A New Cam-Set Line Blind SAGD Throttling Solution


A Canadian oil sands facility was using globe valves on 8, six-inch injection lines to throttle and control the injection of flocculent to a thickener tank below.

Due to the persistently erosive nature of the line media that would destroy the globe valves involved in flocculent injection every 2-3 months, the facility decided to use lower cost orifice plates for throttling, alongside a gate valve for isolation.

The placement of the drop-down lines at the facility required maintenance personnel to work over a railing in order to access the current valves and proposed orifice plates.

A conventional orifice plate would be difficult to change in this location; it was important to the facility that they source a low-maintenance, quick-changeover solution.

conventional orifice plate
A conventional orifice plate
Schuf cam set line blind
The SchuF Cam-Set line blind can be modified to include orifice plates on both sides of the spectacle plate


An instrumentation engineer reached out in search of a solution and Armour Valve and SchuF suggested a SchuF Cam-Set line blind customized with orifice plates.

While not traditionally used for throttling, a Cam-Set line blind can be equipped with orifice plates on each end of the spectacle plate. As one orifice plate wears out, operators can isolate the line and quickly swing the blind to move the second orifice plate into position. The worn plate can then be replaced in-line.

The time for two maintenance personnel to replace a single conventional orifice plate in the hard-to-reach location was estimated at 60 minutes. A modified SchuF line blind can be maintained by a single person in as little as 5 minutes.


SchuF Cam-Set line blinds were installed on all 8 injection lines where they have helped to greatly reduce maintenance time and replacement costs at the facility.

Previously, two maintenance personnel would spend approximately 3 to 4 hours to replace each of the globe valves.

Maintenance of a SchuF line blind customized with orifice plates can be performed by a single person in as little as 5 minutes.

Comparative Maintenance Requirements

Throttling OptionWorkersEstimated Service Time Per Worker
Original Globe Valve224-32 hrs
Conventional Orifice Plate28 hrs
Modified Cam-set Line Blinds1<1 hr
The time savings when changing all 8 lines provided by different throttling options