Medical lasers must be cooled either by premounted or portable chiller systems.
Laser systems continue to grow in application use throughout the medical industry. Applications for laser systems include diagnostic analysis systems, DNA sequencing systems, dental cleaning and surgery, skin care, eye surgery, tattoo removal, and much more. These systems commonly require cooling of the laser and other electronic components either by air flow on lower power laser systems, or by fluid circulation/chiller systems on higher power lasers. Higher power laser require an increased level of cooling capacity that results in systems that provide several gallons per minute of fluid circulation. This increased flow rate will maintain the laser and other electronics at the proper operating conditions.
Many medical laser OEMs build chiller systems on-board their laser systems creating a complete compact and portable unit. Others design their systems to be used in connection with portable chiller systems designed and developed by OEM chiller manufacturers. There are many OEM chiller manufacturers that provide these units in variable sizes to meet the specific needs of the laser system.
In general, both types of systems, either integrated on board or separate chiller systems, function in the same manner. These systems provide cooling to lasers and electronics by using fluids such as pure water, deionized water, mixtures of these with different forms of glycol, or similar thermal fluids. The fluids are circulated through a cooling plate or loop system that removes heat from these sensitive electronic devices.
Types of Pumps Used
The most common types of pumps effectively used for these systems are either AC-powered magnetic drive centrifugal pumps or DC-powered direct drive centrifugal pumps. (See Figure 1) Both of these pump designs utilize sealless technologies that provide long maintenance free life, quiet operation, and simple integration. The larger AC-powered magnet drive centrifugal pumps provide maximum flow rates and cooling power to the largest laser systems. The more compact design of the DC direct drive centrifugal pumps allow these pumps to be used in smaller laser or chiller systems where space and performance are critical considerations. DC direct drive pumps also operate with much lower power consumption, which allows OEMs to develop their systems with smaller, lower power components.
When designing a new laser system and considering an on-board or remote chiller approach, keep in mind that there are several pump options available to meet cooling requirements. AC or DC power, flow and pressure requirements, fluid medium and temperature range requirements, and overall size limitations all play significant roles in properly sizing the pump. The more complete this information is, the quicker and more effectively you and your pump supplier can work together to find the right solutions for your cooling application.
This article was written by Mike Ketchum, Director of OEM Sales, Marketing and Business Development, Iwaki America, Holliston, MA, which is a primary provider of both pump technologies. For more information, visit http://info.hotims.com/45603-165.