the piston rod, when maximum wear of the piston wear band occurs.
2.3.6.8
Cylinder and cylinder Heads
a.
Cylinders and cylinder heads shall be cast iron with integral
cooling water passages. Air-cooled cylinders shall not be
permitted. Cylinders shall be spaced and arranged to permit
access to all openings and components, including water jacket
opening covers, distance piece covers, packing, valves, unloaders,
or other controls mounted on the cylinder, without removing the
cylinders, the cylinder head, or major piping. Water jackets
shall be arranged so that there are no gasketed joints which might
allow water to enter the cylinder.
b.
Cylinder liners or provisions for reboring: Replaceable hardened
stainless steel cylinder liners shall be provided or the cylinder
walls shall be of thickness to permit reboring to a radial depth
of at least 1.60 mm 1/16 inch without encroaching on the maximum
allowable working pressure or the maximum allowable rod load.
Cylinder walls or liners using fluorocarbon rings and wear bands
shall be honed to a finish of 0.25 to 0.51 micrometers 10 to 20
microinches and fluorocarbon burnished.
c.
Fasteners: Cylinder heads, stuffing boxes for packing, clearance
pockets, and valve covers shall be secured with studs. Cylinder
lips supporting these devices shall be fabricated so that
overtorquing studs or nuts will not cause lip failure. Studs
shall be ASTM A 307, Grade B, and shall have each end chamfered to
remove the first one-and-a-half threads. Studs shall be secured
into tapped holes by interference fit or other approved means.
d.
Cylinder coolant system: Cylinder and cylinder head coolant
systems shall be designed for not less than [_____] [517 kPa
(gage)] [175 psig] working pressure and for a [_____] [69 kPa
(gage)] [10 psig] maximum pressure drop. Recommended flow rates
shall be based on no more than a 6 degrees C 10 degree F
temperature rise and a 0.002 fouling factor on the coolant side.
Provisions shall be made for complete drainage of coolant.
2.3.6.9
Valves
a.
Valves shall be alloy steel selected for long life, and shall be
ring, plate, or leaf form, direct or pilot pressure actuated.
Suction valves shall be provided with unloading devices for
capacity control regulation. Each individual unloading device
shall be provided with a visual indication of its position and its
load (loaded or unloaded) condition.
b.
The valve design (including that for double-decked valves) shall
be such that valve assemblies cannot be inadvertently reversed,
nor a suction valve assembly be fitted into a discharge port.
c.
Valve seats shall be removable. Valve seat-to-cylinder gaskets
and valve cover-to-cylinder gaskets shall be solid metal.
Nonmetallic gaskets shall not be used.
d.
The valve and cylinder designs shall be such that the valve cage
or the assembly bolting (or both ) cannot fall into the cylinder
even if the valve assembly bolting breaks or unfastens.
SECTION 15214N
Page 20
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