The Posi-flate butterfly valve has been used for numerous applications in the milling and grain industry such as inlet and outlet valves on pneumatic transport vessels conveying seeds from a storage silo into weigh hoppers to fill 50 pound bags lines.

1. gases and slurry applications, the Posi-flate inflatable-seated
butterfly valve is unsurpassed. Standard valve sizes range from 2
inch (50mm) to 30 inch (800mm) and fit both ANSI and metric
flanges. A full line of actuators, limit switches and controls are
available to suit individual applications.
How the Posi-flate butterfly valve works
When the valve is closed and unsealed, as it rotates into the
closed position, the disc makes only casual contact with the seat,
reducing friction, wear and torque requirements. After the valve
is closed, the seat inflates against the disc providing more sealing
surface and an even pressure distribution against the disc. After
the valve is closed and sealed, the seat inflates against the disc
providing more sealing surface and an even pressure distribution
against the disc. When it is open and unsealed, before the valve
opens, the seat is first deflated. The disc is then free to rotate to the
open position.
Posi-flate case history
The Problem - A manufacturer of lawn care products, located in
Kansas, produces professional and consumer lawn fertilizer and
needed a reliable automated two-way diverter valve that would
provide a bubble tight seal. They were using a bucket elevator and
a manual two-way diverter valve to convey fine powered clay from
a rail car to two storage silos. The manual two-way diverter valve
was mounted about 50 feet in the air and the operators used cables
located at ground level to change positions of the two-way diverter
valve.
This manual cable setup was a maintenance issue because it
had a habit of sticking and many times slipping off the pulleys,
rendering the two-way diverter valve inoperable. Weather was also
U
sing the Posi-flate butterfly valves
boosts reliability and increases
production. Posi-flate butterfly
valves are also used as outlet valves
on bucket elevators diverting
fertilizer into different storage
silos, eliminating downtime for
unscheduled maintenance and lost
production. They are also used as
inlet valves on Extractor/Reactors discharging various dry organic
powders under a vacuum, which prevents harmful vapors from
escaping the Extractor/Reactors and reaching plant personnel.
Less friction, low torque, less wear, longer life
Posi-flate’s unique butterfly valve design uses air pressure
to expand the seat against the disc, providing even pressure
distribution for a bubble-tight seal, every time. Because the seat
makes only casual contact with the disc during valve opening and
closing, there is minimal disc impingement. This is in contrast
to conventional butterfly valves where disc impingement leads
to shaving of the seat, decreasing the overall performance and
valve life. Substantially less torque is required to open and close
the Posi-flate butterfly valve, thus a smaller actuator can be used
resulting in lower overall valve cost.
One to three million cycles
In actual comparison tests and documented field applications,
the Posi-flate butterfly valve outperformed all other valves. In
fact, a Posi-flate valve life of one to three million cycles, even in
extremely abrasive applications, is not uncommon. For dry solids,
CASE STUDY
76 | November 2016 - Milling and Grain
The use of Posi-flate
butterfly valves
The Posi-flate butterfly valve has been used
for numerous applications in the milling and
grain industry such as inlet and outlet valves
on pneumatic transport vessels conveying
seeds from a storage silo into weigh hoppers
to fill 50 pound bags lines.
F CASE STUDY

2. Performance Features:
• Heavy duty
• Inflatable seat compensates for disc and seat wear
• Longer valve life
• Minimal seat wear
• No disc impingement
• Ultra-low torque requirements
• Lower actuator costs
• More seal contact area
• Proven excellent for abrasive and dry solids
• Disc designed to prevent material buildup
• Double shaft seals
• Multiple bearings
• Fail-safe monitoring
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"Posi-flate butterfly
valves can be used as
outlet valves on bucket
elevators diverting
product into different
storage silos, eliminating
downtime for unscheduled
maintenance and lost
production"
a factor in the operation of this process since the two-way diverter
valve was exposed to the sometimes very harsh elements of wind,
rain, snow and sleet. Posi-flate butterfly valves were installed to
direct the flow from the bucket elevator to the two silos.
The Solution
Plant personnel noticed an ad for the Posi-flate inflatable
seated butterfly valve in a monthly magazine publication.
After looking at their problems further, management became
convinced that the Posi-flate butterfly valve with its automated
controls could solve their maintenance issues, provide improved
reliability and give them a much better seal with higher
productivity.
The Results
After installing two Posi-flate butterfly valves, the manufacturer was
able to eliminate downtime that resulted from maintenance issues along
with the manual errors made previously by plant personnel. Since the
Posi-flate valves create a bubble tight seal, the customer does not have
to worry about lost production or unscheduled maintenance.After four
years of operation, plant management has stated that the Posi-flate
butterfly valves have operated without any maintenance issues and they
have not had to purchase any replacement parts whatsoever, saving
money and downtime.
Plant personnel believe that the Posi-flate butterfly valves are
ideally suited for what they feel is a very abrasive application. In
addition, the manufacturer has since decided to replace all of the
existing manual two-way diverter valves with Posi-flate butterfly
valves.
Milling and Grain - November 2016 | 77
CASE STUDY F