Features of the Type F-5 Midco Sand
Pump
The F-5 Sand Pump is a "line travel" type. The
wire line passes through F-2 head and is babbitted into the
plunger. As the line is allowed to reel off, and the sand
pump is resting on bottom; the plunger assembly travels down
through fluid until it rests on the shoulder formed by the
chiseler flat bottom. As line is reeled in, the automatic
valve in the assembly is closed immediately and all fluid
above the sleeve is trapped and forced through perforations
in the top of the tube. During the upward stroke, the inrush
of fluid through the Sand Pump bottom carries sand, shale,
etc. into the load chamber.
The velocity of the fluid moving into the load chamber is
controlled to a large extent by the speed at which the plunger
assembly is raised. The tube weight, in addition to weight
of other parts which composes the load chamber assembly, will
force the Sand Pump bottom to maintain contact with debris
in the well, assuring maximum operating efficiency.
The limited independence of movement which the F-7 plunger
has in relation to the F-8 sleeve, assures a sharp blow being
struck to the sleeve each time the plunger moves downward
during loading operation. Even in instances where the sand
pump doesn’t remain in an upright position while resting on
the bottom, this jarring effect practically makes certain
of a full stroke of the plunger.
The plunger, suspended below the sleeve and approximately
three feet in length, prevents sand or other debris, trapped
in the tube by any previous stroke, from interfering with
free upward movement of the sleeve. This, in addition to other
exclusive features of the Midco Sand Pump, eliminates "sanding
up" of the plunger assembly.
The method by which sleeve and plunger are connected does
not restrict in any way the freedom of the plunger to swivel
when the line is slackened. This tends to increase the life
of wire line by preventing kinks and excessive wear.
Standard sizes are 3", 3½" and 4".
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