KUSTERS WATER DIVISION

GRIT WASHER

The Kusters Water ProTechtor® Grit Washer is known for its reliable operation and robust design. Separation efficiencies of the grit washer are much higher than conventional grit classifiers. All ProTechtor® products are US Manufactured at Kusters Water’s ISO 9001:2015 certified facility.

PRINCIPLE OF OPERATION

The grit slurry is fed into the grit washer through the inlet. Organics material is held in suspension, captured then released via the organics reject valve. Heavier grit particles settle in the washer tank for further cleaning. With the addition of water, a stirring device and up-current wash water technique the settled grit is separated from the remaining organics constituents. The washed grit is then removed with an extraction screw, dewatered and discharged. Typical grit contains less than 3% organics and is 90% dry.

Rugged stainless steel construction
Completely enclosed
Ease of maintenance
Indoor or outdoor installation
Fully automatic operation
Optional inlet trommel screen for non-grit solids removal
Easily configured to suit existing installations
High reliability, low maintenance costs
Accepts flows up to 600 gpm without the need for primary separation
Low water consumption
Volatile solids reduction to < 3%
Separation rate of > 95% of particles 0.2 mm and up
Clean, dry, odor free grit discharge

TYPICAL SEQUENCE OF OPERATION

XGT GRIT TRAP AND VORTEX GRIT WASHER

AUTOMATIC OPERATION:

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INITIAL CONDITIONS FOR AUTOMATIC OPERATION
Control Power OFF/ON	ON
Grit Pump Hand-Off-Auto	In AUTO
Scour Valve Open-Close-Auto	In AUTO
XGT Impeller Drive OFF/ON	ON Position
Grit Washer Agitator Hand-Off-Auto	In AUTO
Grit Washer Auger Hand-Off-Auto	In AUTO
Grit Washer Grit Bed Wash Valve Open-Close-Auto	In AUTO
Grit Washer Organics Drain Valve Open-Close-Auto	In AUTO
Emergency Stops:	Not Activated

1.    The Grit Removal Cycle will be started by one of the following inputs when in the Automatic Mode:
a.    Cycle Start Pushbutton
b.    Time Clock
The Grit Pump Cycle Timer is set for the total grit cycle time - the scour time plus the pumping time. When started by the Cycle Start pushbutton or the Time Clock, the Grit Pump Cycle Timer and the Scour Valve Duration Timer will start timing, and the scour valve will open. After the Scour Valve Duration Timer elapses, the scour valve will close and the Grit Pump will start. The Grit Pump will run for the remaining time in the Grit Pump Cycle Timer.
NOTE: The Grit Pump Cycle Timer must be set for a longer duration than the Scour Valve Duration Timer for the grit pump to run.

