitting fastened to a support structure. A plurality of nozzles attached to the spinner head provide outlets for the pressurized water. The nozzles are set at an angle relative to the rotational axis of the spinner head such that the reaction forces from the water jets cause the spinner head to rotate about its axis. The rotational speed of the spinner head is controlled by a fixed displacement internal/external gear oil pump acting as a braking device by adjusting pump discharge flow pressure. The braking pump in this prior patent includes an inner gear coupled to the spinner head shaft for rotation therewith and an outer gear fixed to the housing. The housing further contains an oil sump for oil pumped by the braking pump. One problem associated with such a braking pump is the undesirable effect on the pump of air mixed within the oil. 
     The present invention provides a spinning wash nozzle assembly in which the braking pump as well as the fluid or oil sump for the pump are placed in the rotating spinner head and as opposed to the stationary housing as shown in the above referenced patent. This results in a simpler and a less expensive construction which has a further functional advantage. Due to the centrifugal effect on the rotating oil pump, any air present in the oil separates from the oil. The heavier oil moves radially outward while the lighter air moves radially inward, toward the axis. As a result, only oil is available at the pump inlet such that the oil drawn into the pump is free of air. 
     The pump is also configured with the inner gear held stationary while the outer gear is rotated. The discharge pressure of the oil pump is controlled by a pressure-regulating valve. The valve is biased either by a spring or by a centrifugally-generated force. In addition, temperature compensation can be provided through a bimetallic spring which produces a spring-force variable in relation to oil temperature. 
    
    
     Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of a spinning wash nozzle assembly of the present invention; 
     FIG. 2 is an axial view of the spinner head showing the oil sump and oil circulating passages of the braking pump; 
     FIG. 3 is a sectional view of an alternative embodiment of a spinning wash nozzle assembly having a centrifugally controlled regulating valve; 
     FIG. 4 is a fragmentary sectional view of an alternative embodiment of a braking pump pressure regulating valve showing a temperature compensating valve; 
     FIG. 5 is a sectional view of an alternative embodiment of the spinning wash nozzle assembly utilizing a commercial rotary union for mounting the rotating spinner head; 
     FIG. 6 is an axial view of another embodiment of the spinner wash nozzle assembly of the present invention; 
     FIG. 7 is a sectional view of an oil pressure check valve for speed control of the spinner wash nozzle assembly shown in FIG. 6; and 
     FIG. 8 is a sectional view of a back flow pressure relief valve. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The spinning wash nozzle assembly of the present invention is shown in FIG.  1  and designated generally at  10 . The assembly  10  consists of two main parts, a stationary first part or shaft  12  and a rotating spinner housing  14 . The stationary shaft  12  is hollow and has an external threaded portion  16  to mount the assembly to a support structure. 
     The spinner housing includes a spinner head  18 , a cover plate  20 , a spacer plate  22  therebetween, and a spinner shaft  24  to rotatably mount the spinner housing to the stationary shaft  12 . The spinner shaft  24  is disposed within the stationary shaft  12  and is supported by a pair of needle bearings  26 . Water flows through the hollow spinner shaft  24  to four threaded, radial passages  28 , only two of which are shown. Standard tube fittings  30  are threaded into the passages  28 . A nozzle tube  32  with a nozzle  34  and a tapered sleeve  36  inserted therein are secured to the fitting  30  by a connector nut  38 . Rotating motion of the spinner housing is achieved setting the nozzle tubes  32  in a position angular to the rotational axis  40  of the assembly. Reactional forces from the high pressure water jets create a moment that causes the spinner housing to rotate. 
     Two seals  42  disposed within grooves in the spinner shaft  24  and a vented groove  44  therebetween prevents high-pressure water from entering the oil-filled parts of the spinner. A vent passage  45  is provided to vent the groove  44 . Lip seal  46  is pressed into the cover  20  to seal the oil filled pump cavity. 
     The axial force component from the water jet reaction force is taken to the stationary shaft  12  by needle-thrust bearing  48 . Movement in the opposite axial direction is prevented by retaining ring  50  inserted in a groove formed in the stationary shaft  12 . 
