NF (MR and LR also food-grade for other food-processing applications)
Since the mid-1990s, food-grade thermal fluids have been the heating technology of choice in continuous fryers, high-volume ovens and belt grills. Paratherm NF® heat transfer fluid has been specified and maintained in these applications from the very beginning.
Paratherm reduces downtime for seafood, meat and poultry further processors through a combination of proactive, regular fluid analysis checkups, preventive maintenance contact, and a network of stocking warehouses and distributors throughout North America, and increasingly, around the world as well. In order to deliver the fluid quickly for routine orders, and extremely quickly in the event of an equipment or plant emergency.
Paratherm NF® Heat Transfer Fluid
- NSF HT-1 Food-Grade (Non-USA Food-Grade Certs available upon request)
- Maximum Film Temperature, 650 °F
- Available in 5 gallon pails, 55 gallon drums, 1000 L and 330 gallon disposable totes, and in bulk by ocean flexitank and tankwagon.
Heat Transfer Fluid Systems for Poultry Plants
Thermal Fluid Systems are now the standard for new facilities and line upgrades in poultry plants. Thermal fluid systems are being employed in large scale facilities all over the world. The world’s largest poultry further processor almost exclusively uses thermal fluid in order to heat the fryers in its 20+ plants. The operation uses ovens and fryers to par fry and bake various meat, sausage, poultry and Mexican food products.
The Safety Benefit
The plants range in size form 25-75,000 square feet each, and yield millions of pounds of fried food a month. Only a few lines are still making use of direct fired heating, simply because they have not had the opportunity to switch them over to thermal fluids yet. Safety is considered to be the biggest benefit of thermal fluids. With direct fire, the risk of fire is great and the danger and stress to employees is high.
Thermal fluids majorly reduce the risk of fire if the systems are appropriately specified and maintained. With increased safety comes lower insurance premiums and claims, and OSHA inspections are made considerably easier due to the safer working environments.
Precise Temperature Control
Another benefit to using thermal fluids to heat the frying systems refers to precise temperature control. The frying oil is controlled within + or – 1 °F, which decreases product waste from direct frying by 1%. Most frying plants work on an operating temperature of 350-400 °F with cooking times of about 15 seconds. In order to maintain this temperature, a boiler which can range from 800,000 to 1.2 million BTUs is set up in a heater room and set between 530-550 °F. The fluid velocity in heater coils is about 10 feet per second, so the fluid keeps moving to maintain consistent temperatures.
Having the boiler in a separate room helps in creating a safer working environment. Maintenance can be effortlessly performed without interfering with the line.
No Fuel Odor and Food Safe
Employees enjoy thermal fluid systems as they eliminate fuel odor in plants, not to mention the possibility of explosions from open flames. This is a major benefit over direct fired systems.
An instant email of the Paratherm NF® Food-Grade Heat Transfer Fluid product information, safety data and physical/thermal properties data can be obtained through email.
With Paratherm NF even a leak is not considered to be a big problem. Extensive toxicity tests have been conducted on lab rats, and not one was harmed by ingesting the fluids, a testament to the “food safe” nature of the product. The food could still be used for animal feed even if a system were to leak into the frying oil, or the processed product would get HTF splattered on it.
Maintenance and Fire Prevention
With Heat Transfer Fluids, performance and safety are majorly improved through proper maintenance. A program of weekly or daily checks keeps systems running at their best.
Placing the boiler in a separate room aids in creating a safer working environment and maintenance can be easily carried out without interfering with the line.
Keeping the Y strainer cleaned will extend the life of the fluid charge, and help the system operate smoothly.
If sludge is present, side stream filters will help in removing sludge over a period of time during continuous operation.
Examine sources of potential leaks such as flanges, valves, weldments that see stress, threaded fittings and instrument ports. Smoke is considered to be a sure sign that fluid is leaking.
Check the system vent. Steam or mist coming from the vent can signal water in the system or that the fluid is decomposing. If steam is coming out, the catch drum at the end of the line from the expansion tank relief valve must be checked. If it contains liquid, examine why, because hot fluid splashing into a drum partially filled with water can create a cloud of hot oil mist that can easily ignite. This could cause an explosion and fire.
Key Installation and Maintenance Considerations to Prevent Fire
- Do not use threaded fittings. Due to a huge degree of thermal expansion and contraction: leakage is almost guaranteed.
- Use only closed-cell insulation in leak prone areas such as: pumps, valves, flanges and instrument ports.
- For valve stems bellows seals are the most extensively used.
- Graphite sheet gaskets are considered to be the best choice for flanges.
- Follow manufacturers recommended torque and tightening sequence when installing gaskets.
- During construction or installation four areas should always be taken into account: system cleanliness, system tightness, component orientation and allowance for thermal expansion and contraction.
- System Cleanliness
- Assure the system is dry and clean. “Hard” contamination must be removed as the system is assembled. Hard contamination such as mill scale, dirt and weld splatter/slag can be controlled by properly cleaning the Y strainer.
- Component Orientation
- Locate expansion tanks far enough away from heaters in vented systems, so they run at no more than 150 °F.
- Warm up valves should generally be closed. The fluid can severely oxidize if comes in contact with the air and it is run hot.
- Valves should be mounted stem side, so that that leakage from the bonnet gasketing is less likely to enter nearby porous insulation.
- Gaskets should be the type that can flex with the thermal expansions of the system.
- Porous insulation should be kept away from possible leak points.
- System Tightness
- Once construction is complete, allow for pressure testing at potential leak points using simple soap-bubble detection methods. When the system is charged with heat transfer fluid, slowly circulate the system bringing the temperature up to 220 °F, release steam and liquid, and then resume gradually bringing up to the operating temperature.
- Allowance for Expansion and Contraction
- Average Thermal Fluid systems experience extensive temperature swings.
- Different metals expand and then contract at different rates.
- If allowances are not made, welds and piping may not hold up, and can lead to showers of hot fluid.
This information has been sourced, reviewed and adapted from materials provided by Paratherm.
For more information on this source, please visit Paratherm.