THE VORTEX ORIFICE SLIDE GATE ADVANTAGE
One fundamental difference when comparing the Vortex Quantum Series Orifice Slide Gate to other valves such as a butterfly valve or a bull nose knife gate is the Vortex Orifice Gate is designed specifically to handle dry material while the other valves are not. Butterfly valves and bull nose knife gates are designed for gas and liquid applications. They are effective valves in those environments, but suffer numerous problems when misused in a dry bulk handling application.
The butterfly valve’s design creates a handling problem for dry bulk solids, as the disc is located in the immediate flow stream of material creating significant flow restriction. Many engineers design the entire conveying system with larger than necessary piping to accommodate this bottleneck in the valve.
The soft seals in a butterfly valve can create another problem. The soft seals allow the disc or blade to produce a bubble-tight seal in the closed position. The very nature of dry solids does not allow these types of valves to create a tight seal because dry material cannot be displaced like a gas or liquid. Many issues can arise over time as the seals begin to erode and tear. 
The exposed soft seat of the butterfly valve is also susceptible to the material flow stream. This causes additional wear points and eventual leakage of material and/or conveying pressure through the valve even in the closed position. In a powder handling application, particles tend to migrate through the stem of the butterfly valve causing the valve to seize.
Bull nose knife gates would seem more logical for dry solids handling than butterfly valves. However, the soft seals typically used for gases and liquids are also exposed to the material flow stream of dry material. Upon closing, the leading edge of the blade tends to compact dry material into the soft seals causing seal abrasion preventing the valve from closing. The packing gland (the sealing area designed to prevent air and material from escaping into the bonnet) of the valve is also exposed to abrasion as material migrates through the packing seals on opening and closing strokes. Once the packing gland seals are worn, air and material are allowed to escape into the atmosphere.
With both designs, replacement or rebuilding of the valves can be cumbersome as they are generally heavy metal cast valves. This adds a significant amount of unnecessary weight to the valve making it difficult to install, and does not allow maintenance while the valve remains in the conveying line. Not being able to perform quick maintenance requires plant downtime to fix the valve and in some cases, it is cheaper to replace the entire valve rather than replacing new seals and parts.
These problems are eliminated with Vortex’s Quantum Series Orifice Gate design. It utilizes a stainless steel rectangular plate with an orifice (circle) machined through it. The machined plate then actuates between two compression-loaded hard polymer plates. In the closed position, the compression load on the blade prevents material and conveying air from escaping through the valve or into atmosphere. In the open position, the orifice in the blade aligns with the conveying line eliminating flow obstructions or exposed seals that might be vulnerable to wear from the material flow stream. The valve also “self-cleans” material from the seat on each stroke of the blade so there is no bridging or packing of material.
The Quantum Series Orifice Gate’s preloaded hard polymer seals compensate for wear unlike the butterfly valve and the knife gate. This extends the life of the valves and requires less maintenance. The load on the seals is also adjustable without removing the valve from service reducing downtime costs. If the valve ever does need to be removed from the conveying line, its construction is lightweight compared to cast valves.
For more information on Vortex’s slide gates, please visit our website at www.vortexvalves.com.
Additional Information:
For more than 35 years, Vortex has provided quality slide gates, diverters, and iris valves designed specifically for handling dry bulk solids in gravity, vacuum, dilute, or dense phase applications. Vortex valves are engineered for dependability, durability, easy maintenance, and offer proven solutions to material handling and process efficiency problems. With an in-house team of engineers, Vortex valves can be completely customized for individual applications or special installations.
