The paper producer may turn to S. Bederian Technical Service LLC for analysis of paper machine threading difficulties or service and optimization of existing tail threading equipment.
Formed in 2009 S. Bederian Technical Service LLC is a sole-proprietorship for an acknowledged process expert in tail-threading of paper-making machinery. Mr. Bederian has over 40-years of experience to the paper machine industry.
In a career beginning at paper machine supplier Sandy Hill Corporation and continuing to the present day Mr. Bederian has initiated machine design, development and control in paper-production and converting machines.
Mr. Bederian has been factory-trained and has 18-years field experience in the service and application of vacuum conveyor and carrier-rope tail threading systems as supplied by Fibron™ Machine Corporation.
Mr. Bederian has held long-term membership of several premier technical organizations:
Mr. Bederian is a degreed engineer and is registered as a Professional Engineer with the State of New York.
Mr. Bederian recognizes the importance of safe work practices. He maintains current OSHA training and TAPPI-Safe certificates.
Located in upstate New York near the traditional paper making areas of the Adirondack Mountains S. Bederian Technical Service is within a day's drive of mills from Maine through Pennsylvania. Albany International Airport is nearby. Flight schedules are frequent providing reasonable connections to locations throughout the Western hemisphere.
Under ideal situations a paper machine can produce a web of paper at high speed 24 hours a day for extended periods between wash-ups or shutdowns. Sheet breaks do occur, making it necessary to thread the sheet through the machine. During sheet breaks there can be added operator safety concerns. Proper use of threading systems can limit the risk exposure for machine operators. Reducing the time necessary to re-thread the machine or allowing the machine to more quickly return “on-grade” will reduce operator fatigue and can directly impact the overall machine efficiency.
Threading of a paper machine is done by cutting a narrow tail from the running web. It is this tail that is passed through the machine a section at a time. Once the narrow tail is though a section it is opened out to full width and the process is repeated for the next section.
History: In years past it was common for tail-threading to be done completely by hand; operators would climb over or crawl under the paper machine and pass the paper-tail one to another around the various rotating equipment. Photos from the late 1800’s usually show the machine and the entire crew. Close inspection of these photos would find several operators as barefoot (making for safer climbing on a slippery machine) or with missing digits.
Rope threading was introduced to reduce risk exposure as production speeds increased. Multiple tail-carrying ropes (usually 2 but sometimes 3) are passed through the machine. The tail is captured between the ropes and carried through a section. The rope system is mechanically complex and its effective adjustment and maintenance can directly affect the machine efficiency. Section to sections transfers were still done by hand requiring a skilled operator with precision eye-hand co-ordination as rope systems have their own unique safety concerns. Modern machine speeds have increased to the point to make a hand-pass transfer into a rope-nip a safety issue to note.
Air-trays were introduced to mechanically transfer the tail from section to section or to offer rope-less section threading. When used within a narrow window of operation, air-trays can be quite effective. Many machinery suppliers produced flat-tray type devices such as Mount Hope among others, tubular air-trays were a feature of Beloit light-weight machines. Air-tray systems can be challenged by large changes in machine speed, sheet weight or moisture.
Threading conveyors for mechanical tail transfer appeared in the mid-1970’s produced by Durand Machine of British Columbia, Canada. This device uses vacuum to attach the tail to a conveyor and can transport the tail more effectively at the highest machine speeds and over a wider range of sheet weights. These machines often require sophisticated control. This style equipment is in use from various sources: Fibron™, FoilForce™ and SurePass™ among others.
Most machines in production today incorporate some or all of the above threading styles.
Control of threading equipment can range from simple hand valves and hard-wired push-buttons to complex semi-robotic operation via digital machine process control. It takes an experienced hand to assist in the troubleshooting and modification of controls.
Fibron is a registered trademark of Voith Paper Corp.
FoilForce is a registered trademark of Metso Paper Corp.
SurePass is a registered trademark of Andritz-Paperchine LLC
On-site service supervision supplements the mill maintenance effort to re-establish the original tail-threading operation.
The service interval recommended for trained expert care by most suppliers is 12-months. The service technician is usually brought on-site during shutdown. His experience and knowledge contributes to repair, resetting and fine-tuning of the existing threading equipment.
A written service report is made for each customer visit.
Training can be informal such as having mill maintenance “shadow” the service tech or with operators at machine-side in question and answer. Formal classroom-style training can be arranged.
Mechanical changes to machine sections can affect operation and arrangement of existing threading equipment. Some changes may be accomplished with the equipment remaining in-machine. Others may require removal, rework and re-installation. Some section changes may void the usefulness of the existing equipment altogether. S. Bederian Technical Service LLC can assist the mill to plan and execute the rework or salvage of existing equipment.
Over time most paper machines experience significant process changes as the mix of grades is ever evolving. Production and product demands affect machine speed, basis weights and trim. Often times existing threading equipment has been designed and tuned to perform at best efficiency at target grades that no longer represent the machine production standard. Where machines with a narrow grade range may benefit from a standard service call, machines with a wide grade range should consider a multi-visit optimization service to observe threading performance over long-term and multiple grades.
New threading equipment usually has the installation service-supervision priced as a break-out. A mill may wish for the purpose of continuity or economy to consider S. Bederian Technical Service LLC to provide or supplement this service.
This service involves a detailed on-site inspection of the existing machine and observation of current threading practice. A site visit is scheduled to include a shut-down day followed by a machine re-start.
A static inspection provides physical and mechanical details, observation of the re-start provides detail of the threading process and efficiency, interviews of operating personnel provides the long-term history of threading experience.
A detailed written report is produced for the customer. This report compiles the data from the site visit and establishes the current state of threading for the machine. It identifies:
Using this report the customer may establish a path to improved machine efficiency.
S. Bederian Technical Service LLC is available to assist the customer to achieve these goals.