No matter how well a liquid filling machine is designed, incorporating electric heat to help control fluid viscosity is an important variable in most applications. Viscosity defines a fluid's resistance to flow. The higher the viscosity of a liquid, the thicker it is and the greater the resistance to flow. Conversely, lower viscosity means thinner liquid and less resistance to flow. Temperature will affect the viscosity of most materials. Heating up a fluid can reduce the viscosity, allowing the fluid to flow faster.
Recently, an Original Equipment Manufacturer (OEM) of liquid filling machines for the filling and packaging industry was experiencing viscosity issues in one of their product lines. Their customer, the end user, had specific flow rate parameters that the fluid filling machine was not meeting. The flow rate was too slow because the fluid was cooling down. This resulted in the viscosity of the fluid increasing, causing problems in their application. The OEM determined that the culprit was lost heat in the holding container, a hopper assembly. A hopper assembly, typically a large, inverted pyramidal or conical container, is used in industrial processes to hold particulate matter or flowable material of any sort such as, waxes, oils or viscous fluids and dispense them from the bottom when needed.
The OEM approached Tempco to find a heater suitable for the hopper assembly. Tempco suggested using silicone rubber heaters to add additional heat to the application. Surface heating is the preferred method of heating for this application since it's less likely to overheat the fluid in the hopper. Surface heating the external metal allows the material inside the hopper to be heated slowly. Two heaters were designed - a cylindrical heater to wrap around the top of the container and a larger, cone-shaped heater to wrap around the bottom funnel of the container.
To avoid PLC programming, both flexible heaters were designed to be controlled independently with surface mount thermostats rated at 70°-190°F that were set to reach the optimal temperature. Additional design features include:
- Mounting Method of boot hooks and springs so that the heaters can be easily removed
- Electrical termination of a simple, 120-volt plug
- Two different wattages were used for this application: 500 Watts for the larger heater and 250 watts for the smaller heater
- 120 Volts • UL recognized component heater
Tempco recommended an optimal, flexible heating solution for this application. We were able to quickly design and manufacture these silicone rubber heaters to help the OEM meet their customer's requirements.