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| The latest information on hydraulic and
pneumatic motion control.
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September 21, 2009
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Check out some hot
industries
Two of our featured articles this week highlight technologies used
in two industries heavily dominated by fluid power — construction and
utility and lumber processing. Read on for those, as well as a web
exclusive article on sealing, and a tutorial on load sensing.
Watch out for your next issue of Fluid Power Monthly, as we'll be
highlighting a special webcast on hydraulic hose. Stay tuned for more
news next month!
- Mary C. Gannon
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A step beyond load sensing
Designers of mobile equipment must deal with many actuators
requiring hydraulic power. Machines may have a dozen hydraulically
powered functions, with three or more operating simultaneously. And
often, due to space, weight, or cost reasons, a common pump supplies all
the circuits.Thus, as an operator uses various circuits, control valves
must compensate for flow changes and disturbances. The goal is to ensure
adequate flow to all actuators, even when operating several systems
simultaneously, to avoid reducing machine performance.
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Keep hose on the straight and
narrow
Ditch Witch directional boring machines, made by Charles Machine
Works Inc., Perry, Okla., range from the compact JT520 that can pull
2-in. diameter conduit up to 150 ft, to the JT100 Mach 1, which develops
80,000 lb of tension for pipe lengths to 2000 ft. Ten models offer a
range of capabilities for trenchless underground installation of all
types and sizes of conduit, pipe, and other service lines.
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Web Exclusive — Multi-element sealing system
improves performance in high-load hydraulic applications
In hydraulic cylinders — used in everything from precise
positioning equipment in machine tools to heavy earth moving machinery
in the toughest working environments — the requirements for sealing
are varied and difficult. The applications are dynamic, often operating
at high speeds and significant pressures. A single seal is rarely a good
enough solution and in most cases, a sealing system as a configuration
of seals is required. For example, some solutions include U-cups with
back pumping ability in combination with a double-acting scraper or
step-seals in single or tandem configuration also in combination with a
double-acting scraper.
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Saw smarts come from control
Forest products manufacturers must generate profits from whatever
logs are available — even if they are of lower quality than in years
past. Therefore, mill operators look for machinery that automates the
process of optimizing log yields, and the manufacturers of the machines
are looking to make them smarter and more flexible than ever before.
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Diaphragm pressure regulator
An ultra-miniature, single-stage diaphragm pressure regulator from
Beswick Engineering provides greater flow than PRD series regulators.
PRDHF high-flow regulator is offered in a 10-32 ported version and the
PRDHF8 manifold mount version. PRDHF weighs 35 g in brass and stainless
steel and about 18.2 g in aluminum. Non-relieving design controls output
pressures from 0 to 30 psig and is especially suited to low pressure
regulation such as ½ psig. Maximum inlet supply pressure is 500 psig.
Both the inlet and outlet ports are tapped 10-32 UNF. PRDH8 has similar
features except it weighs 52 g in brass and stainless steel, and inlet
is a 5/16-24 UNF external thread and outlet port is through a 0.094-in.
diameter hole at the base of the regulator body. This design eliminates
the need for fitting and tubing connections.
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Electronic switches
The One series of digital pressure and temperature switches from
United Electric Controls offers fast response to changes, initiating
immediate and critical safety shutdowns in plant safety applications.
They offer fast response rates — 50 ms vs. 350 ms for a smart
transmitter. They come complete with on-board diagnostics, and are
suitable for alarm and shutdown applications that demand a switch that
never needs calibration, has programmable adjustability, and 0.1 percent
repeatability. They can be seamlessly integrated into a safety
instrumented system (SIS) that requires instruments with
self-diagnostics and is suitable for SIL1 applications right out of the
box.
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Hydraulic valves
The 100 and 150 series hard seat and soft tip mini valves from
Noshok are available in electroless nickel plated steel,
electropolished stainless steel, and natural brass, and come with a
Viton O-ring seal and a Teflon back-up ring below the stem threads to
protect them from corrosion and galling. Body-to-bonnet, metal-to-metal
seal below the bonnet threads isolates them from the process media. At
a maximum hard seat pressure rating of 10,000 psi for the stainless
steel and steel models and a 6000 psi rating for the brass models, the
100 series features a stem tip that is hard chrome-plated on
stainless-steel models to prevent galling, and stainless-steel stems on
steel models are standard. The 150 series features non-rotating soft tip
stem with back-up metal-to-metal seal and tip mini valve and a pressure
rating of 6000 psi for stainless steel and steel, and 3000 psi for
brass models.
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Exlar's patented actuator technology offers many times the
life of ball screw actuators and provides an efficient
electro-mechanical replacement for hydraulic or pneumatic cylinders.
These digitally controlled products
offer several advantages over other technologies.
www.exlar.com
SmartActuator series saves time, space, money
Tolomatic's SmartActuator is a controller, drive and motor integrated
into one compact and durable rod-style actuator. You get
cost-effective, 100% duty-cycle performance with fewer, cleaner
components.
See the video!
Pneumatic cylinders
Air cylinders are available in heavy-duty brass or stainless steel in
bore sizes to 3 in. They are corrosion resistant and operate for
millions of production cycles. Online configurator offers CAD models in
2D and 3D for easier ordering.
www.clippard.com/cylinders/
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Contact Information
Editorial questions: Mary Gannon
216-931-9498
Advertising/sponsorship opportunities: Virginia Goulding
216-931-9893
Machine Design
1300 E. 9th St.
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