Pipe coupling torque control

Abstract

A fluid powered pipe tong fluid supply has a shunt that fluidly connects the tong input fluid line to the tong output fluid line. A flow control valve is installed in the shunt and is open when pipe joint make-up begins. The valve is slowly closed and the resulting fluid power made available to the tong causes it to make the low-resistance turns required of the pipe during the thread run. As the valve continues to close, the resulting pipe turn increases the resistance and causes the tong motor to demand more pressure, to achieve more turn. Torque demand continues to develop as the valve continues to close. Options include computer control, a graph reader to direct the computer, a recorder, a manually set by-pass relief valve to parallel the flow control valve as a secondary pressure limit assurance.

1 . A threaded pipe connecting system for use in manipulation of connection functions for the assembly of pipe strings in wells, and bucking units in shops, the system comprising:
 a) a power tong with provisions to measure output torque, rotational speed, and amount of pipe rotation from a preselected reference point;   b) a source of fluid power, with fluid controls, to deliver fluid power to said tong;   c) a valve controlled shunt arranged to drain any amount of available fluid from a circuit delivering fluid from said source to said tong; and   d) said valve, adjustable over a preselected range of flow.   
   
   
       2 . A threaded pipe connecting system according to  claim 1  wherein said output torque is measured as the reaction torque in the tong body. 
   
   
       3 . A threaded pipe connecting system according to  claim 2  wherein said reaction torque is measured as a function of force required to prevent rotation of said tong about said pipe string. 
   
   
       4 . A threaded pipe connecting system according to  claim 1  wherein said torque is measured as a function of fluid pressure differential supplied to a motor driving said tong. 
   
   
       5 . A threaded pipe connecting system according to  claim 1  wherein a computer is supplied and said valve is controlled by said computer programmed to receive at least data related to said torque and direct said valve to achieve a preselected condition. 
   
   
       6 . A threaded pipe connecting system according to  claim 5  wherein a graph reader is supplied and said computer receives input data from said graph reader and controls said valve to achieve the conditions indicated by graphs. 
   
   
       7 . A threaded pipe connecting system according to  claim 1  wherein a recorder is provided to record at least the turn and torque experience of each connection. 
   
   
       8 . A method for controlling the torque applied to pipe connections when assembling pipe strings in wells, and bucking units in shops, the method comprising at least the following steps:
 a) provide power tongs and fluid power to drive said power tongs to assemble pipe;   b) provide fluid circuitry to drain away said fluid power available to limit tong torque;   c) decrease the drain rate until the tongs rotate enough for the connection to accept a pre-selected torque.   
   
   
       9 . The method according to  claim 8  wherein the torque and turn experience of the pipe connections are recorded on transportable medium. 
   
   
       10 . The method according to  claim 8  wherein a graph reader, using a graph related to required limits of torque versus turns for the connection being processed, in conjunction with a controlling computer, automatically reacts with tong controls to stop processing the connection when conditions required by said graph are not met. 
   
   
       11 . A method for controlling the torque applied to pipe connections when assembling pipe strings in wells, and bucking units in shops, the method comprising at least the following steps:
 a) provide power tongs and fluid power to drive said power tongs to assemble pipe;   b) provide fluid circuitry to drain away said fluid power available to limit tong torque;   c) adjust the rate of said drain to provide enough fluid pressure to rotate said tongs to provide the connection a hand-tight condition; and   d) decrease the drain rate until the tongs rotate enough for the connection to accept a pre selected torque.   
   
   
       12 . The method according to  claim 11  wherein the torque and turn experience of the pipe connections are recorded on transportable medium. 
   
   
       13 . The method according to  claim 11  wherein a graph reader, using a graph related to required limits of torque versus turns for the connection being processed, in conjunction with a controlling computer, automatically reacts with tong controls to stop processing the connection when conditions required by said graph are not met. 
   
   
       14 . The method according to  claim 11  wherein at least two parameters, from which tong torque can be derived, are recorded. 
   
   
       15 . A threaded pipe connecting system for use in manipulation of connection functions for the assembly of pipe strings in wells, and bucking units in shops, the system comprising:
 a) a power tong with provisions to measure output torque, rotational speed, and amount of pipe rotation from a preselected reference point;   b) a source of fluid power, with fluid controls, to deliver fluid power to said tong;   c) a valve controlled shunt arranged to drain any amount of available fluid from a circuit delivering fluid from said source to said tong;   d) said valve, adjustable over a preselected range of flow; and   e) provisions to measure at least two of said output torque, rotational speed, and amount of pipe rotation from a preselected reference point.   
   
   
       16 . A threaded pipe connecting system according to  claim 15  wherein said output torque is measured as the reaction torque in the tong body. 
   
   
       17 . A threaded pipe connecting system according to  claim 16  wherein said reaction torque is measured as a function of force required to prevent rotation of said tong about said pipe string. 
   
   
       18 . A threaded pipe connecting system according to  claim 15  wherein said torque is measured as a function of fluid pressure differential supplied to a motor driving said tong. 
   
   
       19 . A threaded pipe connecting system according to  claim 15  wherein a computer is supplied and said valve is controlled by said computer programmed to receive at least data related to said torque and direct said valve to achieve a preselected condition. 
   
   
       20 . A threaded pipe connecting system according to  claim 19  wherein a graph reader is supplied and said computer receives input data from said graph reader and controls said valve to achieve the conditions indicated by graphs. 
   
   
       21 . A threaded pipe connecting system according to  claim 15  wherein a recorder is provided to record at least the turn and torque experience of each connection.