How To Get the Best Temperature Control
In general, locate your circulator on a level surface free from drafts and direct sunlight. It is also imperative to avoid locations where corrosive fumes, moisture or dust are present. Also, make sure that there is adequate space around the instrument to allow for good airflow. Ideally, it is best to leave at least 8" of open space around the instrument. This is particularly important for refrigerated units.
Protect against voltage drops by using properly grounded power outlets wired with 14 gauge or larger diameter wire. Locate the circulator as close to the power outlet as possible.
To achieve the best temperature control, use the largest diameter tubing possible for maximum flow. Flow restrictions will adversely affect cooling performance. Always insulate the tubing between the circulator and the external application. Choose the fluid with the lowest viscosity at the selected operating temperature range, and keep the reservoir covered. Consider using an external 100 ohm platinum RTD probe for optimal temperature control of external applications.
Below Ambient Temperature Applications. When considering fluids for use in applications below ambient temperature, there are several other precautions that should be taken.
The three primary considerations when choosing a fluid for your applications are flashpoint, viscosity and the compatibility of the fluid with the circulator components as well as the tubing material being used. Because most synthetic fluids are hygroscopic, i.e., they have a tendency to absorb water, the use of a condensation trap is recommended to keep moisture from forming in the bath reservoir at subambient temperatures.
High Temperature Precautions. In applications with high temperatures, follow these precautions.
Select a fluid with a flashpoint well above the operating temperature. Silicone oils are preferred over mineral oils, which may cause excessive fuming or can more easily catch fire. Consider placing the application in a fume hood because even silicone oils will release fumes at high temperatures.
In addition, keep these application tips in mind when using simple water baths. Heat loss from water vapor may cause poor temperature stability. Use a bath cover or floating hollow balls to help cut down on heat loss and vapors. Fluid lost from vapor will have to be replaced frequently.
Sidebar: For the best temperature control . . .
In addition, if your application operates at high temperatures, remember to:
- Use a fluid with a flashpoint well above the desired operating temperature.
- Consider placing high temperature applications in a fume hood.
- Use a bath cover or hollow balls with water baths to lessen water vapor loss.