Design Guide On Hydraulic Cylinders
Design Guide On Hydraulic Cylinders
Design Guide On Hydraulic Cylinders
HYDRAULIC
CYLINDERS
Sponsored by:
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HYDRAULIC CYLINDERS DESIGN GUIDE
Cylinders are responsible for converting hydraulic power into linear motion to do work
or move a load by applying pressure to the cylinder’s piston. These somewhat simple
devices usually feature a basic construction, including a piston inside a cylindrical or
rectangular tube or body, end caps and housings, as well as necessary bolts, nuts, plugs,
bearings, rod seals and wipers, and more.
The two most common designs are welded-tube and tie-rod cylinders. Welded cylinders
are constructed of a heavy-duty tube that is closed off with a welded-on cap. Mounting
anchors, including trunnion, side lug and side tapped, clevis, bolt, and flange types,
are usually attached to the welded cap. A threaded gland on the rod end allows these
cylinder types to be easily repaired. The simpler, but less durable tie-rod cylinder is ▼
designed with bolts and tie rods that hold two castings on each end of the barrel MARY GANNON
together. Also easy-repairable, this cylinder design is common on NFPA or ISO cylinders. Editor
In this Design Guide, the editors of Fluid Power World provide tips on sizing, selecting,
mounting and maintaining these workhorses of fluid power.
TABLE OF CONTENTS
What are hydraulic cylinders? .................................................................... 2
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HYDRAULIC CYLINDERS DESIGN GUIDE
(continued)
What are hydraulic cylinders?
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5 TIPS FOR
CYLINDER
MAINTENANCE Careful inspection of cylinders
is necessary on a regular basis
to check for corrosion, pitting
and uneven wear.
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HYDRAULIC CYLINDERS DESIGN GUIDE
(continued)
5 tips for cylinder maintenance
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HOW DO Image courtesy
YOU SPECIFY
of Yates Cylinders
A HYDRAULIC
CYLINDER?
H
ydraulic cylinders are specified by the force required to After piston area is calculated, simply multiply its area by the
be pushed and moved, and they are specified by their available system pressure:
method of mounting. There are subordinate functions to
F=PxA
be considered when specifying a hydraulic cylinder, such fluid
F = Force in pounds
type, column strength and material construction. However, 90% of
P = Pressure in psi
cylinder applications are not exotic, and simply identifying force A = Area in square inches
and mounting requirements will suffice, leaving all else standard.
Let’s take an example to help with the math. We have a 4-in. bore
The first step in specifying a hydraulic cylinder is calculate the cylinder, and our system pressure is capable of 3000 psi:
required force. Factors required to determine force are the mass
of the load, direction of cylinder travel and angle of the force A = 3.14 x r²
vector. The mass is easiest to know, in most cases. The direction of A = 3.14 x 2²
A = 3.14 x 4
cylinder travel is also easy to determine; will the cylinder push or
A = 12.56 in²
pull on the load? It is important to consider the difference because
a cylinder pulls with less force than it pushes, due to the area F=PxA
taken up on the piston by the rod. The angle the cylinder pushes F = 3000 psi x 12.56 in²
on the load at affects the force required, but because this part of F = 37,680 pounds
the discussion requires trigonometry, I’ll leave it out for now. Let’s
just say that if you’re not pushing at ninety degrees to the load, it
requires more force.
A = πr²
A = Area in square inches
π ≈ 3.14
r = Piston radius (1/2 diameter)
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HOW DO HYDRAULIC
CYLINDERS FAIL—CONTAMINATION
T
oday’s fluid-power users, for the most part, are well aware Water is a common contaminant in petroleum-oil based systems
that keeping hydraulic fluid clean is essential in preventing that degrades fluid-performance properties and accelerates
premature failures and unexpected downtime. Nonetheless, oxidation and additive depletion. Exposing some seal materials
contamination remains a major cause of hydraulic-cylinder failure, to water—especially at elevated temperatures—also lowers their
particularly because it leads to seal failure and leaks. And it can physical properties. That translates to seals that lose strength,
come from several different and unexpected sources. harden, crack or even disintegrate.
Internal contamination is one obvious source. Particulate Polyurethane seals, for example, are subject hydrolysis effects
contaminants include dirt, wear particles from pumps and valves, in high-water-content fluids at temperatures above 50°C. That
and debris from internal breakdown of hoses. Contributing factors leads to loss of hardness and tensile strength, in turn allowing
include clogged filters and dirty assembly areas. fluid leakage past the rod seal.
