DeviceNet-compatible solenoid valves can reduce
wiring costs
Lawrence G. Ryba, Marketing Manager
Scrader Bellows Pneumatics, Cuyahoga Falls, OH
Point-to-point wiring costs for outputs and inputs to devices like solenoid valves, limit switches, proximity switches, motor starters, or PLCs may range from $50 to $400. To reduce these costs, pneumatic valve manifolds can be provided with the DeviceNet serial communications protocol. An open-architecture communications network, DeviceNet is supported by the Open DeviceNet Vendors Association (ODVA).
Manufacturers who belong to this association develop products that comply with the established hardware and/or software specifications to allow "plug-and-play" communications. Using a DeviceNet system can reduce wiring installation costs as much as 80% and total installation costs by 50%. The technology features a sophisticated broadcast communications protocol to "arbitrate" messages on the network.
A pneumatic valve manifold can support as many as 32 outputs and 32 inputs. Several of the manifold valve series feature a plug-together pc board that eliminates the need for hard wiring between valve stations and the DeviceNet communications module. To further reduce installation costs, modular bolt-on I/O sections are available. Each module allows a maximum of 16 points of external I/O via 12-mm "Euro" connectors. The standard driver configuration will support 3W/24V dc solenoids--or solenoids rated to 11W with an optional high-wattage driver card.
To speak with a Schrader Bellows applications engineer call: (216) 922-1306.
Installing mounted bearing units for tough jobs
Patrick Carey, Applications Engineer SKF USA, Inc., King of Prussia, PA
Conventional roller bearing units, when exposed to dirt, moisture, and other contaminants, are susceptible to seizure on the shaft. The eccentric fit between the shaft and the bearing bore leaves a gap that allows contaminants to enter, causing corrosion. As a result, the shaft and bearing are often irreparably damaged during removal.
However, original equipment designers have an alternative to standard unit roller pillow blocks--SKF's Pop Releasespherical roller bearing unit. Unlike conventional units--held in place with set screws or locking collars--Pop Release employs a patented, multi-stepped sleeve arrangement.
During mounting, the bearing slides easily onto the shaft when the bearing's inner ring is displaced up a series of inclined planes, compressing the sleeve to a nearly 360-degree concentric fit with the shaft. This secures the unit to the shaft and minimizes the risk of corrosion, increasing the bearing unit's service life.
A mechanic using only an Allen wrench can safely remove the bearing unit in minutes without damaging the shaft. Furthermore, Pop Release can be used with commercial-grade shaft tolerances.
Pop Release utilizes a high-capacity self-aligning spherical roller bearing that tolerates as much as λ ½ degrees of shaft misalignment. The bearing unit has been successfully applied in conveyors, mining equipment, commercial washing machines, and fans.
To speak with an SKF applications engineer, call the SKF technical hotline at: (610) 962-4800.
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