Clean Plate Club
Got a lot of dishes you need washed in a hurry? Flight-type warewashers have always been the go-to warewashing equipment for high-volume feeders: resort hotels, casinos, cruise ships, hospitals, schools and colleges, prisons—you get the idea.
These direct-load conveyor machines are the behemoths of the warewashing world. And like big creatures in the animal world, they used to have outsized appetites for water and energy. Flight-type machines can wash tens of thousands of dishes a day, but they also can use thousands of gallons of water and a ton of kWh or Btu to heat that water, day in and day out.
That changed several years ago as manufacturers began outfitting their rigs with features that made them more water and energy efficient. More changes came in February 2013 with the implementation of the Energy Star Version 2.0 specification for commercial dishwashers. The new specs included flight-type machines for the first time, and manufacturers responded by introducing models that sip rather than gulp water and incorporate even more features designed to cut energy use, saving you thousands of dollars a year in water and energy costs.
The difference between a flight-type dishmachine and a rack conveyor, obviously, is the use of racks themselves. In a rack conveyor, which moves racks of wares on a flat conveyor belt, you must use racks for all wares, from glasses to pots and pans. In a rackless machine, most wares go directly on the conveyor belt, which is equipped with vertical pegs to hold them upright. However, even in a rackless flight-type machine you still need racks or containers for items such as glasses and stemware, flatware, utensils and some other items.
Your decision to go with a flight-type unit likely will be based on volume. Large rack conveyors can wash about 300 racks per hour. At an average of 25 pieces per rack, that’s about 7,500 dishes per hour. Flight-type machines typically wash around 10,000 dishes per hour or more.
But volume is just one factor to consider. If, for example, all of those dishes don’t come to a centralized warewashing location, a flight-type machine may not be for you. Conversely, a hospital using a lot of different-sized wares, including insulated tableware, for example, may decide to use a flight-type machine even if it doesn’t generate that many dirty dishes. The reason: You can specify the spacing of the pegs on the flight-type conveyor belt to fit your particular wares, wares that may not fit well in racks.
Space is another consideration. These bad boys are big, with the smallest running about 14 ft. in length—including load and unload ends—and a multi-tank machine with prewash and blower dryers stretching to as much as 40 ft. or more. Some custom jobs have gone up to 54 ft. and literally around the bend, making right-angle turns in the dishroom. And that’s just the machine itself. You’ll want at least 3 ft. of feed surface or open space at the front end for loading and plenty of room for wares to dry and dish carts to maneuver at the unloading end.
Note, too, that you can locate some models next to a wall with just 3-4 in. of clearance while others require a couple of feet on both sides.
You’ll also need either ceiling or aisle clearance for doors depending on how they open. A few manufacturers use vertical doors that slide up and require as much as 8½ ft. of clearance to the ceiling, although one offers short doors needing 7½ ft. of clearance as an option. Other makers feature cabinet-style swing-out doors that open into the aisle, requiring 28 in. of clearance or less.
Most makers design and build their flight-type machines in 3- or 4-ft. sections so they fit through existing doorways. And because they’re assembled on site, almost every flight-type conveyor is a “custom” warewasher, so you can spec what works best for your operation.
Your Basic Behemoth
Any warewasher has wash, power-rinse and final-sanitizing-rinse cycles. Flight-type machines are no different. Basic models have a wash tank, a power-rinse tank and a final-rinse “chamber.” But while manufacturers will refer to the final-rinse chamber as a tank, NSF Int’l. does not. For certification purposes, NSF Int’l. counts as “tanks” only those chambers that deliver and hold heat and water. Because the booster heaters required to warm water to 180˚F for the final rinse are either optional or sold separately, NSF Int’l. doesn’t count the final-rinse chamber as a tank. So, even though manufacturers would regard the preceding example as a three-tank unit, NSF Int’l. would call it a two-tank machine.
Most manufacturers recommend a pre-wash section to remove food scraps before dishes or pans go into the wash chamber. Usually, the pre-wash section doesn’t have a heater either, but it does have a recirculating pump. Designs rely on both the temperature of the water coming into the machine and fill from the wash-tank and power-rinse-tank overflow to keep the pre-wash water between 130˚F-140˚F.
Manufacturers typically count the pre-wash as a tank—even though NSF Int’l. doesn’t unless it’s heated—so a flight-type machine with a pre-wash, wash, power rinse and final rinse usually is described as a four-tank machine by manufacturers. Add another wash tank, and you have a five-tank machine. If your operation serves a lot of proteins or fried foods, the more tanks the better.