Such contamination results in scored rods and cylinder-bore Users should ensure that seal materials are compatible with
surfaces and excessive seal wear. This causes leaks past the the fluid and system operating temperature. And experts
cylinder rod and head and into the environment. And it can recommend that users minimize water ingression through
increase internal leakage past the piston seals, which reduces suitable wipers and desiccant-style breathers. Finally,
efficiency. It can even exacerbate erosion problems, where maintenance technicians should routinely test for the presence
contaminants abrade the seal as media travels from the high- of water in the hydraulic fluid. Water-removal filters or
pressure to low-pressure side of the seal. dehydrators are recommended to control water content.
Damaged cylinder rods and bores can usually be repaired, Air is often overlooked as a fluid contaminant. Hydraulic fluid
but users should first determine the root cause or the problem always contains some dissolved air that causes no problems.
will soon return. Proper filtration keeps fluid clean and helps However, if air mixes with the hydraulic fluid and forms
prevent problems due to internal contamination. bubbles, that’s another story, as it can physically damage
the seals. Causes include air drawn past the rod seals; rapid
Also ensure proper flow through the cylinder. If the volume of oil decompression; high flow through an undersized port,
in a cylinder exceeds that of the hose between the cylinder and generating turbulence; and overrunning loads.
directional valve, it may not flow efficiently to the reservoir for
filtration. Instead, particulates remain in the cylinder and attack Air bubbles can lead to scoring, nibbling and other physical
the seals. Here, a fix is to mount the valve closer to the cylinder damage to the seal. Pressure shocks, particularly in cylinders
to ensure efficient circulation. Proper installation and alignment cycling at high speeds, can cause air bubbles to become
of the cylinder will also reduce the rate at which the cylinder itself heated, a condition often referred to as dieseling. The
generates fluid contaminants, by minimizing seal and bearing wear. combination of high temperature and high pressure can
ignite oil fumes inside the bubble and burn the seal face, and
External contaminants are another consideration. Hydraulic consequently lead to leaks and quick cylinder failure. Minimizing
cylinders are constantly exposed to external contaminants aeration of the fluid through proper design and operation, as
ranging from dust, mud and abrasive grit to metal chips and mentioned above, is a helpful option.
weld spatter. Fluid contaminants include coolants, washdown
water and rain. Dirt and fluid contaminants can be drawn into
a cylinder during rod retraction via a faulty wiper seal, so the
proper specification and installation of a rod wiper/scraper is Pleated bellows can
recommended. Likewise, a well-designed tank breather/filter protect finished rod
surfaces. They are often
keeps water and dirt out the system.
made of elastomer-
covered fabric, as well Installing boots or
Under particularly dirty conditions, consider installing boots as flexible vulcanized bellows like these from
or bellows over the moving rod. A pleated bellows/boot can and injection-molded Dynatect Manufacturing
protect finished rod surfaces from wear-causing elements, materials. Photo in particularly dirty
reduce downtime and lengthen cylinder life. These protective courtesy of Dynatect conditions can help
Manufacturing.
devices are often made of elastomer-covered fabric, as well as lengthen cylinder life .
flexible vulcanized and injection-molded materials. The covers
can be held in place by collars and hose clamps or flanges.
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HYDRAULIC
CYLINDER
MOUNTING
OPTIONS
H
ydraulic cylinders are available in a variety of styles
Image courtesy
and can be mounted in numerous ways. Here’s a of Yates Cylinders
look at some of the most common options and their
advantages and disadvantages.
Although some cylinders are manufactured with a generally For the remainder of this missive, I will refer to standard NFPA
poor build quality, such as with cast iron caps and heads, higher and ISO variants as simply tie-rod cylinders. The advantage to
quality cylinders are typically constructed with forged steel. The the standard tie-rod cylinder is in the modular nature of the parts
“welded” type cylinder is very common, and even though the used to create a finished product, such as the cap, barrel, head
specifications for their dimensions, sizes and rod treatments and rod sizes, which allow a cylinder to be assembled in a few
aren’t part of an industry standard, they are common enough in days from off-the-shelf parts.
construction that many manufacturers build them the same way.
