The idea is not a new one.The concept of an extraction machine so large and heavy that it is left in a vehicle and operated with long hoses has been successfully employed for over 30 years. Until recently, the immense labor saving benefit of these powerful cleaning units was not realized by any but the largest building service contractors.

Truck mounted carpet cleaning systems are primarily purchased by professional carpet cleaners. These owner/operators demand and receive equipment which can cut time on the job, perform deeper, more thorough cleaning, and dry faster. What these professional cleaners get, along with the benefits, are machines that are complex and often unreliable if not properly designed. The trade-off is still good for them and truck mounts today dominate the professional cleaning industry.

Years of experience have elevated truck mount technology and resulted in substantial gains in simplicity and reliability. Truck mounts are now available that can better withstand the abuse of multiple operators and can be operated by less skilled employees.

Recent developments in sound suppression technology have resulted in quiet operating machines capable of working without undue disturbance to neighbors or occupants. These improvements make truckmounts much more effective.

Two basic types

All truckmounts are not alike. Choices must be made based on features and benefits to meet your exact needs. Initially, truck mounted carpet cleaning machines can be divided into two basic types:

Slide-in truck mounts -- Referred to as "slide-in" units because they can be put into many different vehicles and do not require power from the vehicle. This type of unit is powered by its own engine and is built within a frame or chassis that is bolted into the vehicle. The advantages are: It has flexibility in the type and age of the vehicle used, is easy to transfer from one vehicle to another, and has slightly lower gas consumption. The disadvantages are: It consumes more cargo space, is more complex to operate, and has higher maintenance requirements and the power plant can be less reliable.

Van-powered truck mounts -- So named because this type of machine is powered by the engine of the vehicle itself. This is accomplished with a power transfer shaft that is belt-driven and extends from the front of the engine, back into the interior of the vehicle where it drives the machine components. An electric clutch similar to that used on the vehicle's air conditioning, controls the on/off function of the unit. The advantages are: It is very compact, consumes less interior space, requires less maintenance, is simpler to operate, and is more reliable. The disadvantages are: It has rigid requirements regarding type and age of vehicle, is more difficult to transfer to another vehicle, and has higher gas consumption.

Technical considerations

Although truck mounts come in all shapes and sizes, they share four key components, common to all units:

Motive power -- A key benefit of a truck mount is that it is self-contained. It powers itself, without any outside connection (e.g., electricity) required. This adds speed, flexibility, and power. Most truck mounts are gasoline or propane powered. Engines used in slide-in units are typically 16 hp to 24 hp and can be air-cooled or water-cooled. Van-powered units are driven by the vehicle's engine.

Vacuum power -- The key to success in a truck mount can be found here. Truck mounts use positive displacement vacuum pumps that enable them to clean several hundred feet from the unit with minimal loss of power. Portable, electric-powered extraction equipment, on the other hand, typically loses too much power to operate in this manner. Although CFM (cubic feet per minute) and vacuum lift figures sometimes sound sufficient on larger portables, the centrifugal vacuum systems used in these machines cannot perform as well at long hose lengths.

There is a direct correlation between vacuum power at the wand and the efficiency of water recovery. Recently, the focus of performance has been brought to bear more on the amount of air being moved than the lift shown on the gauge. Air movement is expressed as CFM and lift as inches of mercury (1" Hg equals 13.5" water lift). High performance truckmounts will be capable of moving at least 290 CFM and larger units as much as 405 CFM. These impressive vacuum levels result in significantly faster cleaning and are responsible for much less residual water in the carpet after cleaning.

[ Read more about vacuums: Myths, Fables & Facts About Vacuum Systems ]

Water power -- The water pumping systems built into truck mounts are high pressure systems which are generally capable of over 1,000 psi. These systems are generally operated at 300-400 psi and when properly engineered, this high pressure water increases cleaning power without harm to the carpet. One key to successfully using high pressure water in a truckmount is that it is well balanced by the capability of the unit's vacuum system to remove the water as fast as it is applied. The pressures employed by portable units are typically in the 40-100 psi range and are correspondingly less aggressive in the cleaning process.

Water temperature -- Perhaps the most significant benefit to cleaning with truck mounted equipment is the high water temperatures these units can sustain. It is a commonly accepted fact that water cleans better as temperature is increased, as long as the temperature does not exceed a level safe for the fabric. With heat, the activity of cleaning chemicals is dramatically increased, which improves both the speed of cleaning and the effectiveness of soil removal. Some soils, particularly greasy soils, become particularly easy to remove with elevated temperatures. A well-engineered truck mounted system, supplied with cold water, is capable of producing a constant, reliable water temperature of 190-240 degrees F. This is the temperature before the water experiences the normal heat losses of the system. The most substantial heat reduction is at the jet tip where the water is atomized and sprayed into the air, where it can lose as much as 30 degrees instantly.

As a result of the system heat losses, the temperature of the water will end up at about 150-180 degrees F., which is safe for any carpet manufactured. Portable extraction equipment does not share the same cleaning advantage of heat. Starting at about 100-120 degrees, when the heat losses occur, the cleaning temperature drops to about 100 degrees or less.

Efforts to supplement heat loss through the use of electric heaters are only minimally effective and can't duplicate the heat rise achieved by a truck mount. The amount of thermal energy available from 20 amps at 120 volts may be sufficient to raise water temperature a few degrees but will not achieve the 100+ degree heat rise that truck mounts enjoy.

[ Read more about temperature: All Heat Exchange Truckmounts Are Not Created Equal ]

More to consider

Any organization considering the purchase of a truck mounted carpet cleaning system should consider several other factors that are not technical in nature. These considerations have more to do with the smooth, consistent operation of the equipment in years to come.

Warranty -- Extremely important in truck mount ownership is the coverage provided by the manufacturer against defective or failed parts. The stress of heat and vibration can take its toll and early component replacement could quickly eat up any initial savings in purchase price. The minimum standard of most manufacturers is a one-year warranty. Careful attention should be given to items excluded from warranty protection. These excluded items are often the most likely to give trouble.

Installation, maintenance & repair -- A truck mount should always be professionally installed. Safety requires that the machine be securely mounted in the van and the fuel system be established by a trained technician. When purchasing a truck mount, remember that you are also buying into a long-term maintenance and repair relationship with the company you bought it from.

Your truck mount will need mechanical attention. Satisfy yourself as to the availability of service and that the degree of expertise is adequate. Inquire about the extent of local stocking for repair parts. Many truck mount manufacturers have not developed consistent, reliable service in all areas. The presence of a local distributor, who stocks repair parts and maintains a service shop, should be considered an important plus.

Product quality -- Although all truck mounts perform the same basic function, quality can vary greatly. To understand the concept of quality, consider the case of automobiles. If you examine a Kia and a Lexus, you would find that they both perform the same basic transportation function. They are both capable of going down the road at 80 mph, but there's no comparison of how they function at that speed, their ultimate reliability when asked to perform day in and day out, and the life expectancy of each. Truck mounts vary as greatly. The differences are there to see through trained eyes.

Investment or expense?

If you have sufficient amounts of carpet to clean, a truck mount will not cost money, it will save money. In a labor-intensive job like cleaning carpets, a powerful machine, which only requires fresh, cold water, and delivers fast, powerful cleaning at 2-3 times the speed of portable systems, will justify its own existence and more. Positive cash flow, where savings in labor exceed the costs of the equipment, can be expected from the beginning. It is for these reasons that over the last 30 years, truck mounted carpet cleaning systems have firmly established themselves as the system of choice in volume carpet cleaning environments.

Steve Brandt
HydraMaster Corporation

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