By Ed Barr, P&L Specialties
The grapes have been harvested and are ready to be processed. The winemakers stand ready to perform their magic on the fruit. To the untrained eye what happens next doesn't appear to amount to much. That, however, is not the case. Sorting those grapes to remove MOG (materials other than grapes)—those raisins, leaves, shot berries, spoiled fruit, bits of stem jacks, bugs (Figure 1)—is a crucial step. The sorting must be done before loading the grapes onto the conveyors that transport them to the fermenting step.
A process that can be done exclusively by hand or by means of a special machine, sorting adds time, but it's time well-spent to assure the consumer a higher quality of wine.
In many wineries, machine sorting has replaced hand sorting, which introduces another set of concerns. "If the sorting table shakes too rapidly or not fast enough, if its movement is uneven or if it starts and stops, the grapes can be damaged," explains Wes Snodgrass, P&L Specialties general manager. "They will not be sorted well, and either the process will be delayed while sorting is completed or MOG will find its way into the wine. None of those alternatives is good news to a winemaker who, in addition, might have to pay extra hours to a staff that's waiting around with nothing to do while a batch is re-sorted or for machinery to be fixed."
P&L is a California-based designer and manufacturer, integrator and supporter of customized winemaking, food processing and water-treatment machinery. Its grape processing equipment is widely used by wineries in the U.S. and Canada. In business since 1984, P&L has established a reputation for quality, value and unparalleled service. Its products include sorting tables, bin dumpers, destemmers, Le Trieur sorting tables, air knifes, receiving hoppers, catwalks, belt and screw conveyors, rotary screens and mixers. P&L also represents several high-quality, complementary, European pieces of equipment that can integrate with P&L's own systems. Its patented Le Trieur sorting machines (Figure 2) was recognized by Wine Business as one of the "Top 11 Products for the Small Winery."
All in the Movement
Le Trieur sorts the grapes based on the principle of oscillation, with a gentle shaking motion that removes the MOG. It uses a wedge-wire screen, which is flat on top with the point facing down, and is available with a capacity of up to 10 tons per hour. The motor drives a counter-weighted flywheel assembly via a flexible, cogged drive belt. The counter-weighted flywheel assembly also drives the eccentric rotating assembly that propels the bed of the machine, thus creating the forward and aft liner motion for processing. The counter-weighted flywheel assembly acts to negate the forces of the bed thrusting forward and aft, allowing smooth operation of the machine. In essence, there is a balance of forces.
It is especially important to be able to smoothly control the motor while the speed of the machine is either increased or decreased, as the balancing force is less stable during changes in rpm.
When P&L set about replacing the variable frequency drives (VFDs) on its sorting tables and on Le Trieur, its short-term goal was to find an efficient solution to the challenge presented by one of its off- the-shelf units. "As the sales of these units increased, we began to face delivery lead time and serviceability issues with the original article controllers," explains Greg Nau, sales engineer. "We offer a comprehensive two-year warranty on our equipment and most electronic control manufacturers only provide 90 days to one year of warranty. We were essentially in the position of extending the manufacturers' warranty, so we demand solid performance and robust durability."
For P&L, keeping the big picture in mind is key. "We see our reputation for keeping our commitment to quality and performance as our No. 1 tenet to ongoing business," says Carl DeBenedetti, purchasing manager. "Our equipment is not the least expensive on the market, and our customers expect it to really deliver on long-term value and performance."
P&L has been using the Lenze-AC Tech stainless steel MC NEMA 4X drives on its sorting tables, several conveyors and Le Trieur, with good results. What exactly determines good results? "Lower failure rates, an excellent level of internal parameter programmability and smooth operation of the motors, especially during acceleration and deceleration," explains Snodgrass. "Plus, we really like the drive's look and performance. We use many of the programmable parameters to control variables such as speed, ramp up/ramp down time, minimum and maximum Hz settings, over-voltage and over-amperage protection."