Hoffman Media EDD-4C manual Search Feature, Overflow/vent hose

Abuilt-in, SCADA-compatible report-back mechanism provides the status and alarm information. This information is sent to the local PLC on site. The following signals are reported:

•OK state – signals that the oil drip rate exceeds a factory-set threshold. Whenever the oil drip rate falls below this threshold, the OK state is disabled and a relay contact can turn off the well pump directly or signal the SCADA room, which in turn can shut down the pump.

•Drip rate count– transmits the oil drip rate to the SCADA room, thereby providing the data to calculate oil consumption.

•Lack of oil alarm – the Dripmaster detects and warns of a lack of lubrication, as a result of an empty oil tank or blockage in the oil inlet or outlet.

Manual operation is possible using the OPEN and CLOSE push buttons on the control panel. The built-in peephole allows the operator to count the drips per minute.

Switching between the Pre-lube (pump off) mode and Normal (pump on) mode is accomplished by applying or removing a 24 V AC/DC voltage to the S.B. terminals in the connection box. Applying a 24 V AC/DC voltage sets the Dripmaster to the Pre-lube mode of operation. Removing the 24 V AC/DC voltage causes the Dripmaster to switch to the Normal (pump on) mode.

Search Feature

In exceptional cases, where only a few drops are counted, or none at all, the drip search function is activated. This situation occurs if there is needle valve blockage or when there is a continuous flow of oil. In the continuous flow case, there are no individual drops and consequently no counter readings. Continuous oil flow may occur when filling an almost empty oil tank, for example. In case of partial blockage, the drip search function scans until drops appear (the needle valve opens continuously until drops are detected). If no drops are detected during the drip search (if the oil blockage or continuous oil flow persists), then the needle valve eventually reaches its upper limit, the UL LED illuminates briefly, and the motor changes its direction of rotation and starts to close the needle valve (Figure 10).

Control circuitry interface

Servo motor

Overflow/vent hose

Oil inlet

Manual oil flow switch

Internal solenoid

Needle valve assembly

Lower Limit switch

Upper Limit switch

Photoelectric sensor

Oil outlet

Drip verification peephole

Figure 10: Dripmaster EDD-4C Needle Valve Assembly

When and if oil drops are detected, the search function stops, and normal stabilization resumes. If no drops are detected while the needle valve is closing, then the needle valve eventually reaches its

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