Friday, October 31, 2014

Sharpe Hyflo Impellers

A line of hydrofoil impellers that incorporate a split-hub design which is stronger, more adjustable, and easier to install and remove than conventional one-piece or bolted-blade impellers is available from Sharpe Mixers,

Inc. of Seattle, Washington.

Sharpe HYFLO Impellers feature four blades with a narrow, low-pitch section at the tip where the speed is fastest and a wider, higher-pitch section near the hub where it is slower for maximum efficiency. In 24” dia. and larger sizes, the blades are welded directly to a split-hub that can be attached anywhere on a shaft without a keyway, and is easy to adjust or remove.

Available in industrial and sanitary versions, the split-hub eliminates the need to cut and weaken a shaft with a keyway. For high torque applications,

Sharpe HYFLO Impellers’ fail-safe operation is achieved by welding torque pins to the shaft which fit into matching holes on the split-hub’s bore.

Suitable for new equipment and retrofit on existing agitators, impellers can be made from 316SS to titanium and other alloys in 3” to 210” dia. sizes.
 
Sharpe HYFLO Impellers with split-hubs are priced according to material, size, and quantity. Pricing is available upon request. One-piece impellers are also offered.
 
Submitted by,
Fred DeCicco

Tuesday, October 21, 2014

Understanding Motor Overloads Caused by Low Voltage

Motor overloads are a common industrial problem when motors are not protected adequately.  This can include incorrectly sized circuit breakers or no circuit panel at all.  It can also be due to an undervoltage situation.

The definition of undervoltage is the condition when the applied voltage drops to 90% less than the motor's rated voltage for at least 1 minute.  Low-voltage situations occur when the voltage demand exceeds what the line can deliver.  This can be caused by a number of reasons; a transformer can act as a choke, restricting the amount of total power that gets through when demand is high.  Maybe the demand from newly installed equipment sharing the same line exceeds what the line can deliver.  In some cases, a motor with a long cable run can drop the voltage on a circuit, resulting in low voltage to that motor.  Brief low-voltage conditions can occur when a large load is started up unexpectedly, or when power is shorted to ground or another line.  Even loose cable connections can be the culprit.

To understand how low-voltage effects electric motors, one must understand the applied voltage to motor torque ratio.  Torque changes as the square to the voltage applied.  So a 10% increase in voltage will result in a 21% increase in torque.  Conversely, a reduction to 90% of the rated voltage will result in a 19% reduction in torque.  A more severe undervoltage condition - say 20% below the rated value, will reduce the motor's torque to 64% of its rating, resulting in 156% motor overload condition and catastrophic failure.

When does overload come into play in a low-voltage situation?  When the motor torque decreases below the torque required by the load, the motor will stall.  This is a bad situation if not caught immediately, as the motor now simply becomes a generator of heat.  Increased heat can damage the motors windings and insulation if the low-voltage event is long enough in duration.  This damage is permanent, and will result in a shorter life span or even a catastrophic failure.  In a prolonged low-voltage event, the only motor that is safe is one that is turned off.

Quick response techniques and computer monitoring and control equipment can reduce or even eliminate the damage of low-voltage events.  Thermal protectors or condition-monitoring devices can detect abnormally high winding temperatures and automatically shut down the motor. 

Being proactive is key in avoiding serious problems.  And thanks to computers, most everything can be monitored and controlled more accurately now.  This includes the electric motors that you rely and depend on.

Wednesday, October 8, 2014

ISPE Boston Chapter Product Show

Sharpe Mixers exhibited at the ISPE Boston Chapter Product show on October 1, 2014.

The International Society of Pharmaceutical Engineers encourages local chapters to produce these one-day exhibits.

They take place all around the country.  Sharpe Mixers participates in several of them, including Boston, Philadelphia and San Francisco.

This is one of the biggest chapter product shows in the country, attracted several hundred vendors to Gillette Stadium, home of the New England Patriots.

This year’s show was the biggest ever.  Attendees kept up a constant flow through the two clubhouse exhibit areas.

Quite a few of our customers in the New England area stopped by to say hello and see what’s new at Sharpe Mixers.

Many of our customers also exhibit at this show, including vessel fabricators, systems integrators, consulting engineers and contractors.

These table top shows offer a lot of bang for the buck.
 
Look into ISPE Chapter exhibits, as well as other engineering and production societies like ASME, Mid-West Food Processors and others for opportunities.


Submitted by
Fred DeCicco
North American Sales Manager