Freeze dryer or lyophilizer applications have long been debilitating to rotary vane vacuum pumps. The high concentrations of corrosive vapors that are pulled into the pump quickly condense and combine with the pump oil to form a thick molasses type substance that kills most traditional rotary vane pumps. In order to keep these pumps operational, the end user must change the oil and clean the oil chamber on a very regular basis. The continuous maintenance and disposal of the hazardous waste oil is both expensive and inconvenient. Even with regular maintenance, many rotary vane pumps still don’t live up to the end user’s expectations.
The new Cole-Parmer Rotary Vacuum Pump addresses the problems associated with difficult freeze dryer applications. These pumps combine the low base pressure and high pumping speeds of a rotary vane pump with the high chemical resistance of a PTFE diaphragm pump. The diaphragm pump holds a vacuum on the head space of the rotary vane pump. As the corrosive vapors are brought into the rotary vane pump, the diaphragm pump pulls them on through before they can condense in the oil. A pair of condensers on the outlet of the pump act to catch much of the solvents that have been evaporated, resulting in cleaner, longer lasting oil in the rotary vane pump.
larger view This combination pump has proven to be quite effective in corrosive freeze dryer applications. ARUP Laboratories in Salt Lake City, Utah has been using the 72226-70 Cole-Parmer Rotary Vacuum Pump on one of their existing freeze dryer units for the past several months. This particular freeze dryer is in use nearly 24 hours a day, 7 days a week as they continuously process patient samples. As a result of the high usage, ARUP’s Bioengineering Department had to change the oil in their previous pump on a monthly basis; a four-to five-hour flushing and cleaning process that resulted in costly downtime for the freeze dryer. They have now been operating the new pump for over six months without needing a single oil change. Expectations for oil maintenance on the Cole-Parmer Combination Vacuum Pump in this application is once per year, greatly reducing the maintenance costs associated with the freeze dryer.
If we assume some very reasonable values for maintenance costs, we can calculate the savings ARUP has realized through the addition of the Cole-Parmer Combination Vacuum Pump versus the standard rotary vane pump they previously used.
Maintenance Costs
Standard Rotary Vane Pump:
Bioengineering Labor: $100 / Hour
Labor and Downtime: 4 Hours
Downtime Cost to Production: $150/Hour
Cost of Replacement Oil: $15
Cost of Oil Disposal: $10
Annual Number of Oil Changes: 12
(($100 x 4) + ($150 x 4) + $15 + $10) x 12 = $12,300 / yr | Cole-Parmer Pump (72226-70):
Bioengineering Labor: $100 / Hour
Labor and Downtime: 4 Hours
Downtime Cost to Production: $150/Hour
Cost of Replacement Oil: $15
Cost of Oil Disposal: $10
Annual Number of Oil Changes: 1
(($100 x 4) + ($150 x 4) + $15 + $10) x 1 = $1,025 / yr |
With a purchase price of $5,031, the Cole-Parmer Rotary Vacuum Pump (72226-70) has a payoff of less than 6 months through the reduction in maintenance costs. The increased life of the oil also results in a longer lasting pump, which allows Cole-Parmer to safely offer a two year-warranty with the Cole-Parmer 72226-60, -65, -70, -75, -85 vacuum pumps.