Lincoln SKF SMBM-V EEX, Руководство по эксплуатации

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The covering of this variable restrictor D
3
is the result of the
equilibrium of the pressures p
1
and p
2
and of the spring force F
on the control piston. The influence of viscosity is only slight,
due to the relatively short hydraulic length which arises from
the geometry of the plug-in nozzles
D
1
or D
1
/ D
2
, respectively.
The flow rate is thus determined only by the differential
pressure
p
1/2
, which is constant. This results in the flow rate
also being constant.
p1*A = p2*A + F (A = cross-sectional area of the control
piston)
Δp = p1/2 = p1 – p2 = F/A = const.
Δp = const.
Q = const. 1)
Prerequisites
To ensure impeccable functioning of the flow limiter, p
1
must
always be greater than the differential pressure p
1/2
plus the
back pressure downstream of the flow limiter. p
1
>
p
1/2
+
p
3
We recommend that a reserve of approximately 15% be
provided for the selection of the oil pump.
Q
pump
≥ 1.15 * ΣQ
in
Circulating-oil lubrication systems with flow limiters,
which are
equipped with downstream progressive metering devices are
usually run with a system pressure of 20-25 bar (290-360 psi),
while a system pressure of 16 bar (230 psi) is sufficient for
systems comprised solely of flow limiters.
Fig. 6
Functional diagram SMBM-X
Table 7
Legend to Fig. 6
Item Designation
1 Inlet volume flow Q
in
2 Outlet volumetric flow Q
out
3 Inlet pressure p
1
upstream of D
1
4 Control piston SK
5 Plug-in nozzle D
1
(nonadjustable restrictor)
7 Variable restrictor D
3
8 Inner pressure p
2
downstream of D
1
Table 7
Legend to Fig. 6
Item Designation
9 Spring force F
10 Stop screw AS
11 Signal transmitter SG (optional)
12 Outlet pressure p
3
downstream of D
2
(back
pressure in the system)
13 Gear-type flow indicator with pulse generator