JDB - Continuous Dense Phase Conveying Systems
Continuous Dense Phase Conveying Systems are often built to convey material long distances (over 1000’) and/or at high tonnage rates (more than 25 tons/hr.). They are the most efficient, and feature the lowest average material velocity compared to any other form of pneumatic conveying. Continuous Dense Phase Systems typically operate with two pressure vessels working in tandem or with a single pressure vessel equipped with a discharge valve; all the configurations continually convey multiple batches of material through a single pipeline at once. The low material velocities and minimal wasted energy in a continuous system is due to the fact that a continuous system has little to no blowdown in between batches being conveyed.
Blowdown occurs most commonly in a Batch Dense Phase System when the single slug of material being conveyed reaches its destination and begins exiting the convey pipeline. As the single slug of material exits the pipeline and the resistance the slug caused is eliminated, the compressed air that was behind the slug of material, will race down the pipeline at its terminal air velocity (approx. 1000 – 2000 ft. / Min.), this known as blowdown. During this blowdown period any material left in the pipeline will be moving close to the same rate as the terminal air velocity.
A Continuous Dense Phase system has little to no blowdown, because as soon a slug of material in a continuous system reaches its destination, there is another slug right behind it. By minimizing the blowdown, Continuous Dense Phase Pneumatic Conveying Systems have the lowest average material velocity, air consumption, and exhaust CFM requirements. This translates into a system that requires less power consumption, lower dust collection requirements, and less wear and tear on pipeline components.
Continuous Dense Phase Pneumatic Conveying System Configurations
At JDB Dense Flow we’ve built Continuous Dense Phase Systems conveying distances in excess of 1000’, delivering dry, free flowing material at rates higher than 25 tons/hr. Our Continuous Dense Phase Pneumatic Conveying systems feature an advanced air delivery system, and electric controls that monitor system performance which allows our systems to operate without air boosters along the convey pipeline.
Air boosters are devices that inject air into a dense phase system, and are mounted along the convey pipeline (sometimes as often as every 5-10 feet). Air boosters can cause increased wear on the pipeline opposite from where they are mounted, as well as increase the velocity of the material being conveyed, shortening pipeline components lifespans. Boosters can also dramatically increase system installation costs.
The Advance Air Delivery Systems uses accurate pressure monitoring devices and adds air to the system only when necessary to maintain an optimal conveying pressure. By adding air only when necessary no energy is wasted, and the average material velocity is kept low by maintaining the systems optimal conveying pressure. The system performance is monitored through a touch screen display, and operators can make changes to system settings if necessary.
Along with the Advanced Air Delivery System our Continuous Dense Phase Conveying Systems feature Dense Flow components designed enhance the systems performance and minimize system downtime. The Dense Flow Cone Valve is designed to minimize moving parts throughout the system, and is used to charge (fill), vent, and seal pressure vessels used on JDB Continuous Dense Phase Systems. Most competitors require three valves to accomplish the same results as a single cone valve. The Dense Flow Pocket elbow was designed for use on the convey pipeline where a turn is necessary. The unique design of the pocket elbow and rugged materials of construction means it can outlast other elbows 10-1.
The Dense Flow Cone Valve is cast from ductile iron and has a machined sealing area. Its rugged construction and unique design minimize moving parts, decrease system downtime, and reduce overall system maintenance costs.
The Dense Flow Pocket Elbow is built from cast ductile iron, and its unique design helps to increase the elbows lifespan by protecting its most vital area. The elbow traps material in a “pocket” at the material deflection point dramatically reducing wear on the elbow.