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Pneumatic/Electric
Lube Sentry Valve
PNEUMATIC LUBE SENTRY VALVE
OPERATION: Initiate lubricant flow from the lube pump serving the
divider valve or pump to point system (until flow has been established,
the electric or pneumatic circuit to the Lube Sentry must be bypassed).
Lubricant passing through the hydraulic section of the valve (See Figure
1 or 2) from port (1) to port (2) moves to piston (3) in the direction of the
arrow. The actuator rod (4) is attached to piston (3) and simultaneously
moves in the same direction allowing the directional spool (5) in the air
valve of the Pneumatic Lube Sentry (See Figure 1) to permit air to flow
between port “A” and port “C” or tripping the microswitch(es). (See Figure
2 Note 2 on the Electric Lube Sentry.) The Lube Sentry is now in a flow
position.
When lubricant flow stops, spring (6) returns piston (3) in the opposite
direction, closing the porting to the lube outlet (7). The lubricant ahead
of piston (3) is forced back through the adjustable needle valve (8) at a
controlled rate. As piston (3) returns to the right, the attached actuator rod
(4) moves the Pneumatic Lube Sentry directional spool (5) permitting air
to now flow between port “A” and port “B” (See Figure 1), or changing the
position of the microswitch(es) (See Figure 2 Note 2) on the Electric Lube
Sentry. The Lube Sentry is now in a no-flow condition. Figure 1 shows a
typical no-flow position.
Adjusting needle valve (8) clockwise increases shutdown time. A
counterclockwise adjustment decreases the shutdown time.
Note 1: Pneumatic Valve Operation (During Lubricant Flow)
ELECTRIC LUBE SENTRY VALVE
Flow - Green Light - ON; Red Light - OFF
No-Flow - Red Light - ON; Green Light - OFF
Operation Port “A” Port “B” Port “C”
Norm. Open Air In Plugged Air Out
Norm. Closed Air Out Air In Plugged
Figure 1. Pneumatic Lube Sentry Valve Figure 2. Electric Lube Sentry Valve
Note 2:
FLOW CONDITION :
For Closed Contact: Use Red and Blue Wires (Red Common)
For Open Contact: Use Red and White Wires (Red Common)
NO-FLOW CONDITION:
For Open Contact: Use Red and Blue Wires (Red Common)
For Closed Contact: Use Red and White Wires (Red Common)
CAUTION: If only two of the three wires are used, tape un-used wire.
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Manzel® Pneumatic/Electric Lube Sentry Valve
INSTALLATION
General Lube Line Connection
The Lube Sentry Valve should be located in the lube line 1.
downstream of pump, filters, and controls, but ahead of the
master divider valve. (A high-pressure line filter placed after
the pump is insurance against system plugging due to oil-born
dirt.)
A pressure rupture assembly (Disk Relief Type) must be located 2.
in the main lube line between the pump and the line filter.
Always install Lube Sentry with “LUBE OUT” port up, to permit 3.
natural air purging of the device.
General Shutdown Reaction Adjustment
See graphs for minimum flow rates, with various viscosity oils, 1.
and shutdown time recommendations.
Start with the adjustment screw (Figures 1 & 2, Item 8) 2.
flush with end of housing. Turn on lube system with pump
discharging oil at normal flow rate and pressure.
45425
NOTE: Do not use below minimum recommended
flow rates or inconsistent shutdown times occur.
Graph 1. Minimum Flow Rate
Slowly rotate adjustment screw clockwise until the electric 3.
switch/air valve changes mode (flow condition).
Stop oil flow and note time for electric switch air valve to 4.
change mode (no-flow condition).
Start normal flow of oil and note that the electric switch/air 5.
valve changes mode (flow condition) within two minutes and
remains in this mode as long as normal oil flow continues.
For positive shutdown indication on the Electric Lube Sentry, 6.
an ohmmeter or continuity meter should be connected to
wiring as follows: No flow condition – continuity between red
and white wires. Flow condition – continuity between red and
blue wires. Caution – In an explosive atmosphere, use only
approved device for checking continuity
This is the minimum shutdown time attainable for the 7.
application. The shutdown time can be increased by continuing
to turn the adjustment screw clockwise. Caution – Do not
adjust shutdown time greater than shown on graphs or
inconsistent shutdown time will result.
Pneumatic Lube Sentry Valve Installation
Pneumatic Connections
Series Type (in-line) Safety Control Pneumatic CircuitsA. (See
Figure 3)
Trace pneumatic safety circuits from the source of its take-off 1.
air supply through the various safety devices used on the
engine and compressor to the entrance of the pilot air port
(bonnet port) on the safety control valve or gas shut-off valve.
Select the most convenient location to break into the air circuit, 2.
either between two other safety devices or between the last
safety device and the bonnet port of the safety control valve.
NOTE: At minimum flow rate, the shutdown time is not
adjustable. Times indicated are approximate results when
the attached procedure is followed. Attempting to increase
the shutdown time will result in inconsistent shutdown time.
Graph 2. Minimum Shutdown Time
Break the air circuit at the selected point and tube the Lube 3.
Sentry Valve into the circuit with air flow entering port “A” and
leaving port “C” (See Figure 1). If gas is used as the control
medium rather than air, tube the exhaust port “B” into a
suitable vent line.
CAUTION – Never plug port in series type shutdown circuits.
To test device for operation, start engine to initiate flow in the 4.
divider valve system. Operation of the air valve within the Lube
Sentry will be observed as the tripping out of the reset latch
(manual override) lever on the safety control valve (see Figure
3), and the continued operation of the engine.
After a short interval of running during which the engine and
compressor receive sufficient lubrication and all other safety
devices move to the RUN position, dump the output of the
pumps serving the divider valve systems by removing the
pump blowout disc or a pipe plug from the pump manifold
assembly. When the flow to the distribution system stops,
the Lube Sentry should operate to dump the pressure in the
pneumatic safety circuit, dropping out the safety control valve
to stop the engine. (If shutdown action is sluggish, reduce the
setting of the adjustable orifice through which air for the safety
circuit passes.
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