When a customer requested our advice on the most effective long-lasting seal technology for steam tube dryers in petrochemical applications, our application engineers designed and ran a Seal Test Assembly to generate live test data to inform and confirm their recommendations.

To gather relevant data in a controlled environment, our engineers and fabricators built a scale-model steam tube dryer seal assembly in our own test lab.

For this test seal, we decided to use chevron V-packing in lieu of the traditional square packing. Whereas square-packing is made from woven PTFE and integrated graphite, the chevron V-packing is made of extruded polymer – which is optimally suited for maximal segregation of external oxygen from entering the internal dryer’s closed inert atmosphere. The V-packing is housed within a machined, cooling-jacketed, stuffing box.

To simulate a real processing environment, we mounted the test unit on a slew bearing, and allowed to float with the rotating seal surface using adjustable die springs.

Electrodes were attached to induce heat and ports were used to pressurize the system up to 1 PSIG, and gauges were installed and monitored.

The test unit operated continuously over the course of three years with only minimal tweaking such as bearing lubrication. The test data confirmed the effectiveness of using the longer life chevron V-packing on both the feed and discharge end of central discharge dryers in petrochemical applications. They significantly limit the leakage of ambient atmosphere or vapors and prevent the intake of external oxygen.

Why Central Discharge?

The Louisville Dryer “CS” Central Discharge Steam Tube Dryer design was developed for solvent extraction, and processing materials wetted with liquids other than water, which must be processed in an inert atmosphere and where the vapors must be captured and not allowed to escape to atmosphere.

Many materials at some point in their manufacture are volatile and reactive with O2 which can degrade the product, ignite, or explode. Some materials are processed with acids or volatile liquids where if leaked to atmosphere can cause injury to personnel, or damage to surrounding equipment or facilities.

The Louisville Dryer “CS” Central Discharge Steam Tube Dryer reduces the required sealing area by conveying the dried product through the center of the steam chest with helical discharge flights, into a very efficiently sealed discharge housing. The “CS” sealing mechanism is comprised of a machined mechanical seal and packing assembly which allows for static and dynamic purging with a variety of process gases and/or steam. Cooling water can be used in applications where required, as well as grease purge glands.

The Louisville Dryer “CS” seal design can be designed for process side pressures up to 1.5 PSIG, and in a number of carbon steel alloys and nickel alloys for highly corrosive applications. They are most effective when installed on both the feed end of the dryer and the discharge end.

Test Your Product in Louisville Dryer Company’s Test Lab

Curious how testing your product in our production-worthy scaled dryers in our own leading-edge research and development lab can benefit your company? We have manufactured coolers to help companies develop new products such as wood composite, airbag propellant, rocket fuel, algae-derived oils and others. Our test engineers can help determine best processes and equipment for your team. Call us today at 800-735-3163.