Opposite to the rod side is the cap, which is essentially a block
The welded cylinder is simply a barrel with a cap welded to of forged steel machined with a deep ring to accept the barrel,
the bottom, and then with the mounting treatment welded to which seals with an O-Ring. The cap end is typically very simple,
that cap, typically a cross tube or dual tangs to mimic a clevis. with just a port machined to direct fluid into the piston side, the
The piston and rod are installed into the cylinder, and then a four drillings for the tie-rods and sometimes a cushion screw.
threaded head is slid over the rod and torqued onto the barrel. Opposite to the cap is the head, which is more complex and
Finally, the rod treatment is added to the cylinder, which is consisting of more parts. Besides the parts mirrored by the cap—
sometimes a cross-tube welded directly to the tip, or if the rod the port, the tie-rod and sometimes a cushion—the cap must
end was threaded, any other rod treatment common to the also contain the bushing, gland and the rod seal package.
industry, such as a clevis or a rod eye.
The standards for tie-rod cylinder design apply mostly to the
Cast tie-rod cylinders and welded cylinders make up a fair mounting dimensions, and less so for the internal design of
portion of the cylinder market, especially in the mobile the cylinder, which can vary significantly from manufacturer to
equipment industry, but the NFPA and ISO standards for tie- manufacturer. These differences can exist with piston design, head
rod cylinders are the most common in any high-end hydraulic design, rod gland and seal design etc., but the exterior mounting
machine. The metric ISO standard for cylinders is quite similar dimensions must remain the same, such as retracted length, clevis
to the National Fluid Power Association’s standard using pin diameter or trunnion dimensions, if so equipped.
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HYDRAULIC CYLINDERS DESIGN GUIDE
(continued)
Hydraulic Cylinder Mounting Options
A basic cylinder comes with no end treatments; however, by The lug mounting options use rectangular tabs machined from
simply drilling and tapping two threads each in the cap and the same block of steel as the head and cap, although they
head, we create the MS4 Side Flush Mount cylinder, just one are sometimes welded on. The four MS2 side lugs are on the
of many choices. Each mounting style has its advantages and bottoms of the head and cap, the MS3 center lugs are mid way
disadvantages, and although there are many options, the most up the head and cap, and the MS7 end lugs are mounted to the
popular choices are as follows: front bottom of the head and back bottom of the cap, reaching
fore and aft like sphinx paws. Because of the fixed mounting,
• MP1 – Fixed Clevis lug style cylinders are very rigid, although the nature of dual
• MP2 – Detachable Clevis (not pictured) mounting points can add worries of misalignment between the
• MF1 – Front Flange Mount front and rear lugs, especially related to bending or torquing of
• MF5 – Front Flange Extra Size Mount the mounting surface.
• ME5 – Front Head Flange Mount (not pictured)
• MF2 – Rear Flange Mount Finally, the MT1, MT2 and MT4 front, rear and intermediate
• MF6 – Rear Flange Extra Size Mount trunnion mounts, respectively, are an alternative to the clevis
• ME6 – Rear Head Flange Mount (not pictured) style pivot. They allow the rod to move through an arc as it
• MS2, MS3 and MS7 – Side Lug, Center Lug and End Lug extends and retracts, although they have a slight advantage in
Mounts, respectively column strength and precision of movement over a clevis mount,
• MT1, MT2 and MT4 – Front Trunnion, Rear Trunnion and especially the MT1 (front trunnion) and MT4 (intermediate
Trunnion Mounts, respectively< trunnion). The MT2 (rear trunnion) mount is slightly weaker,
especially if the rod isn’t rigidly guided. Trunnion cylinders
MP1 (fixed clevis) and MP2 (detachable clevis) are one of the experience smoother movement because the trunnion on either
most common types of mounting options used, especially in side of the cylinder is fixed to the machine with special mounting
applications where the cylinder must pivot through an arc as it brackets and bushings, and has less sloppy play in the joint
extends and retracts, such as with a boom crane or bin tipper. compared to a clevis.
The fixed clevis is a part of the cap itself—a detachable clevis
is bolted to the cap, and both allow engagement to a clevis
mounting bracket with a steel pin held in place with cotter
pins or snap rings. Clevis mounts require attention when being
applied, however, as they are highly prone to side load and
column strength issues, which I will discuss later.
MF1 (front flange mount), MF5 (front flange extra mount) and
ME5 (front head flange mount) are all methods of mounting the
cylinder off of, or part of, the head itself. MF1 has a rectangular
flange attached to the head, which protrudes from the sides of
the cylinder, and the MF5 has a larger square flange protruding
in all directions, which provides extra strength. The ME5, instead
of a flange being mounted to the head, uses an extra thick and
wide head, which itself attaches directly to the machine. These
options require the cylinder to be stationary and this fixed
centerline mounting provides them with high column strength.