     An oil pump  52  in the spinner housing  14  is used as a brake to slow the spinner housing to a desired rotational speed. The pump operates in an oil-filled pocket formed in the cover  20  and consists of an outer gear  54 , which in this case is the driving gear, and a stationary gear  56 . The inner gear  56  is held stationary to the stationary shaft  12  by a key  58 . The outer driving gear  54  is an internal gear while the inner gear  56  is an external gear. A typical arrangement for a gear pump uses the inner gear as the driving gear. In the present invention, it is the outer gear that is the driving gear. This inverted arrangement is advantageous because it increases the speed of the pump and allows for the use of a smaller displacement pump. 
     The spacer plate  22  between the spinner head  18  and the cover  20  separates the oil pump from the oil sump  60  formed in the spinner head  18 . The plate  22  also includes the inlet and outlet ports for the oil pump. Oil from the sump  60  enters the pump through the inlet port and leaves pressurized through the outlet port to the passage  62  leading to the pressure regulating valve  64  as shown in FIG.  2 . This valve comprises of ball  66  and a bias spring  68  thrusting the ball against aperture  70  formed in a wall separating the sump  60  and the pump outlet passage  62 . A threaded plug  72  sealed in the valve bore  74  is used to adjust the spring force for controlling the oil outlet pressure from the pump. The pump pressure determines the braking effort of the pump which determines the rotating speed of the spinner housing. 
     Because the oil sump  60  is rotating with the spinner housing, the centrifugal forces on the oil will cause the oil to move radially outward from the axis  40 . The lighter air within the sump will be forced radially inward. By locating the pump inlet at a radial outward location, only oil is drawn into the pump. As a result, the undesired effects of air within the pump are eliminated. 
     An alternative embodiment of the invention is shown in FIG. 3 which features a closed-loop speed control system that should make all infield adjustment unnecessary. The spinner housing  76  includes a spinner head  78  and is mounted on a spinner shaft  24 . The spinner head contains an oil passage  80  from the pump outlet  82 . The passage  80  ends in a port  84  through which oil from the pump outlet must flow. A flow control valve spool  86  assumes a position which fully or partially covers the port  84 . The spool  86  is positioned between a spring  88  and centrifugal weights  90 . The centrifugal weights  90  are pivotally mounted to the spinner headcap  79  by pins  92 . The weights create a force proportional to the spinner turning speed. The force of the weights thrust on one end of the spool  86  and are opposed to the force from the spring  88 . The spool assumes the position where the two opposing forces are in equilibrium. The oil flow through the port  84  is dependent on the size of the uncovered portion of the port, pump speed and the discharge pressure of the pump. Desired speed can be attained by adjusting the spring force of the spring  88 . This is done by turning the spring retaining screw  94  and locking it in a new position by the lock nut  96 . Spinner headcap  79  is bolted to the front face of spinner head  78 . 
     This speed control system is not as sensitive to part inaccuracies and environmental variations such as temperature. For example, if the pump becomes warm causing the discharge pressure to drop, the reduction in a braking effort will speed up the spinner. This results in adjustment of the spool position to reduce the size of the port  84 . This causes the pressure in the pump to increase and increases the breaking effort to restore the original spinner velocity. 
     With reference to FIG. 4, an alternative embodiment of the oil pump pressure regulating valve is shown. When the temperature of the oil falls and its viscosity increases, the oil shear losses also increase, causing the spinner to turn at a slower speed. A thermostatic element acting on the pressure relief valve reduces the force acting on ball  66  which lowers the pump pressure causing the spinner to turn faster. A generally U-shaped spring  100  is used to hold a ball  66  into the pump outlet port  102  in the spacer plate  22 . The spring force is in part controlled by the threaded plug  104 . Temperature compensation is made by a bimetallic spring  100 . The spring will change its force in proportion to temperature changes. 
     With reference to FIG. 5, yet another embodiment of the spinner wash nozzle assembly is shown. Components in the assembly  110  that are similar to components in the assembly  10  are given the same reference numeral plus  100 . The assembly  110 , like assembly  10 , includes an oil pump  152  within the rotating spinner housing  114 . The oil pump includes an outer gear  154  and an inner gear  156 . The pump further includes a sump  160 . 