NOTE: The Time Clock has two timers, Time Clock High Flow and Time Clock Low Flow which are dependent on the float switch (float switch is set in the field by installing contractor).
If the influent has a low flow, the Grit Removal Cycle will start when the Time Clock Low Flow timer elapses.
If the influent has a high flow, the Grit Removal Cycle will start when the Time Clock High Flow timer elapses.
2.    The Grit Washer Automatic Cycle is to be started with no delay by one of the following inputs when in the Automatic Mode.
a.    Remote Signal from the Grit Pump indicating the Grit Pump is ON
b.    Grit Pump OFF. Grit Bed Level High
When the Grit Pump is running, the Grit Washer will begin automatic operation. The Grit Agitator will start, the Wash Water Valve will open, and the Organics Drain Valve will open and close for the times set in the Organics Valve Open Time and Organics Valve Closed Time timers.
NOTE: Manually switching the Organics Drain Valve from “AUTO” to “OPEN” or “CLOSE” will not interrupt the grit washer’s Automatic Cycle.
A flow switch will monitor wash water supply and indicate if the supply fails.
When the Grit Pump stops, the Organics Drain Valve must close immediately. The Grit Washer will continue to run in automatic operation for the amount of time set in the Grit Washer Off-Delay Timer and then shut down. The Grit Agitator will stop, and the Wash Water Valve will close.
The Grit Washer Auger is controlled by the Grit Bed Level Sensor and the Grit Bed Level set points. The Grit Bed Level set points are adjustable via the HMI. Two pressure set points are entered – one for Grit Pump ON, and one for Grit Pump OFF. Two set points are required because the sensor will detect different pressures when the pump is on and when the pump is off. The Grit Washer Auger can run at any time, with or without the grit pumps running. The Organics Valve must be closed whenever the Grit Pumps are not running.
When the Grit Bed Level Sensor detects a high grit bed level for the amount of time set in the Grit Washer Auger On-Delay Timer, the Grit Washer Auger will start. The Grit Agitator and Wash Water will turn on if not running.
The Grit Washer Auger will cycle on and off for the durations set in the Grit Washer Auger On Time timer and the Grit Washer Auger Off Time timer.
Once the Grit Bed Level Sensor no longer detects a high grit bed level, the Grit Washer Auger will continue to run for the amount of time entered in the Grit Washer Auger Off-Delay timer and then shut down. The Grit Agitator will stop, and Wash Water Valve will close once the Grit Washer Agitator/Wash Water Valve Off Delay timer has elapsed.

MANUAL OPERATION of the Grit System:

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INITIAL CONDITIONS FOR MANUAL CONTROL
Emergency Stops:	Not Activated

The Grit Pump will start and run when the Grit Pump Hand-Off-Auto selector switch is in the HAND position. Placing the Grit Pump Hand-Off-Auto switch in the OFF position will stop the Grit Pump.
NOTE: If the Grit Washer is in AUTO mode, it will run per its automatic sequence when the Grit Pump is running in HAND.
Any Grit Washer motor will start and run when its Hand-Off-Auto selector switch is in the HAND position. The motor selected will remain in operation until the Hand-Off-Auto switch is placed in OFF or AUTO.
The Grit Washer Wash Water Valve will open when the Grit Washer Wash Water Valve Open-Close-Auto switch is in the OPEN position. Placing it in the OFF position will close the valve.
The Grit Washer Organics Drain Valve will open when the Grit Washer Organics Drain Valve Open-Close-Auto switch is in the OPEN position. Placing it in the OFF position will close the valve.
The XGT Impeller Drive will remain in operation as long as the XGT Impeller Drive OFF/ON switch is in the ON position. Placing it in the OFF position will stop the impeller.
NOTE: The XGT impeller is typically set to ON any time there is flow to the grit chamber.
The XGT Scour Valve will open when the Scour Valve Open-Close-Auto switch is in the OPEN position. Placing it in the OFF position will close the valve.

FAULT CONDITIONS

Emergency Stop: When activated, this pushbutton stops all automatic and manual functions. Manual reset of the pushbutton is required to resume cycle operation.
Grit Pump Fault: If the grit pump motor overload is tripped, the grit pump and grit cycle will stop until manually reset.
Grit Pump Overtemp Fault: If the grit pump motor is overheated, the grit pump and grit cycle will stop until the overtemp signal is withdrawn.
XGT Impeller Fault: If the impeller motor overload is tripped, the impeller will stop until manually reset.
XGT Impeller Overtemp Fault: If the XGT impeller motor is overheated, the grit pump and grit cycle will stop until the overtemp signal is withdrawn.
Grit Washer Agitator Fault: If the grit washer agitator motor overload is tripped, the corresponding Grit Washer Auger FAULT LED will be energized. Automatic operation will continue, but grit cleanliness will be impaired.
Grit Washer Agitator Overtemp Fault: If the grit washer agitator motor is overheated, the corresponding Grit Washer Auger OVERTEMP LED will be energized. The Grit Washer Agitator motor will stop and cannot run until the overtemperature signal is withdrawn. Automatic operation will continue, but grit cleanliness will be impaired.
The grit washer and grit cycle will stop until the overtemp signal is withdrawn.
Grit Washer Wash Water Low Fault: If the grit washer flow switch has detected low water flow, the corresponding Grit Washer Wash Water LOW LED will be energized. Automatic operation will continue, but grit cleanliness will be impaired.
Grit Washer Auger Fault: If the grit washer auger motor overload is tripped, the grit washer and the grit cycle will stop until manually reset.
Grit Washer Auger Overtemp Fault: If the grit washer auger motor is overheated, the grit washer and grit cycle will stop until the overtemp signal is withdrawn.
Grit Washer Organics Valve Fault: If the grit washer organics drain valve has failed to open or close, the corresponding Organics Valve FAULT LED will be energized. Automatic operation will continue, but grit cleanliness will be impaired.

