ROD FUNCTIONS – BASIC OPERATION

All the Rod Locks models operate in basically the same way.  The main difference is some models have a second set of rams which provide the ability to seal off well bore fluids if the rod string in on present, what is termed as a blind ram on true BOP’s. Operation of the rod lock serves three functions typically involving the following steps.

FLOW TEEFirst and primary function is as an upstream manifold (composite flow tee): During pumping operation the well bore fluid would pass through the bottom connection (attached to the wellhead) into the rod lock.  The fluid would pass by the open rams and into the main diverting chamber.  Components attached to the top connection of the rod lock, usually a PC Pump Drive Head, shall prevent fluid from escaping into the environment.  The fluid would then be forced to travel through the side ports into a system of piping determined by the customer.

LOCKOUT CLAMPThe second function (lock out clamp) is if you are required to install, remove or service any components (pump drive head, etc.) above the rod lock you typically are required to support the weight of the rod string, which runs through the rod lock.  The rod lock acts as a clamping device to hold the position of the rod string when the normal support method has been removed.  This is accomplished by manually screw in the two large rods on either end which clamp rams against the rod string, holding it from moving.

BOPThe third function to this component is that the clamping function through design also acts to isolate the well and preventing well bore fluids from escaping from the production tubing when the other components above the rod lock have been removed and no longer serve this function.  The clamps have a special seal that prevents potential well fluids from migrating pass the rod string, essentially acting as a BOP (Blow Out Preventer Pipe Rams), as without this set up the well may be open to atmosphere.  This function is only a safety feature because typical these components are used on non-free flowing wells.  When the downhole PC Pump is not turning there is no pressure, but should the well pressurize for some reason this would prevent fluid escaping into the environment.

Operating Parameters,

FLOW TEE OR BOPMaximum Safe Working Pressure: 2900 psi (was 3000 psi as shown on brochures), this pressure was chosen to maintain a Pressure Directive category II compliance, above this pressure would move the product into cat. III.

Typically working Pressure: up to 1000 psi,

Temperature: ambient

Operation: manual application

LOCKOUT CLAMPMaximum polish rod (string) weight: varies from model to model most are 25 000 pounds