Pneumatic System Accelerates Grain Transfer

An inline fill/pass valve directs material to one hopper feeding either of two smaller cookers.

Conveying system cuts corn and rye grain delivery from 15 min. to 5 min. while automating distillery operations.

Dancing Goat Distillery, Cambridge, WI (dancinggoat.com), has come a long way since barreling its first batch of rye whiskey in 2017. Now a destination that offers a range of distillery experiences from tours to hands-on distilling classes, the Dancing Goat Gin Academy lets students distill and bottle their own 750-ml bottle of gin to take home. The distillery also boasts a rustic-chic tasting room where patrons can watch corn and rye become drinkable spirits, including the company’s flagship Limousin Rye and Death’s Door gin. 

While the company’s rye whiskey can spend six years barrel-aging, Dancing Goat needed only about five years to orchestrate three expansions. The most recent, which doubled the facility’s footprint to 34,000 sq. ft., moves grain nine times faster using a Flexicon Corp., Bethlehem, PA (flexicon.com) pneumatic conveying system.

The pneumatic line circuit terminates at a filter-receiver that separates carry-over material and returns it to the pneumatic feed line, eliminating waste.

Modern Techniques

With each expansion, the company wanted to preserve the traditional art and science of distillation as it adopts modern techniques. Thus, an old-school copper pot remains in service beside sleek distillation columns. At the cookers, where grains and malt are turned into a mash for fermentation, the company has twice upgraded its loading methods. Originally, workers hoisted dozens of 50-lb. bags of grain to load three 240-gal. cookers. When those were replaced by two 1,900-gal. cookers, Dancing Goat began receiving grain in bulk bags, unloading them into the vessels using a Flexicon bulk-bag discharger and flexible screw conveyor. 

After its latest expansion added a third, 3,000-gal. cooker, the distillery installed an 85-ft.-long PNEUMATI-CON pneumatic conveying system. The system transports the grains to two 7.5-cu. ft. hoppers, one feeding the two existing cookers and one feeding the new cooker.

“The pneumatic system can load three times as much grain in one-third the time,” reported Mike Reiber, former Director of Operations. “Instead of driving fork trucks to the bulk-bag discharger at the cookers and charging the cookers there, we created a grain-handling room and based our pneumatic conveying system there. It improves the process and is less painful for the operators.”

Located on the opposite side of the facility from the cookers, the grain room houses the intake and terminus of the pneumatic circuit, and a bulk-bag discharger mounted on load cells. With a forklift, workers load the bags into the discharger using a lifting frame that nests into receiving cups atop the discharger’s frame posts. 

Once the bag spout is secured to a SPOUT-LOCK clamp ring, the grains—milled to a flour-like consistency—flow into a 5.5 -cu. ft. floor hopper, from which a 5-ft.-long flexible screw conveyor, inclined at 45 deg., feeds the grain into the pneumatic conveying line using a pickup adapter that includes an air inlet filter. Load cells supporting the discharger transmit loss-of-weight signals to a PLC that stops the screw conveyor once a pre-set batch weight has been fed into the pneumatic line.

The 5-in.-dia. pneumatic line—under negative pressure generated by a 30-hp vacuum pump—transports the entire batch with no residual, across the facility to the two hoppers installed over the cookers. Inline fill/pass valves, located above each hopper, guide the grain to one hopper or the other, depending on the recipe. 

The grain discharges into each cooker through a rotary valve. Above the twin cookers, a diverter valve controls whether the grain discharges from the hopper to the first or second cooker. The second hopper discharges to the third, larger cooker.

On the return side, the line runs from the hoppers back to the grain room to a 48-in.-dia. filter-receiver with cartridge filters that separate the conveying air from carry-over grain dust. Reverse-pulse air nozzles dislodge accumulated material. The material enters a floor hopper with a rotary valve that returns it to the conveying line feeding the cookers.

“That means I don’t have to worry about grain being aged at the bottom of my conveying line or about grain backing up in the filter-receiver,” Reiber said. “It also minimizes any concerns about attracting bugs or other pests and it gets the maximum amount of grain into the cookers.”

A loss-of-weight bulk bag discharging system, with integral flexible screw conveyor, feeds grain by batch weight into a Flexicon pneumatic conveying line that, in turn, feeds cookers on the opposite side of the facility.

Pneumatic conveying

The pneumatic conveying system, which can move as much as 14,000 lb./hr., reduces the time operators spend loading and discharging the bulk bags. Instead of taking the bags to the use point, they’re now taken to the grain-handling room close to where they’re stored. The forklifts travel about 50 ft.,  so the amount of handling has been cut by 80%.

Corn and rye, the grains Dancing Goat uses the most, flow from the bulk bags faster. “We were delivering a bag in roughly 15 minutes before. Now it’s in the 5-minute range for a bag of corn and 7 minutes for rye, with both bags weighing 1,750 lb., Reiber said. A typical batch requires discharging six to eight bulk bags. “The operators who were here before we upgraded are amazed at how much less work and how fast the pneumatic system transfers the grain. We’re doing more with less work and in less time.” The operators are freed to perform other tasks in the distillery.

The operation is also cleaner and safer because the batching system is contained and operates under vacuum, preventing the grains from spreading dust. “We already make a flammable product, ethanol, and we don’t want to add potential fuel—airborne dust—to a zoned and classified space,” Reiber reported.

In the grain room, the bulk-bag discharger contains dust and ensures reliable flow using several subsystems. At the bag spout interface, a SPOUT-LOCK clamp ring makes a dust-free connection to the floor hopper. As the bag empties, a TELE-TUBE telescoping tube lowers the clamp ring, applying continual downward tension to keep the spout taut, promoting flow. Meanwhile, FLOW-FLEXER bag- activator plates raise and lower the opposite bottom edges of the bag into a V shape, directing all of the grain out the spout.

“We use the bag activator plates every day on every grain. It helps break up the cube that can form during transport,” Reiber commented. The company also relies on the discharger’s POWER-CINCHER flow control valve that uses pneumatically driven bars to close concentrically on the spout. “It’s a great tool when we need to restrict the flow or tie off a bag before it’s empty. It’s ideal for handling malt, which starts out blocky but then flows like water once it gets moving.”

In addition, the discharger’s posts can be raised or lowered to accommodate off-size bulk bags. “Our malt supplier’s bulk bags are about 14 inches longer than the normal ones,” Reiber noted. “But it only takes maybe five minutes to adjust all four posts.”

Non-stop advancement

While the distillery has become a destination for whiskey and spirits lovers, Reiber reported the company is only partway into its journey, with plans to load the grains from bulk silos instead of bulk bags. 

“We plan to tie in the silos to piggyback on the pneumatic conveying system,” he said. “The goal is to cook, ferment, and distill around the clock, and this system has brought us much closer to doing that.” EP