Trim design and salient features of chokes
We have developed a variety of trim designs to cater to a wide range of applications, and these have been field-proven from various installations all over the globe.
Trim design
Positive choke
Control element not available to vary orifice size. Need to change choke beans by removing hammer union type bonnet if different flow conditions required. The orifice diameters of these beans are specified in 1/64" diametrical increments i.e. 5/64", 32/64", 64/64", 124/64" etc.
Needle & seat
The control element in the form of the needle is provided to vary orifice size by changing the position of needle. The simplest design of adjustable chokes available in the market, but have proven themselves in the toughest applications.
Microform trim
Specialized trim for gas injection and gas lift applications. Low Cv profile with microform cage enables fine regulation and prevents high noise and vibrations by breaking flow into a number of small streams.
Internal plug with cage & External sleeve with cage: single-stage
Cage type trim design makes use of 4 x 4 holes geometry with the principle of self-impingement using diametrically opposed flow jets to dissipate the kinetic energy of fluid after throttling at the center of the cage, contains the high energy fluid within the replaceable trim components, and protects the choke body. 4 x 4 holes geometry gives unbeatable rangeability and turns down ratios for cage type trims.
The pressure is dropped in one stage only.
The control element, a plug that moves inside the cage, vis-a-vis plug, and cage, or a sleeve that moves outside the cage in case of external sleeve design to vary the orifice size.
Internal plug with cage: multi-stage (Concentric Cage)
The cage assembly consists of 2 to 5 individual concentric cages one fitted over the other, with drilled holes to form tortuous paths for passing fluid to drop the pressure in a number of stages. The control element moves inside this cage assembly to vary the orifice size.
This design carries overall advantages of a traditional plug and cage style single stage trim and adds multiple pressure drop stages to give exceptionally good performances in high-pressure drop applications to reduce or even eliminate excessive noise, cavitation, vibration & erosion.
Velocity control disc type - multi-stage
Specialized multistage trims for high flow and very high-pressure drop applications. Torturous paths are machined on individual disks which are then stacked one over another to form a flow cage assembly.
Pressure drop stages range from 5 to 9. Developed to provide a high number of pressure drop stages with low-pressure recovery within the flow stream to minimize the potential for excessive noise, cavitation, vibration, and erosion.
Single path multi-stage
This design makes use of a contoured plug that moves inside a sleeve with multiple throttling surfaces build into it. The fluid is throttled between the plug contours and the throttling surfaces of the sleeve. This multistage pressure drop trim offers a unique advantage because of its suitability for use in contaminated services and ability to pass solid particles up to certain sizes, without chances of getting plugged. The number of pressure stages available is 2 to 7.
Salient features of chokes
