Tapping into a Better Clean

Perlick needed a new cleaning system for its beer dispensing equipment...

No matter whether the draft beer is German, Belgian, Canadian or American, premium or not, you won't be able to savor the specially brewed ingredients if you don't use a premium dispensing system. Any brewer knows that handling draft beer is an exact science. The beer is sensitive to pressure and temperature and will foam when drawn unless these variables are tightly controlled. Pressure control means balanced beverage lines, factory sized to match internal keg pressure. Temperature control includes proper refrigeration along the entire line with no warm spots, no matter how far the keg is from the service area where the faucet is.

Perlick Corp., Milwaukee, WI, is the United State's premier manufacturer of simple and complex dispensing systems for draft beer. The company also manufactures modular beverage centers as well as stainless steel and brass fittings for beverage dispensing and brewing process piping systems. Many of the parts Perlick manufactures are plated with either a functional or decorative chromium finish. Because of the finishing operations, Perlick is required to meet stringent discharge limits of wastewater to the sewer and NOC discharges to the air. Emissions from its plating operations and waste treatment were not a concern for Perlick, because a highly effective wastewater treatment system had been in place for some time.

Its cleaning process was a concern because in order to be highly effective, Perlick used an open vapor degreaser with a cooling jacket that allowed some solvent to evaporate. Not only did some solvent evaporate, solvent in the tank would become contaminated quickly, which meant frequent replacement (up to 25 drums per year). Perlick investigated aqueous cleaning and chemical cleaning as potential replacements for the degreasing system. However, it found that the best and least expensive system for its parts would be a contained solvent cleaning system using trichloroethylene that minimized dragout and recycled the solvent solution.

Perlick found what it was looking for in a degreaser from Finishing Equipment Inc., St. Paul, MN. "You are not continuously replacing the trichloroethylene," noted Larry Thomas, environmental/manufacturing engineer, "because it is a self-contained system. There is a still with the system." The still refines the trichloroethylene and feeds it back to the system. "Sure, you have to top off occasionally due to evaporation and drag out, but not as often as in the past," said Mr. Thomas.

In January 1997, Perlick filled the system with 2.5 drums of solvent and since then has consumed only 3.5 drums. This compares to the 25 drums per year Perlick was using. "As far as dealing with the environmental agencies," Mr. Thomas noted, "We are well under our emission allowance. Perlick is allowed 326 lb of emissions per month, and we average just about 3 lb/month."

After several trips to monitor emissions at Perlick, the regulatory agencies were satisfied that the numbers were correct. Although much credit can be given to the machine, Mr. Thomas' maintenance and quality control monitoring ensure that the system operates properly and emissions stay within its limits.

On the first operational day of the week, Mr. Thomas checks the acid level in the solvent. If the acid level is too high, enough fresh trichloroethylene is added to bring the acid amount to the correct level. Mr. Thomas also goes through this procedure the first of every month, even if the first of the month falls on a Tuesday. Mr. Thomas also records the amount of solution added, accounting for all the solution, however it enters or leaves the system.

In the actual cleaning process, baskets that fit the degreaser are loaded with parts. The baskets are then placed on a hoist. The system is pre-programmed to move the baskets through the multi-station degreaser at a pre-determined speed. The hoist stops at the appropriate stations to allow the solvent to clean parts in the primary tank and/or the ultrasonic tank. This tank is generally used when the parts have small holes or complex geometry that make cleaning more difficult. At the end of the cycle, a buzzer sounds alerting the operator. The operator never comes in contact with the trichloroethylene.

Anything that will be plated or polished at Perlick is run through the degreaser, which equals 90% of the parts.

The degreasing system has a still for purifying and recycling the trichloroethylene. The still operates automatically, but requires cleaning at least twice a year. How does Perlick know when it is time for a cleaning? There are several indicators. If the return flow from the still is steady and constant, the still is running well. If the temperature rises above 190F, this indicates that the system is working harder and needs cleaning. Foaming also indicates that the system is working harder. If Mr. Thomas finds that he is topping off more than usual, this probably means a cleaning is in order.

The degreaser is not taken off line when the still is cleaned. The cook down part of the cleaning process usually starts the day before. During cook down residue solvents in the still are cooked off and fed into a separate drum for reuse. The heating coils are cleaned, and filters are changed. The residual waste, polish compounds, metal chips and cutting fluids are disposed of properly.

Although the solvent degreasing machine is designed to remove oils, cutting fluids and polishing compounds, solids do get into the solvent cleaning tank and need to be removed. These include polishing compounds, lint and metal shavings or burrs from the parts.

"Indirectly the unit was responsible for eliminating cyanide in the shop," noted Mr. Thomas. "Cyanide was used in the copper strike because it was forgiving and helped `clean' the parts. With the degreasing system the parts are so clean there is no transference of dirt and no need for the cyanide. Now we use acid copper."

Perlick plates parts with tin, zinc and decorative nickel chrome. It also applies paint to some parts, giving them a wrinkle-finish effect. Functional parts such as hardware, hinges, bolts and screws are plated with zinc and tin. If the cabinet has a black finish, the hardware receives a black zinc finish. "We have found that black zinc plating is less expensive than painting," noted Mr. Thomas. Hardware for stainless steel systems are plated with zinc or tin. If the part is visible, such as a faucet or spout, it is plated with a nickel chromium finish.

"We couldn't get the superior finish on our parts that we do if it weren't for our cleaning system," Mr. Thomas stated. "I think a lot of people fear trichloroethylene and degreasing systems because of all the government regulations. They don't have to, especially with this system, since everything is contained."