In comparison to traditional ‘line of site’ control valves (such as ball valves, butterfly valves and pinch valves), which direct high velocity slurry towards the valve’s body and pipe wall, our patented trim design acts as a variable orifice, centering the abrasive flow. This protects the pressure containing valve body and the integrity of the downstream piping from erosion.
There are no 'off-the-shelf' SlurryFlo control valves; each one is manufactured with a unique seat plate geometry. Based on application requirements, the port area is waterjet cut and CNC machined to our engineers’ exact specifications.
Our design philosophy is to achieve an 'equilinear' valve characteristic for maximum wear resistance; however any custom flow characteristic can be achieved. There are literally infinite trim geometry possibilities. And, if flow conditions change over time, we can retrofit the existing valve with a new seat plate (i.e. an alternate Cv or flow characteristic can be obtained without changing any other parts).
The custom seat plate works in concert with the valve's gate resulting in a centered orifice with variable control.
If increased flow is temporarily required, the gate can be retracted beyond its normal throttling positions. The concave gate profile always matches valve's bore.
These valves are designed for modulating, however the gate may be closed if required. The metal-to-metal seating surface provides a Class IV shutoff, blocking 99.99% of the valve's rated Cv.
The gate and seat plate are available in dozens of standard and exotic metallurgies. These trim components are then coated with a state-of-the-art hard overlay, such as tungsten carbide (applied via PTAW process). This provides a corrosion proof trim that resists abrasion incredibly well in severe service applications.
Our small diameter control valves incorporate a unique wear technology to provide long-lasting erosive flow control. In place of hard coated metal parts, the gate and seat plate are made entirely of sintered tungsten carbide. The end result is a valve with trim components that approach the hardness and wear resistance of diamond.
Due to our patented design, only the trim components are exposed to erosive flow. Once they do eventually wear out, the parts can be field replaced to reset the service life clock.
Each trim replacement essentially provides a new valve at a fraction of the cost.
Similarly, if flow conditions ever change, a new seat plate can be specified to provide an increase or decrease in flow. There is no need to replace the entire valve assembly (often the case with other valve designs).
The bonneted gate design allows for a compact stem seal assembly (i.e. around the gate stem). This set-up reduces operating thrust requirements, provides more precise gate modulation and minimizes potential leakage. SAF engineers select the proper packing and scraper materials based on fluid composition. The entire stack is then energized by a packing follower that is live loaded with Belleville springs.
Canadian patent number: CA 2 489 079
United States patent number: US 7,431,264 B2