The MF2, MF6 and ME6 rear flange mounts are similar to the
front flange family, except their respective locations are off the
cap rather than the head. The MF2 has a rectangular flange
attached to the head, but protrudes only on the sides, the MF6
uses the same larger flange as the MF5 and the ME6 has a
beefy cap containing mounting holes for direct attachment to
the machine. Being fixed centerline type mounts, they offer the
same strength advantage of the front flange versions.
Image courtesy of Yates Cylinders
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HYDRAULIC CYLINDERS DESIGN GUIDE
(continued)
Hydraulic Cylinder Mounting Options
All cylinders require consideration for stable Image courtesy of Yates Cylinders
and reliable operation, especially as it relates
to the rod as it extends towards the end
of cylinder stroke. If you’re like me, you’ve
wasted time discovering how many feet you
can get a measuring tape to extend out
into free air before it bends, dropping with
a boing-clank sound. This analogy loosely
translates into one of the issues experienced
by hydraulic cylinders. The longer the cylinder
stroke and the farther the cylinder extends
along its stroke, the higher the potential for
two common cylinder problems: side loading,
and column bending.
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WHAT IS THE DIFFERENCE BETWEEN
TIE-ROD AND WELDED CYLINDERS?
A
lthough both types of cylinders are used
in fluid power systems, the end caps used
to hold the cylinder together make the
difference. Welded cylinders are designed
with each end cap welded to the barrel. Mounts and
other fittings will also be welded to a cap. Static
seals are used to seal the head or gland of a welded
cylinder. These designs are permanent.
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When should
you use T
elescopic cylinders are a unique type of actuator able
to extend far longer than a traditional rod-style cylinder.
telescopic
Telescopic cylinders are manufactured using two or
more nested tubes inside one another, and these tubes
act as both the rod and barrel. Telescopic cylinders have as
many as seven stages or more, providing a compact footprint
cylinders?
with a surprisingly long stroke length. A cylinder with 120 in. of
stroke only needs 50 in. of retracted space, while a traditional
cylinder will always be longer than whatever its stroke length is.
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HOW DO YOU SAFELY DESIGN
AND USE HYDRAULIC CYLINDERS?
M
any of the failures in a hydraulic system show typically uses ag-type cylinders that feature cast end covers
similar symptoms: a gradual or sudden loss of high bolted together with all thread and nuts onto a honed tube. They
pressure, resulting in the loss of power or speed in also typically use O-rings for seals. These cylinders generally
the cylinders. In fact, the cylinder may stall under operate around 1,500 to 2,000 psi and are designed to be either
a light load or may not move at all. Often the loss of power quickly resealed or thrown away. Using this type of cylinder in a
is accompanied by an increase in pump noise, especially as construction application would prove to be dangerous and self-
the system tries to build up pressure. Any major component, defeating as it would be short lived for the work to be done and
including the pump, the relief valve, directional control valve, or may not hold up under the load requirements.
the cylinder, could be at fault.
3. Tie-rod or welded? When is it appropriate to use a tie-
In a sophisticated system, other components could be to blame, rod cylinder or a welded cylinder? The typical response is
but this could require the service of an experienced technician. By that manufacturers of stationary equipment generally rely on
following an organized step-by-step testing procedure in an orderly tie-rod cylinders, as they can be configured to fit most unique
fashion, the problem can be traced to a general area, and then if applications and have many applicable valving blocks, making
necessary, each component in that area can be tested or replaced. them simpler to configure to machinery. This reduces other
possibly needed valves to accomplish work desired and helps
In this article though, we want to discuss the safety tips
to reduce costs. Rated to NFPA standards, tie-rod cylinders
concerning cylinder design and use. What are some of the
are easily inter-changeable with other manufacturers. Welded
suggested things we should be looking for when selecting the
cylinders are most common in mobile equipment where weight
right cylinder for the job? Answering these questions before
and size of application work needs can be considered. These
installation is a start to safe and optimal cylinder design.
heavier duty designs are usually rated to 5,000 psi or higher.