You can hook up flight-type warewashers to an existing steam generator, a gas line or electric service. Most machines are electric, and depending on the manufacturer, you can choose 208V, 220V, 230V, 240V, 360V, 460V or 480V models to match your available service.
Tank capacity typically ranges from 36-40 gal., although pre-wash tanks on some models are smaller than the wash and power-rinse tanks. (As previously mentioned, not all pre-wash tanks are heated; hot-water overflow from the wash and power-rinse tanks often replenishes unheated tanks.)
The combined energy draw of tank heaters on standard models ranges from about 45kW-60kW, but newer Energy Star models draw anywhere from about 15kW-30kW. Similarly, booster heaters increasing water temperature to 180˚F for the final sanitizing rinse can run from about 30kW (to achieve a 40˚F rise) to 60kW (for a 70˚F rise) on a standard model, but Energy Star machines only need about half that number of kW. We will discuss how makers achieve the energy savings later.
Tightening Your Belt
Most models offer a choice of belt speed so you can slow the machine down to wash particularly dirty loads, such as cookware. Some machines only have two or three speeds. Others offer variable-speed belts, but the range of speeds on most models usually will be between about 4-9 ft. per minute. Remember that the NSF Int’l. requirement for sanitizing governs the maximum speed. Any faster and the dishes won’t get hot enough in the final rinse.
You can order belts in a variety of configurations. Belt material can be a pliable polypropylene that’s easy on china; hard, unbreakable stainless, which is usually spec’d for prisons, for example; or a substance that falls somewhere in between. Some makers offer all three options; others don’t.
Standard peg height and distance between pegs also can vary from one manufacturer to another, but most manufacturers will work with you to provide a belt that will work with all or most of your wares. Peg spacing of 2-2½-in. is common for dishware, while you may want 3-in. spacing for pots and pans. You can even spec sections of a flat conveyor belt to accommodate racks of items such as utensils, glassware and flatware.
Make sure you specify a belt and pegs that properly support the wares you use. If you don’t figure out peg configuration in advance, your dishroom employees can end up forcing wares to fit, which leads to jamming, breakage and other problems.
All flight-type machines come with a limit switch on the unloading end that stops the belt if no one’s there to catch dishes. Most models have at least two start-stop buttons, one on the main controls and one on the loading end. Some have three, including another switch at the unloading end. Most also offer a conveyor-reversing switch and an auto-kill switch that shuts the conveyor off in case the belt jams to prevent the motor from overheating.
Other features, including automatic tank fill, low-water warning and temperature-limit switches as well as door-safety switches, are common to virtually all models.
Where The Savings Are
Energy Star Version 2.0 specs for flight-type machines focus on two areas: the amount of water used (in gal./hr.) for the final sanitizing rinse and energy used when the machine is idle. Warewasher manufacturers already had made inroads in both areas before the specs went into effect more than two years ago. But improvements in the past year have been dramatic.
NSF Int’l. requires that warewashers produce at least 180˚F water at the spray manifold, fulfilling the U.S. Food and Drug Administration’s Food Code requirement to heat wares to 165˚F for 15 seconds, rendering them sanitized. The cost of water—and the energy needed to heat it—continues to rise. Reducing the amount of final-rinse water used kills two birds with one stone. Manufacturers have found ways to distribute final-rinse water more evenly and effectively, raising the wares’ surface temperature to the required 165˚F for 15 seconds.
First, makers have improved final-rinse spray-arm design so they use less water to cover a larger area. One, for example, uses an arch-shaped final-rinse arm with a cross-coverage spray pattern. Machines now do a better job of balancing water flow and pressure from final-rinse pumps. A new addition on another model uses an electronic eye scan to detect the presence of wares, activating the final rinse only over dishes it detects on the conveyor below, saving hundreds of gallons.
Finally, power-rinse tanks in most Energy Star-qualified flight-type warewashers do such a good job of removing all traces of chemicals used to get the dishware clean that less water is needed in the final sanitizing rinse. The result is that while standard machines use anywhere from around 300-425 gal./hr., Energy Star-qualified warewashers use as little as 57 gal./hr.
