Method of making an efficiency enhanced fluid pump or compressor
Reference Number: N 01-02
Inventors: Rao, V. Durga Nageswar; Fucinari, Carlo Alberto
Owner: NISTAC
USPTO Link:5638600
Invention Summary
It is an object of this invention to provide a fluid pumping apparatus that has relatively-moving
internal parts constituted of a light weight material, such as aluminum or magnesium,
to promote less mass particularly for automotive vehicle applications, while at the
same time enhancing pumping efficiency with essentially zero fluid leakage.
In a first aspect, the invention is a high efficiency fluid pump for compressing
gases or pumping liquids, the apparatus comprising (a) means for effecting a pumping
action by use of relatively movable parts which cyclically move together and move
apart at a zone to transfer fluid, the parts being constituted of a light weight material
selected from the group consisting of aluminum, magnesium, titanium, copper, bronze,
ceramics, such as silicon nitride, cordierire (magnesium aluminum silicate), (b) a
coating on at least one of the parts in sufficient thickness to provide essentially
zero clearance when said parts have moved together at said zone, the coating comprising
solid lubricants in a polymer resin matrix stable up to 700.degree. F. In case of
ceramic parts, a thicker coating is applied on a rough machined or as-molded surface
and finished by a standard grinding operation. This facilitates very rapid sizing
at a substantial savings in process cost, relative to uncoated ceramic parts.
The invention, in another aspect, is a method of making a high efficiency fluid pumping
apparatus for gas compressors or liquid transfer, comprising: (a) forming aluminum
based relatively movable parts that entrain and effect a pumping action of a fluid,
the parts having surfaces that cyclically merge together and move apart to transfer
fluid by placing a shear load on such surfaces; (b) machining said surfaces to a finish
of 100-150 microns per inch; (c) preparing said rough-machined surfaces by etching
or phosphating to effect a dimpled texture; (d) depositing a thin coating on the prepared
surface by spraying or rolling, the coating consisting of a mixture of solid lubricant
particles and heat curable resin that attracts gas or liquid molecules and is stable
up to a temperature of 700.degree. F., the solid lubricant particles having an average
particle size within the range of 0.5 to 10 microns, the coating being deposited in
a thickness to create a slight interference at said zones; (e) slowly heating the
deposited coating to a temperature of about 200.degree. F. and holding said temperature
for at least fifteen minutes followed by additional 15 minutes at 375.degree.-400.degree.
F.; and (f) after returning the temperature of the coating to room temperature, operating
said pump to abrade said coated surfaces to essentially a zero clearance between said
relatively moving parts.
An advantage of this invention is an enhancement of pumping efficiency by 5-11% and
an increase in pumped volume (density and pressure).