1. Is the cylinder rated for the work to be done? Using the F = P Featuring a barrel that is bolted or welded directly onto the end
x A formula (Force = Pressure x Area) will ensure that the cylinder is caps, these designs do not require tie-rods, so thus are stronger
sized properly to do the work at the required system pressure. and more resilient in harsher environments.
2. Is the cylinder designed to handle the load? With so many Above all else, it is important to be sure to use a cylinder that
manufacturers today, choosing a cylinder that will hold up to the is rated for the job. Choosing a cylinder because of cost rather
load requirements is important. Be sure to evaluate the seals and than design can be a mistake in many ways. Seals, wear bands,
guide bands being used for bearing loads. Agricultural equipment shaft seals, and porting all play an important part of selection.
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The business end of hydraulics:
the cylinder
T
his article will talk about the business end of the hydraulic
system: The force produced by the cylinder. When using a
standard double-acting cylinder, there are three internal areas of
concern:
1. Piston area = transfer fluid pressure to force to extend piston rod
2. Net piston area minus piston rod area
3. Rod area = significant when cylinder is used in
regenerative action
For example:
• Extension force is 50 psi x 20 in.2 = 1,000 lb.
• Opposing force on rod side is 30 psi x 18 in.2 = 540 lb.
The net force the cylinder can exert against a load in the extension direction is:
1000 lb – 540 lb = 460 lb
Vertical gravity load—a non-friction load that requires full cylinder force to be
produced throughout the stroke. Additional force will be required and calculated in
to accelerate the load and to overcome loss due to supply flow and friction losses.
Stall-out load—in cylinders that are used on either vertical or horizontal presses,
when the press contacts the work piece the cylinder stalls. During cylinder piston
movement, they usually run in “free traverse” for most of the stoke. During free
traverse, very little pressure is required on the cylinder piston and the pump
supplies only the hydraulic circuit losses due to fluid flow friction. At stall, all fluid
flow friction disappears. When calculating pressures required at the cylinder port,
allow 5% for packing friction losses even with no movement through the packing.
Horizontal friction loads—horizontal cylinders can be used for either push or pull
applications.
• Push application is acceleration away from source.
• Pull application is acceleration towards source.
The force required for moving a load horizontal is less than the force required to lift
it. To calculate for a horizontal load, you have to calculate the load times the static
coefficient of static friction (resistance to movement created by molecular attraction
between load and surface materials)
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HYDRAULIC CYLINDERS DESIGN GUIDE
(continued)
The business end of hydraulics: the cylinder
Rolling loads—we all know how much a wheel makes it easier to move an object
across a surface. By replacing sliding resistance with rolling resistance, you require
a significant amount less force. With rolling load, there will be a breakaway force
required to set the load in motion; a force as little of 1⁄10 the load will break away
the load and then even less force is required to keep the load in motion. The
breakaway load is caused by the wheel as it applies a force on the surface material.
The displaced material from under the wheel is pushed out in front of the wheel.
As the wheel moves across the surface, it continually displaces the surface material
to the front of the wheel creating the rolling resistance. If you roll a wheeled chair
across the carpet, you can see the carpet bulge up in front of the wheel. Even
though we are rolling hardened steel across a steel surface, the steel will act just
like the carpet.
Shear strength for metal can be assumed to be about 75% of the metals rated
tensile strength and is expressed in psi. For accurate shear values, consult the
supplier of the material.
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HOW CAN YOU PREVENT
HYDRAULIC CYLINDER DRIFT?
▼
D
rift is the unintentional movement of a cylinder when it’s meant Because the fluid volume in the rod side of the cylinder is smaller
to be held in place by directional, PO check or counterbalance than the volume in the cap side of the cylinder, fluid has nowhere
valves. The objective of many cylinder applications is to move to go. You could literally remove the piston seals entirely, and the
a load to a predetermined position and maintain that position for cylinder will only drop a fraction of an inch as the pressure equalizes
various lengths of time. For example, a bucket lift used by utility inside the entire volume of the cylinder.
providers to work on power lines absolutely requires a cylinder to lift
to the desired position and stay there. Therefore, a drifting cylinder is
disconcerting at best and dangerous at worst.
Should any fluid leave or leak from the piston side volume, the
cylinder will lower (or drift) unintentionally. The cause of this drift
may be directly attributed to the path the fluid takes to exit. The
most likely culprit of cylinder drift is the valve located closest to the
cap side port. In most cases where the safe control of cylinders is
required, a counterbalance valve is that closest valve.
