Blagdon Pump X75 Aluminium - Manual (Page 8)

x75afvmdl7sm-rev0411 Page 6
AIR VALVE LUBRICATION
The pump’s pilot valve and main air valve assemblies are designed to operate
WITHOUT lubrication. This is the preferred mode of operation. There may be
instances of personal preference, or poor quality air supplies when lubrication of the
compressed air supply is required. The pump air system will operate with properly
lubricated compressed air supplies. Proper lubrication of the compressed air supply
would entail the use of an air line lubricator set to deliver one drop of 10 weight, non-
detergent oil for every 20 SCFM of air the pump consumed at its point of operation.
Consult the pump’s published Performance Curve to determine this.
It is important to remember to inspect the sleeve and spool set routinely. It should
move back and forth freely. This is most important when the air supply is lubricated.
If a lubricator is used, oil accumulation will, over time, collect any debris from the
compressed air. This can prevent the pump from operating properly.
Water in the compressed air supply can create problems such as icing or freezing
of the exhaust air causing the pump to cycle erratically, or stop operating. This can be
addressed by using a point of use air dryer (available from Warren Rupp) to supplement a
plant’s air drying equipment. This device will remove excess water from the compressed
air supply and alleviate the icing or freezing problem.
EXTERNALLY SERVICEABLE AIR DISTRIBUTION SYSTEM
Please refer to the exploded view drawing and parts list in the Service Manual
supplied with your pump. If you need replacement or additional copies, contact your
local Distributor, or the factory Literature Department at the number shown below. To
receive the correct manual, you must specify the MODEL information found on the
name plate of the pump.
MODELS WITH 1" SUCTION/DISCHARGE OR LARGER AND
METAL CENTER SECTIONS
The main air valve sleeve and spool set is located in the valve body mounted on the
pump with four hex head capscrews. The valve body assembly is removed from the
pump by removing these four hex head capscrews.
With the valve body assembly off the pump, access to the sleeve and spool set is
made by removing four hex head capscrews (each end) on the end caps of the valve
body assembly. With the end caps removed, slide the spool back and forth in the sleeve.
The spool is closely sized to the sleeve and must move freely to allow for proper pump
operation. An accumulation of oil, dirt or other contaminants from the pump’s air supply,
or from a failed diaphragm, may prevent the spool from moving freely. This can cause
the spool to stick in a position that prevents the pump from operating. If this is the case,
the sleeve and spool set should be removed from the valve body for cleaning and further
inspection.
Remove the spool from the sleeve. Using an arbor press or bench vise (with an
improvised mandrel), press the sleeve from the valve body. Take care not to damage
the sleeve. At this point, inspect the o-rings on the sleeve for nicks, tears or abrasions.
Damage of this sort could happen during assembly or servicing. A sheared or cut o-ring
can allow the pump’s compressed air supply to leak or bypass within the air valve
assembly, causing the pump to leak compressed air from the pump air exhaust or not
cycle properly. This is most noticeable at pump dead head or high discharge pressure
conditions. Replace any of these o-rings as required or set up a routine, preventive
maintenance schedule to do so on a regular basis. This practice should include cleaning
the spool and sleeve components with a safety solvent or equivalent, inspecting for signs
of wear or damage, and replacing worn components.
To re-install the sleeve and spool set, lightly lubricate the o-rings on the sleeve with
an o-ring assembly lubricant or lightweight oil (such as 10 wt. air line lubricant). Press
the set into the valve body easily, without shearing the o-rings. Re-install one end cap,
gasket and bumper on the valve body. Using the arbor press or bench vise that was used
in disassembly, press the sleeve back into the valve body. You may have to clean the
surfaces of the valve body where the end caps mount. Material may remain from the old
gasket. Old material not cleaned from this area may cause air leakage after reassembly.
Take care that the bumper stays in place allowing the sleeve to press in all the way.
Reinstall the spool, the opposite end cap, gasket and bumper on the valve body. After
inspecting and cleaning the gasket surfaces on the valve body and intermediate, reinstall
the valve body on the pump using new gaskets. Tighten the four hex head capscrews
evenly and in an alternating cross pattern.