Abstract:
A connector in a network of lubrication pipes is provided with a valve that automatically closes off the connector whenever one of the pipes is withdrawn following an incident. Lubricant leaks are thus avoided. The valve plug is cylindrical-conical and it is fitted with a needle.

Description:
BACKGROUND OF THE INVENTION 
   (1) Field of the Invention 
   The purpose of this invention is a lubrication cut-off device. 
   (2) Description of Related Art 
   Some machine bearing blocks are lubricated through pipe networks comprising a pump and pipes carrying the lubrication to each bearing block. The ends of the pipes are attached to bearing block supports through collars or similar devices. However, it is possible that the bearing block supports may break or move in another manner, particularly if an out-of-balance mass appears on the shaft supported by the bearing block. The pipes are then torn off from their connectors to the rest of the network and the lubricant spreads in the machine causing various damage, and possibly igniting if it comes into contact with burning regions; furthermore, this lubrication is no longer available for other bearing blocks that may become dry. 
   The purpose of this invention is a lubrication cut-off device under these circumstances, the effect of which is to cut off the arrival of lubricant at the bearing block for which the supply pipes were torn off from the network. 
   BRIEF SUMMARY OF THE INVENTION 
   In its most general form, the invention relates to a lubrication cut-off device comprising a lubricant pipe that may be torn off, a pipe connector into which an end piece of the said pipe is pushed in, a valve housed in the connector and pushed into a seating in which it closes off the connector through the end piece, and possibly a means of pushing the valve plug into contact with the seating. Furthermore, the valve plug comprises a cylindrical body sliding in a housing of the connector, a conical thrust facet in contact with the seating and a thrust needle valve in contact with the end piece, the body being perforated. 
   The valve plug thus designed is subjected to a sliding movement when it closes, and has a uniform shaped cross section for passage of the lubricant that is invariable with time when it is open, since it is held in place laterally in the pipe. Therefore, the lubricant flows without any variation in the flow or pressure loss. Furthermore, there is a guaranteed and known thrust force applied by the lubricant when the valve plug closes, so that the closing spring can confidently be eliminated. 
   The following describes specific embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following figures should be read in conjunction with this text: 
       FIG. 1  is a partial view of a lubrication device equipped with an embodiment according to the invention; 
       FIG. 2  is an enlargement of  FIG. 1 ; 
       FIG. 3  is a view of the cut-off device in the state in which the pipe is torn off from the connector; 
     and  FIG. 4  illustrates another embodiment of this system. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The lubrication network in  FIGS. 1 and 2  includes particularly a general supply pipe  1  that ends at a connector  2  that connects it to a lubrication pipe  3 , that transfers lubricant to a front bearing block  4  in a shaft line, close to a gas turbine blower  5 , and that also includes a fork  6  towards a second bearing block  7  slightly behind the first bearing block; in this case, the connector  2  also comprises a second lubrication pipe  8  leading to a third bearing block  9  even further behind the others. In general, the lubrication pipes are fitted with a sprayer nozzle  10  at their end facing the bearing block, and close to this position they are connected to a structure  11  of the support bearing block through a collar, an attachment tab  12  or any other means. In this case, the pipe  3  is still connected through its opposite end close to connector  2 , to the structure  11  through another attachment tab  13 , and in fact a connection tube  14  to the pipe  3  actually supports an end piece  15  pressed into a drilling  16  in the connector  2  so that the oil from pipe  1  passing through connector  2  then passes into the tube  14  and then the pipe  3 . This double support layout of the lubrication pipe  3  and the separate connection tube  14  does not in any way change the existing problems; the tube  3  can be entrained if the support  11  is deformed, and the continuity of the lubrication network disappears as soon as the pipe  3  is torn off from tube  14 , or if it is torn off from the connector  2 . 
   A valve plug  17  forming part of the invention becomes useful in this rupture situation. As shown in  FIG. 3 , it comprises a cylindrical body  18  at the front, with a front face  19  touching the end piece  15 , and which slides in a support ring  20  at the bottom of the drilling  16 ; a cylindrical base  21  near the back and that slides in a cylindrical housing  22  in connector  2 ; and a conical face  23  that connects the body  18  to the base  21 . Furthermore, the body  17  is hollowed out over its entire length, opening up towards the front of tube  14  and sideways through drillings  24 ; and the base  21  is fitted with a compression spring  26  behind a reception housing  22 , the spring extending as far as the bottom of the housing  22 . 
   Under normal conditions, oil coming out of pipe  1  enters the third lubrication pipe  8 , going around the cylindrical body  18  and the pipe  3 , through the tube  14 , passing through the orifices  24  and the recess in the body  18 . However, if the pipe  3  is moved, the spring  26  coaxial with the valve plug  17  and the tube  14  is then free to expand and to push the tube, forcing the end piece  15  out of the drilling  16  if the tube  14  remained in place. The conical face  23  then is forced into contact with seating  27  with a shape corresponding to the housing  22 , and this contact causes a seal, the housing  22  then being closed by the valve plug  17 . Bearing blocks  4 ,  7  and  9  are then no longer supplied through the network, but sufficient static lubrication remains until the shaft is stopped. 
   The embodiment shown in  FIG. 4  has some elements that are already in the previous figures. 
   A connector  30  is placed between a supply pipe  31  and two lubrication pipes  32  and  33 , the first of which can be torn off. The connector contains a cylindrical housing  35  of the valve plug  45 . The housing  35  connects the supply pipe  31  to an orifice  37  that opens up into another housing  36  at the connection of the lubrication pipes  32  and  33 . The orifice  37  is surrounded by a conical seating  38  opening up into the housing  35 . The pipe  32  comprises an end piece  39 , the end of which supports a lip  40  projecting into the other housing  36  and in front of orifice  37 ; the lip  40  extends around part of the periphery turn in order to avoid excessively restricting the lubricant flow. The shape of the valve plug  45  is complex and similar to that shown in  FIGS. 1 and 2 , since it comprises a cylindrical body  46  (at the back in this case), a conical face  47  (in front of the body  46 ) and a needle valve  48  extending the conical face  47  forwards and that touches the distribution pipe  32  and more precisely its lip  40 . 
   The needle valve  48  passes through the communication orifice  37  of the housings  35  and  36 , and the body  46  also has recesses, in this case axial grooves  49  at its periphery. Oil forced out of the supply pipe  31  into the housing  35  passes through the connector  30 , passing through the grooves  49  and passing in front of the conical face  47  and the needle valve  48  before entering the housing  36  and being distributed into pipes  32  and  33 . If pipe  32  is torn off, the lip  40  disappears and the oil pressure pushes the valve plug  45  until the conical face  47  touches the seating  38  and interrupts the communication through the connector  30 . 
   The section of the grooves  49  and the orifices  24  precisely determines the characteristics (flow and head loss) of the lubricant flow through the valve plug  17  or  45  in the open state. Closing is fast and regular. No spring is necessary in this case, in which the valve is coaxial with the flow. 
   The valve plug may have any arbitrary displacement direction with respect to the penetration direction of the lubrication pipe with which it cooperates in the pipe connector; in particular, the directions may be identical or may intersect.