What is Dry Steam Cleaning and What is it Used For?

Dry Steam Cleaning is a sanitising method favoured by many food, beverage, and pharmaceutical producers as a high temperature, relatively dry, chemical-free process for cleaning production equipment in accordance with various codes and standards. The steam is hot enough to sanitise but because it is superheated, the steam has a low water content, effectively leaving behind dry surfaces. The process was developed in Europe where concerns about high water use, chemical sensitivities, waste management, and stepped-up hygienic standards led away from more traditional sanitising procedures. This article briefly describes the process and equipment, some popular applications, and some other cleaning alternatives.

Fundamentals

A typical dry steam cleaning setup includes a tank for storing water, a boiler, a delivery hose, and various nozzles and valves. Most of the larger industrial machines rely on three-phase power to the boiler although smaller capacity units are produced which operate on single- phase power. These boilers should comply with ASME codes or Euro standards. Larger units may incorporate multiple boilers for greater steam volume. Systems are generally designed for portability, requiring only mains voltage supply. Systems are often mounted on casters.
and larger, 415v industrial machines sometimes offer dual hoses to permit two workers to work from the same machine.

Machines may have a single, refillable boiler or a two-tank system where feed water is kept in a separate non-pressurized tank and fed to the boiler as needed. Single tank systems must be depressurised before refilling while two-tank systems can be refilled on the fly, thereby eliminating the downtime associated with the cooldown, refill, and reheating of the unit. Some machines offer a continuous fill system, which is fed from an external water supply. Others permit the delivery of sanitising chemicals along with the steam.

Typically, a brush is used in conjunction with the nozzle with special configurations available for cleaning floors, around pipes, and so forth. Special systems are available for permanent attachment to conveyors. Often, the dry steam process is followed by a wipe with a microfiber cloth to pick up any remaining residue.

Advantages

Steam is delivered to the nozzle over a range of pressures and temperatures; steam at 127°C will kill any microbe on earth with direct contact. Many pathogens lie beneath a biofilm, however, which protects them from the killing power of steam. The steam, instead, strips away the biofilm and along with it any microbes it may be harbouring. For a similar reason, chemical sanitising agents must be allowed to dwell on surfaces to give them
sufficient time to break through the biofilm. Steam also avoids the possibility of bacteria developing resistance to chemicals. The steam, under pressure, can work its way into cracks and crevices but does not blast grime everywhere the way hosing or pressure washing can. Water use is minimized as is the volume of cleaning residue.

Applications

The sanitising requirements of the food, beverage, and pharmaceutical industries make facility sterilisation by dry steam a good fit. Dry steam is used safely around control panels, conveyors, directly on walls, within ducts, etc. – all places where grease and residue can accumulate and harbour bacteria. Any facility that packages fresh fish, poultry, meats, cut produce, and similar items must be especially vigilant in its sanitation regime. The use of dry steam allows surfaces that contact food to be sanitised without chemical residue. Production machinery and equipment can be sanitised during worker breaks without shutting down production. Beverage makers use dry steam to clean bottling machines, conveyors, wooden barrels, etc. Refrigerated storage facilities may be cleaned without removing food products. Motors, wiring, and other electrical equipment may be degreased and sanitised without fear of harming the equipment.

Beyond those industries, others are finding applications for dry steam cleaning. Hotels, spas, and gyms are starting to use the process to kill bedbugs and other insects in carpets and bedding and to sanitise surfaces that come in frequent contact with their guests. Airlines and passenger trains and buses are increasingly using dry steam for the sanitation of their passenger compartments. Auto detailers are using the technology to clean and sanitise automotive interiors. Medical labs and dental offices are beginning to find the technology useful as well. Even homeowners are using consumer-based versions of dry steam machines to rid their houses of fleas and other pests without resorting to chemical treatments.

One litre of water produces 1600 litres of steam. This offers huge savings in water usage!