Revision 1
9.
End
fittings
and
couplings - High pressure hose and end fittings and couplings shall
be manufactured to be compatible with the hose and tested as a unit.
10.
Jetting
gun
extension - This is a length or lengths
of
tube carrying high pressure fluid
to the nozzle. Each shall be manufactured from suitable material for the application.
End connections shall be suitable for the application. The extension is used in
conjunction with a control valve
(IIID#6 and IIID#7 above). The extension shall have
a minimum burst strength
of
at least two and a half (2.5) times the highest actual
operating pressure being used.
11.
Nozzle - The nozzle creates the water jet, or jets, at the required velocity, flow rate,
pressure, shape, and distribution for a particular application. Combinations
of
forward
and backward directed water jets are often used to balance the thrust.
Such nozzles
may be referred to as tips, jets or orifices.
12.
Water
jet
- A jet stream
of
water produced from the individual outlet orifice
of
a
nozzle. The shape
of
the jet
is
determined by the form
of
the orifice while the speed at
which it travels is determined by the orifice design, orifice area and flow. The pressure
drop at the orifice is a result of an increase in velocity. The most commonly used
jet
shapes are the straight-jet and fan-shaped jet.
a.
Straight
jet
- Concentrates the stream
of
water over a small area
of
the workpiece by
minimizing the spread. A typical application is for cutting or for general cleaning
of
matter with higher shear and/or bond strength.
b.
Fan
jet
- Spreads the stream
of
water in one (1) plane, so giving a wide band coverage
of
the work piece. A typical application is for cleaning larger areas requiring less
energy to remove unwanted matter.
13.
Jetting
hand
manifold
and
spray
bars
- These are pieces
of
equipment into which
individual nozzles are fitted.
14.
Foot control valve - The lance/gun operator's control valve (IIID#6 and IIID#7
above) may be arranged for actuation by the operator's foot if desired, either in place
of, or in addition to the hand-control.
An adequate guard should be fitted to prevent accidental operation and the base plate
area should be sufficient to ensure stability in use.
If
on the dump type (llID#7 above),
the layout should ensure that the dump line, if used, is restrained from whipping when
the valve is released.
15.
Jetting
gun - A portable combination
of
operator's control valve (IIID#6 and IIID#7
above) and nozzle (#11 above) which resembles a gun in layout and outline.
The control valve is hand-operated, generally by a squeeze action
of
the hand
of
the
operator, who should always have control
of
this device and may be
of
the dry shut off
(IIID#6 above) or dump (IIID#7 above) type, the gun being named accordingly. The
hand-control normally takes the form
of
a trigger or lever which should be provided
with either a guard adequate to prevent accidental operation, or the means
of
being
© Copyright January,
2001
NLB Corporation
2-16
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