Is my washer-extractor’s loading capacity set in stone? I mean, can I fudge a little and load heavier to get more work through when we’re under the gun? What’ll happen to my wash quality if I overload (or underload) a machine? Is overloading worse than underloading, or vice versa?
EQUIPMENT DISTRIBUTION: Curtis McDowell is the general manager and head of OPL sales for Super Laundry dba Laundry City Equipment, a distributor of commercial and industrial laundry equipment. He has more than 17 years of industry experience, including service and sales.
I’ve been asked these questions many times, particularly during startups. You first need to understand how the manufacturer calculates the washer’s capacity.
It’s widely accepted that 1 cubic foot of cylinder volume equals approximately 6.5 pounds of soiled laundry. If all of the soiled items weighed the same, you could just weigh every load with a scale and fill the washer to its proper capacity. But, as we all know, the mass of feathers is not equal to that of bowling balls.
To explain how much laundry equals a properly loaded washer, I need to address the mechanics of a washer-extractor. With the absence of an agitator, the front-load washer relies on picking up the load, with ribs inside the cylinder, and dropping it. This causes the water and chemicals to penetrate the goods and remove the soil.
Overloading the cylinder decreases the amount of drop and greatly reduces the washer’s effectiveness in getting items clean. Underloading the cylinder can cause the load to roll on itself, with the same results in quality.
If you’re utilizing automatic chemical injection, your wash formulas are programmed to add a predetermined amount of chemicals into the wash cylinder at various points during the cycle. These amounts are calculated for a properly sized wash load.
When you overload, you decrease the effectiveness of the chemicals to do their job. When you underload, you’re subjecting the goods to higher concentrations of chemicals than necessary. This results in residual carryover that could shorten product life as well as cause health concerns for people with sensitive skin.
While loading your washer a little heavier when you’re under the gun may seem like a good idea, the results could come back to haunt you. Consistently overloading a washer can cause bearings, the cylinder shaft and the frame to wear prematurely. Underloading can greatly exacerbate the situation.
When a machine goes into high-speed extract, it’s imperative that the load is evenly distributed around the cylinder. Underloading greatly increases the risk of not achieving this. It causes excessive vibration and force to be transmitted through the machine and into the foundation.
When deciding which is worse, or better, overloading or underloading, I would say neither. The only winning move is to load the washer-extractor to its recommended capacity.
TECHNICAL SUPPORT: Jim Mitchell, principal technical support specialist, is a 26-year Ecolab veteran. He’s currently its OPL lead in providing technical support to field associates. He edits Institutional Technical Digest, a monthly publication reaching 2,800 employees.
Is your washer-extractor’s loading capacity set in stone? Yes and no. The capacity rating on a washer is usually relating to the dry weight of linen. However, depending on the washer’s cylinder size and preset water levels, loading a 100-pound washer with 100 pounds of dry linen may result in a machine that is overloaded.
Weighing linen prior to loading is a good practice, but can be misleading. One must consider the weight from any soil or liquid the linen absorbed prior to washing. One hundred pounds of sheets will create more actual linen volume in the washer than 100 pounds of heavily soiled diapers or pads.
Also, the amount of linen loaded into a washer is in direct proportion to the preset water levels. Loading 90 pounds of linen into a 100-pound washer is a good practice, unless the machine’s water levels are too low.
Here’s a simple guideline to consider for loading most washer-extractors on the market today:
• Load the machine to 90% of the rated capacity.
• Make sure all water levels are set correctly.
• Do a visual observation of the wash wheel. After the load is saturated with water and the wheel is rotating clockwise, the linen should “break” from about 11 o’clock to 4 o’clock. This provides the necessary mechanical action for soil removal.
Providing the water levels are set correctly, this procedure should allow for the necessary flushing and rinsing of linen, as well as maximizing the performance of cleaning chemistry.
Whenever possible, don’t fudge! You will probably pay the price with rejects and rewashes. Overloading the wheel can lead to a number of washing deficiencies:
• Poor preflushing of water-soluble soils.
• Poor transfer of soils to drain once they are lifted from fabrics by cleaning chemicals.
• Insufficient distribution of cleaning chemicals.
• Poor rinsing of chemistry.
A washer that is underloaded can also create a number of issues:
• Poor mechanical action during the washing process. (Linens have a tendency to float in an underloaded wheel.)
• An out-of-balance condition when the washer goes into extract.
• A high cost per load in terms of labor, chemistry and utilities.
Underloading a washer usually has little effect on results, although with less cumulative soil in the washer, titrations/concentrations of chemistry can be elevated and lead to linen degradation. Consistently overloading a washer can cause short-term and long-term quality issues.
In the short term, you’ll find:
• Residual soil – food, urine, feces, hair, etc. – tied up in fabrics.
• A high reject rate in terms of bleachable stains.
• Residual offensive odors are left in fabrics.
• A high reject and rewash rate.
Over the long haul, you’ll find:
• High linen replacement costs due to rag-outs.
• The graying of white linens.
• All linen can develop a harsh or rough feel.
• Increasing chemical costs as more chemistry is added to formulas in an attempt to reclaim the damaged goods. Unhappy customers!
In terms of linen quality, overloading is far worse than underloading. In terms of total operating costs (with the exception of linen replacement), underloading is worse.