AUXILIARY CONTACTS

XGT Impeller Running
XGT Impeller Fault
Grit Pump Running
Grit Pump Fault
Grit Washer Auger Running
Grit Washer Auger Fault
Grit Washer Agitator Running
Grit Washer Agitator Fault
Grit Washer Organics Valve Open
Grit Washer Organics Valve Fault
Grit Washer Wash Water Low
Emergency Stop

MAIN CONTROL PANEL

Power ON/OFF switch
Cycle Start (Pushbutton)
XGT Impeller OFF/ON Switch
XGT Scour Valve Open-Closed-Auto Switch
Grit Pump Hand-Off-Auto Switch
Grit Washer Auger Hand-Off Auto Switch
Grit Washer Agitator Hand-Off Auto Switch
Grit Washer Organics Valve Open-Closed-Auto Switch
Grit Washer Wash Water Valve Open-Closed-Auto Switch
Alarm Reset (Pushbutton)
Emergency Stop (Pushbutton)

Power ON (White)
XGT Impeller Running (Green)
XGT Impeller FAULT (Red)
XGT Impeller OVERTEMP (Red)
Grit Pump FAULT (Red)
Grit Pump OVERTEMP (Red)
Grit Pump RUNNING (Green)
Grit Pump in AUTO (Amber)
XGT Scour Valve OPEN (Green)
Grit Washer Auger RUNNING (Green)
Grit Washer Auger FAULT (Red)
Grit Washer Auger OVERTEMP (Red)
Grit Washer Agitator RUNNING (Green)
Grit Washer Agitator FAULT (Red)
Grit Washer Agitator OVERTEMP (Red)
Grit Washer Organics Valve OPEN (Green)
Grit Washer Organics Valve FAULT (Red)
Grit Washer Wash Water LOW (Red)

LIST OF ADJUSTABLE TIMERS & SETPOINTS

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DESCRIPTION	INITIAL SETTING	RANGE
Time Clock Low Flow	60 minutes	15 – 720 minutes
Time Clock High Flow	30 minutes	15 – 360 minutes
Scour Valve Duration Timer	1 minute	0 – 10 minutes
Grit Pump Cycle Timer	10 minutes	0 – 30 minutes
Grit Washer Agitator/Wash Water Valve Off Delay	5 minutes	0 – 15 minutes
Grit Washer Organics Drain Valve Open Time	15 seconds	0 – 60 seconds
Grit Washer Organics Drain Valve Closed Time	90 seconds	0 – 120 seconds
Grit Washer Auger Cycle On Delay	30 seconds	0 – 60 seconds
Grit Washer Auger Cycle Off Delay	2 minutes	0 – 5 minutes
Grit Washer Auger On Time	30 seconds	0 – 60 seconds
Grit Washer Auger Off Time	30 seconds	0 – 60 seconds
Grit Bed Level Sensor – ‘Grit Pump ON’	Set at Start-Up	0 – 200 mbar
Grit bed Level Sensor – ‘Grit Pump OFF’	Set at Start-Up	0 – 200 mbar