A – The stem/fork packing is isolated from the bonnet seal arrangement and is live-loaded. Belleville springs on the packing gland bolts self-adjust to maintain constant packing load regardless of thermal cycling. The design reduces the potential for packing leaks.

 

B – Belleville springs accommodate for thermal expansion of the choke’s internal components. During thermal cycling in startup or normal operation, the Belleville springs self-adjust to maintain an ideal contact load between the control discs. 

 

This self-adjustment eliminates the possibility of lockup, regardless of process temperature or pressure (with the material limits). The internal springs also provide a constant load to prevent external leakage trough the bonnet packing.

 

C – The control discs are designed to provide precise control so that production rates are controlled with a high degree of accuracy. The discs also provide long-term erosion resistance in high-velocity, saturated steam service. 

 

Various orifice shapes, size and configurations are available for a wide range of production rates and control requirements. The steam choke can easily be retrofitted with new discs if well conditions or production rates change over time.