     The rotating spinner housing  114  is mounted to the rotating union output shaft  117  of a commercially available rotary union  119 . The union  119  includes a housing  121  with a water inlet  123 . Water flows through the hollow rotating output shaft  117  and enters the spinner housing  114 . 
     A stationary shaft  125  is attached to the union housing  121  at the housing end  127 . The shaft extends through the union and into the rotating spinner housing. The shaft is coupled to the pump inner gear  156  by a key  129 . The shaft holds the inner gear stationary. Two seals  131  are placed in grooves in the shaft  125  and a vented groove  133  is placed therebetween to prevent high pressure water from entering into the pump cavity. The seals  131  run against the inner surface of a sleeve  135  pressed into the body of the spinner housing. The shaft  125  is supported by a needle bearing  137  pressed into the cover  120 . 
     The spinner housing is secured to the output shaft  117  of the union by a retaining ring  139 . The rotary union  119  provides rotary support for the output shaft  117  and, by virtue of its commercial availability, reduces the overall cost of the wash nozzle assembly. Like the embodiment shown in FIG. 1, the oil pump and its sump are located in the rotating spinner housing such that the oil and air are separated and only oil is drawn into the pump. 
     FIG. 6 shows yet another embodiment of the spinner of the present invention which is constructed in such a manner to provide for relatively easy assembly. Components of the assembly  210  that are similar to components in assembly  10  are given the same reference numeral plus  200 . The assembly  210 , like assembly  10 , includes an oil pump  252  within the rotator spinner housing  214 . The gerotor type oil pump includes an outer gear  254  and an inner gear  256 . 
     The rotating spinner housing  214  is coupled to the rotating shaft  224  which is mounted into a fixed shaft  213  upon needle bearings  226 . 
     A spinner port plate  222  is provided, adjacent to the gears  254  and  256 , which contains the inlet and outlet openings to the pump. On the opposite side of the pump gears is a plate  203  which bears against the cover  220  closing the spinner housing  214 . The cover  220  is retained axially in place on the spinner housing by a tapered snap ring  217 . 
     A lip seal  246  is provided between the cover  220  and the stationary shaft  212 . A thrust bearing  207  is positioned between two thrust washers  205  and are retained against a ledge on the stationary shaft  212  by a snap ring  219 . A shoulder  221  of the cover  220  bears against one of the thrust washers  205  to carry thrust load from the spinner housing to the stationary shaft  212 . 
     A face seal  209  is provided at the interface between the rotating shaft  224  and the fixed shaft  212 . This prevents water from entering into the needle bearings and ultimately into the oil pump. A vent port  215  is provided to allow any high pressure water that has passed the face seal to drain rather then entering past the lip seal  213  into the needle bearings. 
     The pressure control valve shown in FIG. 7 controls the pump output pressure and thus controls the speed of the spinning nozzle assembly. The port plate  222  contains a pump high pressure outlet port  223  which is closed by a ball  266 . A spring  268  bears against the ball to hold it in a closed position against the port  223 . The spring force is adjustable by a threaded plug  272 . A back flow pressure relief valve  301  is shown in FIG.  8 . The port  302  is on the suction side of the oil pump during normal operation. The port  304  is on the high pressure side of the oil pump. During normal operation of the pump, the ball  306  closes the port  302  and prevents oil flow through the valve. However, in the event the spinner is manually rotated in the opposite direction from normal operation, the suction side of the pump will be pressurized. The valve  301  is provided to relieve pressure on the suction side of the pump. If not relieved, the pressure can blow out the seals in the spinner assembly, which are designed to be on the suction side of the pump. The spring  308  provides a relatively low force to be overcome by the oil pressure such that the pressure is relieved at a low level. Thus there can be no pressure build up in the oil sump and in the area connected thereto thereby preventing the oil seals from being blown out. 
     The spinner assembly  210  is disassembled by removal of the snap ring  217  allowing the spinner housing  214  to be removed and access gained to the internal components of the spinner assembly. The spinner housing  214  includes the oil sump for the pump, thus providing the advantages of the present invention in that the oil sump is rotating, enabling separation of oil and air. 
     It is to be understood that the invention is not limited to the exact construction illustrated and described above, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.