Automatic Pump Control

With proper instrumentation, almost all pump stations can be operated automatically. Remote monitoring is simple, relatively inexpensive, and can provide safe operation and signaling of nearly all operating conditions. Equipment is presently available to measure, record, and transmit the operating conditions to remote locations. The proper equipment can thus relieve worry about the operation of the facility even if it is many miles from the operation's headquarters. Automatic control can be a simple float switch or a pressure switch, or it can be sufficiently complex to provide reliable operation under the most critical or adverse conditions. Automatic control can provide greater reliability, and its cost can depreciate over only a few years. Furthermore, the automatic recording of flow rate, flow totalizing, and periods of operation provides valuable data for analyzing the performance of the pumping installation as well as the possible cost savings in pumping during off-peak power periods.

Where the safety of a mine is dependent on the reliable operation of the dewatering pumps and controls, the following minimum requirements should be considered:

1. There should be a sump level alarm for high water, both local and remote (at the surface).

2. Sump level control should be dependable. For example, electrodes are generally unreliable in waters that leave a conducting film.

3. The control should be programmed where more than one pump is installed. However, the use of an alternator is not always desirable because all pumps are exposed to the same degree of wear. It is preferable to have one standby pump programmed through a sequence selection switch to operate at least once per week.

4. Pump priming should be positive. Hydraulic devices should be combined with electric controls so complete dependence is not on the electric control. The presence of water in the pump should be detected to prevent the starting of a dry pump.

5. A delay circuit should be provided to ensure complete priming.

6. The control should provide for at least three starting attempts (unless an overload has occurred).

7. The priming time should be limited (if under a suction lift system).

8. The control should provide for a restart in the event of a false loss of prime on startup (suction lift system).

9. Pump and motor bearings should have thermostats to stop pumps in the event of bearing failure.

10. Vibration monitoring may be important. This is particularly true for vertical pumps.

11. Pressure controls should indicate normal pressure and fail-safe in the event of a loss of pressure (broken column line, and so on).

12. Flow indication (check valve flow switch) is needed to signal a shaft failure.

13. Remote indication (generally at the mine office) should provide at least an indication of operation and signal pump failure or high water. More detailed information may be transmitted.

14. For long distances, investigate the use of carrier-current indication schemes, together with signal multiplexing, and so on.

15. Provide a method to test the control and alarm system.

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Survival Treasure

This is a collection of 3 guides all about survival. Within this collection you find the following titles: Outdoor Survival Skills, Survival Basics and The Wilderness Survival Guide.

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