Circuit Sentry Cartridge: The difference in flow limiting valves!

Accurate The unique cartridge design demands that all flow pass through the control orifice giving complete and accurate flow control ±5%. Non-Clogging The Circuit Sentry Cartridge never seats, leaving the pressure control element partially open at all times to provide for clog-free operation. Quiet The cartridge’s unique rolling seal ensures that no flow passes between its moving elements, thus eliminating noise and unstable operation. Flexible The Balancing Agent can often adjust the flow rate of the fluid by simply changing the cartridge's orifice.

A Rollling Seal makes the Difference

All flow must go through the orifice plate entrance of the cartridge. Flow between the moving piston and stationary body has been eliminated, so all flow is controlled. Any velocity noise or valve chatter that could be caused by bypassing fluid is also eliminated. Thanks to the use of opposing forces, the cartridge never fully seats, leaving wide open flow channels and preventing spring distortion found in other cartridges. This means that at the design range of the cartridge, ports are wide open and the unit will pass solids up to a 1/16 inch in diameter. Engineered flow paths act as pressure snubbers to stabilize pressure control. In conjunction with the EPDM rolling seal, this snubbing effect controls the speed of piston movement, reducing wear on the cartridge parts and eliminating any possibility for the piston to rapidly bottom-out, causing a nuisance water-hammer-type noise.

A Tale of Two Valves

Two valves chosen at random, one rated flow control point. While both control flow to ±5%, one does it at 15% less flow than required. While the control is within a limit, it’s not the rated limit, and it is with a lesser differential pressure operating range than that provided with the unique features of the flow controller of the Circuit Sentry™. Those features also help provide a more stable overall flow control, not cycling between high and low limits, and when looking at rising (red) and lowering (blue) differential pressure curves, less hysteresis is exhibited (a difference in flow at the same measuring point common to mechanical control devices). As with any variable orifice valve, after the flow control element reaches its rated operating differential pressure, flow immediately increases outside the rated accuracy as should be expected, but on the Circuit SentryTM, its superior pressure-regulating flow controller continues to maintain steady control of rated flow.