switches to protect against shock and provide more stable instrument
operation. Snubbers shall be of stainless steel construction.
2.1.12.10
**************************************************************************
NOTE: For hydraulic cylinders with attached flexible
hoses, a counterbalance valve should be installed
directly on the cylinder so that the lower hose is
not objected to a static load.
**************************************************************************
A counterbalance valve shall be installed in the oil line to the bottom
side of the hoist piston as indicated to balance the load being held by the
cylinder. The valve shall be directly operated, have an external type
drain, and shall be adjustable for operating over a pressure range of
[_____] to [_____] kPa. psi. The valve shall be designed for a system
operating pressure of [_____] kPa. psi. The capacity rating for the valve
shall not be less than [_____] L/s. gpm. The valve shall permit
unrestrained flow to the underside of the hoist piston and shall function
to retain pressure in the hoist cylinder in the amount of the valve's
pressure adjustment.
2.1.13
Piping
Piping, tubing, and hose shall be designed for a working pressure of [_____]
kPa,psi, [Pipe shall be used when a 25 mm 1 inch or larger diameter is
required. Tubing shall be used when less than 25 mm 1 inch diameter is
required.] [External cylinder piping shall be as shown.] Pipe shall be
welded or threaded as required on the drawings.
2.1.13.1
Pipe
Pipe shall be seamless [steel conforming to ASTM A 106/A 106M, Grade B]
[stainless steel conforming to ASME B36.19M and ASTM A 312/A 312M, Grade
TP304]. The piping weight class shall be Schedule [_____].
2.1.13.2
Pipe Fittings
Pipe fittings shall be the socket welding type conforming to ASME B16.11
and made of [steel conforming to ASTM A 234/A 234M, Grade WPB] [stainless
steel conforming to and ASTM A 182/A 182M, Grade F304]. The pressure class
shall be [_____] kg. pounds. Flanges shall conform to ASTM A 182/A 182M
with the grade suitable for the pipe to which attached. Threaded fittings
shall also conform to the above, but shall be used only where absolutely
necessary for the application.
2.1.13.3
Unions
Unions shall be the O-ring type, made of stainless steel with
socket-welding ends. The Contractor may at his option substitute four bolt
split flanges with [Buna N] [Viton] O-rings for the unions.
2.1.13.4
Hydraulic Tubing
Tubing shall be seamless stainless steel tubing conforming to ASTM A 789/A
789M. The wall thickness shall be selected to provide a safety factor of 6
based on the manufacturer's ratings for burst strength.
SECTION 15010A
Page 25
Previous Page