Overall energy efficiency comes from improvements in a number of areas. Look for machines with insulated, double-walled construction. They retain heat better, keep the dishroom cooler and are less noisy. Some manufacturers offer insulated tanks as an option. Ask what the payback is, but they’re a good idea in most instances.
All makers have designed energy-efficient machines to cascade final-rinse water back into the power-rinse tank, power-rinse-tank water into the wash tank and wash water into the pre-wash tank, saving costs to heat incoming water. They’re finding additional savings in removing debris from wash water so it cleans effectively longer and uses less detergent.
Manufacturers have designed better scrap baskets and screens and positioned them more effectively. A couple of manufacturers also have added active filtering. One uses a cyclonic separator in the power-rinse tank to remove fine soil, improving the rinse effectiveness as well as the wash when the cleaner rinse water cascades back into the wash tank. Another offers a 2-ft. section that removes food soil from wares before it even reaches the pre-wash tank, again improving cleaning effectiveness and detergent life.
Not Just Hot Air
An energy-saving option that usually has about a two-year ROI is a heat-recovery unit. It’s comprised of a heat exchanger that captures the heat in the exhaust air and uses it to warm incoming water before it enters the booster heater. Makers say these units can raise incoming cold water (from outside) to as much as 110˚F-120˚F; the booster then heats the water to the 180˚F required for the final rinse. Bottom line, heat recovery lowers the cost of pre-heating water in your operation’s hot-water heaters.
Most municipalities require Type II condensate venting over flight-type warewashers and you’ll need an exhaust fan capable of moving anywhere from 550 1,200 cfm to remove heat and steam from the dishroom. One manufacturer makes a model with a heat exchanger that’s so effective it condenses steam generated inside the machine so that it does not need a hood (in some municipalities; you must check local codes). It could enable you to install the machine without the expense of installing a hood over it. Also, many machines have a single vent point, making it easy to tie the machine into an exhaust duct, but some models have multiple vent points. Take these issues into account when planning dishroom layout.
Also, remember that dishes and glassware heated by 180˚F final-rinse water will tend to flash dry when they come out of the machine. But other ware—melamine and plastic ware used in healthcare, for example, or many pots and pans—won’t. You may want to invest in a blower dryer as it also helps reduce spotting, even on glassware. Many manufacturers offer the option of two blower dryers.
Nothing affects dishmachine performance more than food soil, which is why manufacturers make scrap baskets and strainers/screens easy to remove and clean.
To perform at their peak, however, all parts of flight-type warewashers need to be kept clean. Virtually all makers design easy-to-remove parts that need cleaning, such as spray arms, curtains, etc. One manufacturer color-codes removable parts in the machine so employees remember which ones to clean. Machines should be dismantled and cleaned at least daily, if not after every shift.
One manufacturer offers an auto-clean cycle, which flushes the wash arms and uses special nozzles in the chambers to flush the machine interior. The cycle helps maintain performance, especially when used at the end of a meal period.
Another simple item you might want to add to your spec list is interior lighting. If employees can’t see it, they can’t clean it.
A feature you’ll want, especially if your operation is in an area with hard water—e.g., Las Vegas or Austin, Texas—is an auto-deliming cycle. Heat and water inevitably create mineral deposits in equipment like warewashers, and if you don’t remove them on a regular basis, spray nozzles will clog, heating elements will underperform and your dishes won’t get clean.
Makers offer a host of features and options not covered here, so do your homework. And remember, a flight-type conveyor is typically the single most expensive piece of equipment in the kitchen—costing from about $45,000 well into six figures for custom rigs—yet it’s operated by the lowest paid employees. Choose a model that’s easy for employees to operate and maintain.
In the this issue’s Gallery, we include specifics on flight-type warewashers from a range of manufacturers, including several brand-new models.
BLAKESLEE DISHWASHING SYSTEM
Blakeslee’s Flight-Type Dishwashing Systems are modular and can be designed to fit the structural constraints of any dishroom. Three-tank units come in 120-, 140- and 150-in. models with a 20- or 30-in.-wide belt. The smaller belt allows the warewasher to wash up to 9,066 dishes/hr., while the larger belt allows the unit to clean up to 13,900 dishes/hr. The exclusive “underslung conveyor link design" lowers the belt height, allowing comfortable, direct loading of dishes/plates, trays and racks at waste level—no lifting. Conveyor rods are ½-in.-thick stainless. Machine designed to send overfill water from the wash tank into the pre-wash tank, and makeup water is reclaimed from the rinse tank. Wash water and its energy is recycled and used in all of the tanks.
