The use of a “Stop
Tube” placed in a low pressure hydraulic cylinder is an
effective means of reducing the side load imposed upon the
cylinder rod cartridge in long stroke horizontal applications. The
Stop Tube basically prevents the piston within the cylinder from
bottoming out against the head end cover, thereby, increasing the
support of the piston rod. Proper utilization of Stop Tubes will
significantly reduce rod cartridge failure in this type of long
stroke application. Generally speaking, one should consider the
use of incorporating the Stop Tube feature in cylinder stroke
lengths in excess of 36”, however, the cylinder mount and load
weight will be two of many other factors used in determining if a
Stop Tube is required for your application.
The cylinder mounting style
and other data applicable to the application at hand are
important factors to know in making the determination for the
correct length of the Stop Tube.
Please note that when a Stop Tube is used; the cylinder length
will grow, beyond the standard NFPA length, by the same extent
as the length of the Stop Tube.
The
Example below shows a Stop Tube Part Number Description.
(
NOTE - when entering a Stop Tube into our configurator, please
enter the ACTUAL
stroke required, then enter required stop tube/ spool length in
the top section )
Some additional issues to consider in making the determination for
the correct Stop Tube length are as follows, we recommend that you
discuss all of these and other relative issues with our
engineering staff if you are unfamiliar with the use of cylinder
Stop Tube applications:
Is this a horizontal or vertical application?
Is the piston rod guided or supported in any way?
What is the weight of the load being moved?
Is the load which is being moved assisted in any way, or is
the load unassisted and unsupported along the path of its
travel?
What is the cycle rate of the cylinder?
What is the diameter of the cylinder piston rod?
Is the load which is being moved present on both the
extended and retracted stroke of the cylinder or is it in
just one direction? If one direction, is it on the extended
stroke or the retracted stroke?
What is the cylinder mounting style?
Peninsular’s design for Stop Tube applications incorporates the
use of improved engineering features over many conventional Stop
Tube designs which are commonly found within industry today.
Illustration #2 below:
Shows the Conventional "Stop Tube” Design
Advantages for Peninsular's Stop Spool:
The improved Peninsular Stop
Spool design provides increased cylinder stability because
of the piston and rod assembly as compared to commonly
used conventional Stop Tube designs.
Stop spool design eliminates
internal cylinder damage and tube fracturing because of the
increased surface area of the piston impacting the inside
of the head end cover as opposed
to the thin edge of the Stop Tube which could fracture.
Stop
Spool can be cushioned on the head end.
An additional piston wear band is added
because of the addition of the second piston, thus,
extending cylinder life.
By selecting the Stop Tube feature a /N will become present in the
cylinder part number after you have submitted the cylinder for
configuration, and both the actual stroke and the overall total
stroke length will become present in the cylinder part number.