15 High Rate Mixing Pump Start Up
Typically, the High Rate Mixing Pumps run in automatic mode, 24 hours per day, seven days per week.
To mix the sludge in the digesters and maintain a consistent temperature.
Watch for open tanks and high elevations. If working on or near equipment, watch for rotating parts. Watch for tripping hazards and overhead piping while manipulating the valves.
Use caution when rotating valves. Valves must be opened and closed in a particular order. The first step should always be to open a valve. If the operator’s first step is to close a valve, there is a risk that two valves on that pressure system may be closed. If this happens, pressure sensors should signal an alarm. The worst case scenario is that the high pressure created in the closed pressure system would cause damage and/or failure of the system. Warning: always verify which valves are open and closed before making any changes.
Operator I, knowledge of digestion process and equipment controls.
- Key or other tool to open/close valves.
- Record activity to log book.
1. Unlock and untag the equipment being put back into service.
a. Check the equipment and immediate area to ensure that nonessential items have been removed. Verify that the equipment and its components are operationally intact.
b. Check the work area to ensure that all employees are safely positioned or outside the area.
c. Verify that the controls are in neutral.
d. Remove the locks, tags and lockout devices and reenergize the equipment. Reverse the order of the Lockout-Tagout Procedure. Click here for the Lockout-Tagout SOP.
2. Verify Suction and Discharge Valve Status.
a. Each High Rate Mixing Pump system is equipped with two isolation suction valves: a bottom suction valve {tag no. 1505VLV5100 & 1505VLV5200) and a top suction valve {tag no. 1505VLV5100A & 1505VLV5200A}. The valve to be opened will depend on the valve rotation schedule – refer to the Mixing Valve Rotation Schedule that is posted on the wall of the Solids Building. Open the appropriate suction valve. One suction valve should be open and one suction valve should be closed.
b. Each High Rate Mixing Pump is equipped with one isolation discharge valve {tag nos. 1505VLV5100F & 1505VLV5200F}. Open the discharge valve.
3. Inspect the pump(s) {tag nos. 1505PMP5100 & 1505PMP5200} to be put into operation.
a. Make sure nothing is impeding the pump’s motor {tag nos. 1505MTR5100 & 1505MTR5200}. Check for proper movement.
b. Monitor the suction pressure gauge {tag no. 1505PI5100 & 1505PI5200} and discharge pressure gauge {tag no. 1505PI5100A & 1505PI5200A}.
c. The High Rate Mixing Pumps have been upgraded and no longer require seal water. Seal water piping is still in place, but has been abandoned.
4. Set local controls.
a. Each High Rate Mixing Pump is equipped with a push button Lock Out Switch (LOS) {tag nos. 1505HS5100A & 1505HS5200A} and a Disconnect Switch {tag nos. 1505HS5100 & 1505HS5200}. Both switches are installed at a stantion, located adjacent to the pump.
b. Place the Lock Out Switch {tag nos. 1505HS5100A & 1505HS5200A} in the “Non-Stop” position by pulling the plunger out.
c. Turn the disconnect Switch {tag nos. 1505HS5100 & 1505HS5200} to the ON position.
5. Start pump(s) at the control panel. The High Rate Mixing Pump controls are located on MCC-5 in the Digester Control Building.
a. Locate the Control Bucket {tag nos. 1505BKT5100 & 1505BKT5200} for the pump(s) to be started.
b. Place the Main Breaker {tag nos. 1505BKR5100 & 1505BKR5200} in the ON position.
c. Turn the On/Off Switch {tag no. 1505HS5100B & 1505HS5200B} to the ON position.
d. The red fault indictor light will come on if the pump faults. It the pump faults, push the Reset Button {tag no. 1505HS5100C & 1505HS5200C}. The green indicator light should come on when then pump starts running.
6. Observe High Rate Mixing Pump Operation:
a. Listen for excessive noise or vibration.
b. Check for oil or process fluid leaks.
7. Record Data to Operator’s Log Book: Record High Rate Mixing Pump Activities to the log book with other entries for the day. Include the following in the entry:
· Operator(s) that performed the High Rate Mixing Pump SOP.
· Note condition of equipment, piping, valves, etc.
· Note any unusual conditions with flows, levels, odors or other process issues.
· Note any damage, wear, or required maintenance on equipment.
- Update log book.
- Update maintenance records (if applicable).
- Report any maintenance or attention that is required.
The pumps run constantly.
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