CHAMPION INDUSTRIES SLIMLINE
Champion’s Dual Rinse E-Series SlimLine 24-in.-wide conveyor flight-type warewasher offers a 25% reduction in depth compared with traditional flight-type warewashers, providing the same options in a smaller footprint. The Energy Star-qualified unit can fit through a standard doorway, which can help reduce installation costs. The warewasher can wash 13,000 dishes/hr., while new technology reduces water consumption to only 57 gal./hr. Despite the slim footprint, the SlimLine warewashers can wash everything traditional flight-type warewashers are capable of washing. The warewasher is available with the company’s NRA Kitchen Innovations Award-winning heat-recovery technology that captures steam and uses its energy to preheat incoming water.
HOBART FT1000 ADVANSYS
Hobart's FT1000 Advansys flight-type warewasher is a 2015 NRA Kitchen Innovations Award winner. It features Auto Clean, which cleans the inside of the unit automatically using capless wash arms and rear nozzles in the chambers. The Auto Delime feature is customized for each site and delimes the booster heater as well. Automatic Soil Removal uses a dedicated tank and specialized soil-removal wash arms to isolate soils and pump them to an external scrap basket, extending the useful life of the wash water and reducing detergent consumption. Ventless technology enables the machine to operate without a direct vent connection and captures heat from the waste air to heat the wash tank, blower dryer and final-rinse tank. This reduces the facility’s water-heater workload, saving over 44 kW. The warewasher handles 10,611-14,316 dishes/hr. at a rinse rate of 58 gal./hr. Energy Star rated, this unit is estimated to save $26,000 a year in operating costs, providing the lowest total cost of ownership for a flight-type warewasher, according to the company.
INSINGER MASTER RC
Insinger’s Master RC 3-tank, rackless flight-type warewasher can wash up to 14,300 dishes/hr. with a final-rinse consumption of 124 gal./hr. The company’s patent-pending CrossFire Wash System power sprays water horizontally as well as from above and below, cleaning and sanitizing dirty wares. An electric photo eye automatically operates the final-rinse solenoid only when wares pass, saving water and energy. The photo eye also activates an adjustable timer control; if no wares pass during the set time, the machine shuts down. The conveyor is driven by an independent ½-hp motor and features a trip bar at the end of the unload section that stops the conveyor if any wares reach the bar.
Jackson’s LoH2O flight-type warewasher features single-point exhaust that ensures proper ventilation control. Specially designed wash arms offer nonclogging, convex jets; equalized water pressure; and uniform cleaning coverage. The unit recaptures final-rinse water and pumps it through the power rinse to optimize rinse quality. The unit’s rackless 2-speed conveyor moves up to 11,094 dishes/hr. at a rinse rate of 58 gal./hr. Its 29-in. belt width and 25-in. overhead clearance accommodate larger wares. Double-wall insulation keeps the water inside hot and outside surfaces cool.
MEIKO M-IQ B-L74 SERIES WITH GREENEYE
MEIKO’s M-iQ B-L74 Series of flight-type warewashers features a multistage filtration process that collects food soil in each tank then flushes it out completely in high-pressure cycles, improving performance and reducing detergent consumption by up to 50%. The Energy Star-qualified, 3-tank warewashers can wash up to 14,993 dishes/hr. using less than 60 gal./hr. of water; the conveyor belt is 29½-in. wide. A brand new option is the GreenEye integrated, water-saving system that detects dishes on the belt and only triggers sprayers as the dishes pass. The system includes GreenCoach interactive lights to direct employees on where to load dishes in optimal “lanes” on the belt as well as the GreenFilter, a dedicated hydrocyclone separator in the power-rinse tank that continuously and actively removes even the finest soil particles, extending the life of the wash water.
Stero’s STPCW-ER 3-tank rackless flight-type warewasher features a maximum conveyor speed of 9 1/5 ft./min. and a maximum final-rinse consumption of 98 gal./hr. Its 2-stage final-rinse system provides efficient water distribution and heat transfer, washing up to 13,000 dishes/hr. with a water and energy-consumption savings of up to 70%. The warewasher features a 180˚F rinse-water control as well as a safety stop at the unload end that eliminates ware breakage and pileup. All of the tanks fill to their proper levels at the push of a button. If, for any reason, water levels should drop during operation, a water-level control automatically restores and maintains the correct levels.