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HYDRAULIC CYLINDERS DESIGN GUIDE
(continued)
How can you prevent hydraulic cylinder drift?
PREVENTING DRIFT
So we know how cylinder drift may occur, so let’s discuss how to It goes without saying that a cylinder must be adequately
prevent or remedy drift. The first step to prevent cylinder drift maintained to ensure the sealing material is always fresh and ready
comes at the design stage. Going back to our first example with the to do its job. If you neglect maintenance duties, such as proper
counterbalance valve, you must understand how the valve interacts cooling and filtration, you can expect your seals to fail prematurely.
with the cylinder. Because a counterbalance valve is essentially a Even the most well-maintained machines will still see their cylinder
relief valve, there is always the chance it could crack open slightly if seals wear over time. To prevent leakage and drift from old, tired
load pressure is too close to the valve’s spring setting. seals, ensure you have in stock replacement seals to execute a quick
repair should cylinder drift become an issue.
A cylinder too small for the application may experience periods of
load-induced pressure exceeding the maximum value of the spring Lastly, preventing leakage that causes cylinder drift comes down to
inside the counterbalance valve. It’s unlikely the load will drop choosing and maintaining the correct valves, whether directional or
catastrophically, but the poppet or spool in the valve may begin to pressure. Although it’s not recommended to hold a load using only
crack open, allowing the cylinder to drift downward. Ensure that you a closed port directional control valve, cylinder drift may still occur in
choose your cylinder bore and counterbalance valve pressure range applications, as discussed previously. Select high-quality spool valves
far enough apart never to experience pressure overlap. which are machined with tighter clearances that are less likely to leak
across any of its ports. If you’re ever curious about the quality of your
Choosing the correct cylinder and seal package for your application directional valve, plumb a 5-gallon accumulator to a work port charged
is also essential. Well-engineered and well-manufactured cylinders to system pressure and then see how long it takes to pressure to
offer tighter clearances between their piston outside diameter and decay. The faster the pressure decays, the more leakage it allows.
the cylinder barrel inside diameter. This tighter gap helps seals
better prevent leakage not only when new but especially when If you rely on counterbalance valves to hold a load, you may want to
worn. As well, higher quality cylinders are offered with better quality select only poppet-based valves. Spool valves are inherently leaky, and
finishes, such as a chromed and honed finish to the barrel ID. any sustained pressure at their work ports will result in some leakage.
Most reputable valve manufacturers publish the leakage rate of their
The seal selection makes a difference because not all seal types valves, so compare valves to ensure you’re getting the lowest leakage
work as effectively at sealing, strangely enough. Some seals, such valve possible. However, due to their cone and seat design, poppet
as U-Cup or lip seals, offer low-friction designs better suited to valves offer the lowest leakage rate for directional or pressure valves.
high velocity or low friction applications requiring little or no static Always keep in mind that leakage in any form could result in drift.
friction. As a result, they’re designed to break away from a stop
position more quickly and will “chatter” less in most applications.
Under low pressure, a lip seal also has a better chance of leaking
since they count on pressure pushing the lips out against the wall
surface, thereby improving their sealing.
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WHAT ARE CYLINDER STOP TUBES?
C
ylinder stop tubes are simply metal collars or tubes that strokes unnecessarily lengthens the cylinder and increases weight.
are placed around a hydraulic or pneumatic cylinder’s rod They also reduce a cylinder’s usable stroke length.
between the piston and head. They are designed for use
only when a cylinder will have extra long strokes. Used primarily in Sizing a stop tube is simple: installing 1 in. of stop tube is recommended
horizontal applications, they help to prevent side loading and other for every 10 in. beyond 40 in. They are available in a variety of materials,
column strength issues such as jackknifing or cylinder buckling. Side including steel, brass and aluminum, among others.
loading happens when the rod is retracted and pushed out of its
Other things to keep in mind when designing a cylinder with a
normal travel route by a mass or force. This up, down or side bending
stop tube in mind include: the weight of the load and the type of
force can cause rapid wear of a cylinder or even worse, a bent rod.
movement it is (one or two directions, etc.); the cylinder’s cycle rate;
The stop tube provides side load support during those long the cylinder’s piston rod diameter; and finally, mounting style.
extensions of the rod. Their use removes the risk of a piston
bottoming out and prevents the cylinder from extending too far.
This, in turn, avoids piston bending. Additionally, cylinder stop tubes
decrease the risk of bearing surface overloads.
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