Keep Airflow to a Minimum

Air flowing over exposed solvent will accelerate evaporation and is one of the most significant ways to evaporate a solvent.

• Avoid drafts in the degreasing equipment area. You can test for drafts by holding a strip of tissue paper over the evaporating degreaser; movement indicates air flow. Avoid placing fans or mechanical ventilation in proximity to the degreasing unit and place it in an undisturbed area away from doors and open windows. Use baffles as necessary to divert drafts and air currents from the area.
• Don’t spray above the vapor zone. This admixes vapor and air, which leads to solvent loss.

In open-top degreasers, significant solvent loss can occur through the open top of the unit. The following precautions can help prevent this from happening:

• Put lids on tanks. Cover tanks when not in use. Covers that slide off and on horizontally disturb the vapor less than ones that hinge vertically. If you can, use silhouette entry covers that stay in place during use; this can reduce relative evaporation rates of solvents by up to 55 percent.
• Add secondary cooling coils above the condenser coils. This creates an additional vapor loss barrier.
• Increase freeboard space. Aim for 100 percent or higher freeboard to significantly reduce solvent loss.

Handle the Work Properly

Solvent can easily escape as work moves through the degreasing unit. Much of this loss can be prevented through careful handling.

• Minimize startup/shutdown. Air is expelled as the unit is activated, and takes a small amount of vapor with it. Consolidate cleaning tasks to favor large batches over small ones.
• Move parts slowly. Rapid movement introduces air into the system. Automatic hoists are an excellent preventative solution.
• Don’t overload the basket. Loads that are too big or too heavy disturb the vapor blanket and exacerbate solvent loss.
• Allow sufficient dwell time. Leave the work in the vapor zone until temperatures have equalized to prevent drag-out and evaporation of liquid solvent.

Handle the Solvent Properly

• Avoid pouring the solvent from buckets or drums. Instead, pump it through a hose, making sure the fill connection is submerged to minimize turbulence.
• Prevent storage leaks. If you have to store partially used drums of solvent, make sure the lids are tightly sealed, and store drums bung end up to prevent spillage through leaky bungs.
• Do not add cold solvent to a degreaser as it is operating. This can disturb the vapor blanket. Instead, top off solvent by adding to the rinse sump when the unit has cooled.

Perform Regular Cleaning and Maintenance

Keeping any type of equipment clean and in good working order is critical to maximizing its efficiency. Degreasing equipment is no exception, and regular maintenance will help keep otherwise unavoidable solvent loss to a minimum.

Do not attempt to clean a solvent degreaser yourself unless you have people on staff who are trained and qualified to do the job. Also, be aware that compliance measures may require you to have a contained space permit and/or measure solvent fumes with a ppm meter.

Enviro Tech offers a full range of vapor degreaser cleanout services, including regular maintenance services, emergency service and replacement parts. For more information or to request a quote, contact us here — or give us a call at 708-343-6641.