NO-FLOW SAFETY SWITCH
Compressor and Engine Cylinder Protection Against Lubrication
Failure
- Fail-Safe wear pattern.
No dangerous "shoulder" to prevent
shutdown so that switch is always functional with clean oil above its
pour point.
- Shutdown time adjustable over a wide range
- Explosion-proof models available
- Overpressure rupture assembly optional
- Switch contact rating - 2A at 30 VAC / DC
The Kenco No-Flow Switch mounts in the line between the lubricator
and cylinder. Oil flow is through the switch -- forcing the plunger off
its contact. Its rate of travel is controlled by fluid slippage past the
precision-fit plunger, preventing premature shutdown. If the lubricator
stops pumping, the plunger will drift to the contact and stop the
engine. On start up, the first stroke of the lubricator automatically
opens the switch. In operation the plunger can pump out of its hole on
very high feed rates and does not obstruct flow. The time interval
between lubrication failure and shutdown can be adjusted by increasing
or decreasing the compression on the spring.
The switch is available with an overpressure rupture assembly which
will instantaneously bleed off and stop the engine in the event the
lube-line check-valve plugs. The standard rupture disc fails at 1750
psi. Other rupture-pressure available on request.
The non-explosion proof switch has been tested to 5,000 psi. Its
maximum recommended working pressure is 2,000 psi. The explosion-proof
switch has been tested to 15,000 psi and its recommended working
pressure is 8,600 psi.
Equipment Specifications |
NFS-3: No-Flow Switch without mounting
bracket
NFS-4: No Flow Switch with mounting bracket for Ajax
NFS-5: Triple No-Flow Switch with mounting bracket for large
Ajax (3 switches on one bracket)
NFS-6: Explosion-Proof No-Flow Switch |
NFS-7: No-Flow Switch with overpressure rupture
assembly
NFS-9: No-Flow Switch with overpressure rupture assembly and
mounting bracket for Ajax
NFS-25: Explosion-Proof No-Flow Switch with overpressure
rupture assembly |
Parts List and Instructions
Description |
Part # |
Item # |
-3 |
-4 |
-5 |
-6 |
-7 |
-9 |
-25 |
Body |
B-19188 |
1 |
1 |
1 |
3 |
- |
- |
- |
- |
Body-Explosion Proof |
B-19190 |
1 |
- |
- |
- |
1 |
- |
- |
- |
Body-w/Rupture Disc Mtg. Hole |
B-19189 |
- |
- |
- |
- |
- |
1 |
1 |
- |
Body-Explosion Proof w/Rupture Disc Mtg. Hole |
B-19191 |
1 |
- |
- |
- |
- |
- |
- |
1 |
Pusher |
A-19185 |
2 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Spring |
A-794 |
3 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Piston |
B-19184 |
4 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Back-Up Ring |
P-19237 |
5 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
O-Ring |
P-13011-B |
6 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Adjustment Screw Housing |
B-19187 |
7 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
O-Ring |
P-13015-B |
8 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Set Screw |
P-19028 |
9 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Hex Nut |
P-1960 |
10 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Plunger |
A-19186 |
11 |
1 |
1 |
3 |
1 |
1 |
1 |
1 |
Contact Switch |
A-687 |
12 |
1 |
1 |
3 |
- |
1 |
1 |
- |
Contact Switch |
A-802 |
12 |
|
|
|
1 |
|
|
1 |
O-Ring |
P-13013-B |
15 |
|
|
|
1 |
|
|
1 |
Installation and Operating
Instructions
- Switch MUST be mounted either vertically (terminal end up) or at a
minimum angle of 20 º off horizontal with terminal end at the high
point. This prevents water from accumulating around switch contact
(see figure 2).
- A 25 micron sintered bronze or similar in-line type filter should
be installed ahead of the no flow switch. These are available from
either KENCO or most manufacturers of lubricators.
- To assure constant oil viscosity, mount switch in a warm place
near cylinder lube-line check valve or point of lubrication. The
"NFS-4", "NFS-5" and "NFS-9" no flow switches for Ajax are provided
with brackets for mounting to one of the screws which hold the cast
cover to the cylinder near the cylinder check. Connect no flow switch
contact wire to magneto or alarm/shutdown switch.
- Connect line from lubricator to inlet port on no flow switch.
- Hand pump lubricator until oil flows from outlet port; then
connect line from outlet to point of lubrication.
- Switch is factory adjusted for a shutdown time of approximately 3
minutes using SAE 30 oil at 100 º F. The switch is viscosity
sensitive, therefore, shutdown time will vary with oil viscosity. Many
compressor manufacturers indicate that 10-15 minutes operations after
cessation of lubricant flow is acceptable so it should not be
necessary to make seasonal adjustments.
- If adjustments are necessary, ensure that adjustments are made
while engine / compressor / no flow switch are at their normal
operating conditions. The adjustment setscrew is located on bottom of
switch housing. Turn setscrew IN to decrease shutdown time and OUT to
increase. Shutdown time can be determined by removing / disabling
lubricator pumping unit. On multiple pump installations pumping at the
same rate, the setting can usually be transferred from one switch to
another by making the distance from the end of the adjustment setscrew
to the end of the adjustment setscrew housing equal on all switches
(see figure 1).