Coiled tubing injector with flow limiter

Abstract

A flow-limiting device is placed in a hydraulic fluid circuit between a hydraulic pump of, for example, a power pack, and a motor of a coiled tubing injector. The flow-limiting device allows hydraulic fluid to flow through the circuit, but limits the rate of flow in order to avoid thermal damage to the motor.

What is claimed is:  
     
         1 . A coiled tubing injector system, comprising: 
 a coiled tubing injector having a pair of opposing continuous chains rotated by power supplied from at least one hydraulic motor, the motor being connected to a hydraulic power circuit for receiving a flow of hydraulic fluid under pressure; and    a flow limiting device coupled in the hydraulic circuit for preventing hydraulic fluid from flowing into the motor at rates in excess of a predetermined rate.    
     
     
         2 . The coiled tubing injector system of  claim 1 , wherein the flow limiting device is mounted on the coiled tubing injector.  
     
     
         3 . The coiled tubing injector system of  claim 1 , in combination with a power pack having a hydraulic pumping system for pumping hydraulic fluid in the hydraulic power circuit.  
     
     
         4 . The coiled tubing injector system of  claim 3 , wherein the flow limiting device is mounted to the power pack.  
     
     
         5 . The coiled tubing injector system of  claim 1 , wherein the hydraulic motor is a high speed, low torque motor, and wherein the motor and the chains are coupled through a speed reduction gear box.  
     
     
         6 . A coiled tubing injector, comprising: 
 a pair of opposing continuous chains rotated by power supplied from at least one hydraulic motor, the motor being connected to a hydraulic power circuit for receiving a flow of hydraulic fluid under pressure when coupled with a hydraulic pumping system; and    a flow limiting device coupled in the hydraulic circuit for preventing hydraulic fluid from flowing into the motor at rates in excess of a predetermined rate.    
     
     
         7 . The coiled tubing injector of  claim 6 , wherein the hydraulic motor is a high speed, low torque motor, and wherein the motor and the chains are coupled through a speed reduction gear box.  
     
     
         8 . In a coiled tubing injector, the injector having opposing continuous chains rotated by power supplied from at least one hydraulic motor mounted on the injector, the motor being connected to a hydraulic power circuit for receiving a flow of hydraulic fluid under pressure, a method comprising: 
 coupling a hydraulic pumping system to the hydraulic power circuit; and    limiting the maximum flow rate of the hydraulic fluid delivered to the motor by a flow limiting device coupled in the hydraulic circuit.    
     
     
         9 . The method of  claim 9 , wherein the flow limiting device is mounted on the coiled tubing injector.