MICROSCREEN

Microscreen Setup

Proper setup of the Microscreen involves adjusting two devices to ensure effective draining of solids through the screen surface. These devices are the floc tank adjustment and the screen angle adjustment.

1. FLOC TANK ADJUSTMENT:

·       The spillway of the floc tank must be level to ensure even flow of chemically treated manure across the screen surface.

·       If the spillway is not level, flocculated manure can accumulate and hinder the flow of manure across the entire screen surface.

·       Uneven flow can result in solids at the end of the screen retaining a higher level of entrained liquids.

2. SCREEN ANGLE ADJUSTMENT:

·       The Microscreen angle is set to 35 degrees to the base and is not adjustable. This has been set to allow sufficient time for liquids entrained in the solids to drain through the screen.

·       The microscreen base must be level to ensure even flow of chemically treated manure across the screen surface.

·       If the base is not level, flocculated manure can accumulate to one side or flow faster/slower and hinder the flow of manure across the entire screen surface.

·       Uneven flow can result in solids at the end of the screen retaining a higher level of entrained liquids.

·       This ensures that the manure moves ahead of the washer spray, allowing adequate drainage of the entrained liquids.

·       By ensuring a level spillway in the floc tank and adjusting the screen angle appropriately, you can optimize the draining process and prevent issues such as uneven flow or excessive liquid retention in the solids.

Microcreen Operation

After ensuring a level floc tank and microscreen base, the next step is to optimize the chemistry settings to achieve efficient drainage of flocs and a clean filtrate. Please follow the instructions in the “3. CHEMISTRY SETTING AND ADJUSTMENT”.

MICROSCREEN MAINTAINANCE

Proper maintenance of the Microscreen is essential to ensure its optimal performance and longevity. Follow these guidelines for Microscreen maintenance:

1.     FILTRATE TANK CLEANING:

·       Drain and clean the filtrate tank (V-170) daily to remove solids buildup.

·       After cleaning, fill the P-170 suction compartment of the filtrate tank with clean water.

2.     SCREEN INSPECTION AND CLEANING:

·       Inspect the screens daily for any buildup of solids or material that is not being removed by the automatic spray bars.

·       Use a pressure washer to direct the spray onto the screen and dislodge any solids that have accumulated.

3.     SCREEN MAINTENANCE:

·       Inspect the screens weekly for damage or scale buildup.

·       Replace damaged screens as soon as possible.

·       To remove scale buildup, soak the screen in a descaler solution or a 5% Hydrochloric acid solution after removing it.

4.     SPRAY NOZZLE INSPECTION:

·       Inspect the spray nozzles daily for blockage.

·       Clean any blocked sprayers immediately to ensure proper functioning.

5.     BEARING LUBRICATION:

·       Grease the chain drive bearings weekly for proper lubrication.

·       Grease both the inner and outer bearings (Chain guard may need to be removed).

·       Grease the pillow block bearings monthly until the first indication of grease purging from either lip seal.

·       Use an NLGI No 2 grease for all bearing greasing.

6.     GEAR REDUCER OIL CHANGE:

·       Change the gear reducer oil in the microscreen and floc tank reducers annually.

·       Use Mobil SHC 634 synthetic oil for the gear reducer oil change.

·       The microscreen reducer requires 18.74 oz of oil for a complete change, while the floc tank reducers require 102.55 oz each.

SCREEN REMOVAL

Follow these steps to safely remove the screen from the Microscreen:

1. Unbolt the wing nuts and remove the side clamps from the Microscreen.
2. Unbolt the screen top clamp.
3. Loosen the screws holding down the screen bottom clamp.
4. Carefully lift the screen out of the top and bottom clamps and remove it from the system. Take care not to damage the screen during this process.

While the screen is removed, you may choose to also service the spray nozzles.

CHAIN TENSION

Follow these steps to check and adjust the tension of the driving chain on the Microscreen:

1. Remove the stainless steel guards fastened to the frame of the screen to access the driving chain.
2. Inspect the chain for any signs of wear. Check the tension of the chain, ensuring it is not resting against the bottom pan of the Microscreen.
3. Adjust the tension by increasing or decreasing the spring tension on the bottom sprocket. Rotate the bolts attached to the spring bracket on the Microscreen to achieve the desired tension. Be cautious not to over-tension the chain, as it can lead to increased wear.
4. If replacement is necessary, use #60 Stainless Steel Roller Chain.

MICROSCREEN OPERATION TROUBLESHOOTING

NO FLOC FORMATION          

If floc formation is not occurring in the process after system startup, follow these troubleshooting steps to identify and resolve the issue:

1. INSPECT CHEMICAL PUMP OPERATION:

• Verify that the chemical pumps are active and effectively pumping chemicals into the process.
• Check the suction and discharge lines of the chemical pumps for the presence of air bubbles. Air in these lines can hinder the proper performance of the pumps.
• If the chemical pumps are operational and no air bubbles are present, proceed to the next step.

2. CHECK CHEMICAL PUMP SETTINGS AGAINST CHEMICAL DOSES:

• Ensure that the chemical pumps are properly set to deliver the correct dosage of grō polymer into the system.
• Use the flow meter on the polymer piping to measure the flow rate and compare it to the expected flow rate displayed on the touchscreen.
• Verify that the VFD (Variable Frequency Drive) parameters are correctly set for the chemical pumps.
• If the chemical pump settings are accurate, proceed to the next troubleshooting step.

3. CHECK RAW MANURE CONDITIONS:

• Collect a sample of the raw manure and measure the Total Suspended Solids (TSS) and pH levels.

·       Compare these measurements to the conditions specified in the “3. CHEMISTRY SETTING AND ADJUSTMENT” 

• Assess if there have been significant changes in the manure conditions that could be affecting floc formation.
• Make any necessary adjustments to the chemistry settings based on the comparison.

Spraybar Troubleshooting       

The spray bar is a critical component for effective backwashing and maintaining optimal screen performance. If the spray bar encounters any issues, it can significantly impact the overall performance of the screen. Operators must troubleshoot and identify the root cause of any spray bar problems to promptly implement the necessary solutions and ensure the uninterrupted operation of the system.

1.    Spraybar Is not moving up and down the screen

If the spraybar is not moving, it can hinder the backwashing process. Follow these steps to troubleshoot and address the issue:

·       Verify the functioning of the G170 Variable Frequency Drive (VFD) and reset any overload situations on the VFD. Observe the chain drive system to identify the cause of motor overloading, and address it accordingly.

·       Check the chains to ensure they are intact and free from slippery or broken links.

·       Verify the timing on the chains to ensure there is no timing difference between the two chains that could cause crooked movement of the spray bar.

·       Ensure that the spray bar components are not in contact with any frame or grid members, as this may exert extra resistance and hinder the movement of the spray bar.

·       Ensure that the spray bar feet are adequately greased to minimize friction and ensure smooth movement of the spray bar.

2.     Spraybar Is not moving or Spraying  

Within the V-170 tank, there is a recirculation water compartment that supplies water to the P-170 recirculation pump. In the event of a low or empty water level, the control system will automatically disable P-170 and G-170 until the water level is restored. This safety feature ensures that the system operates efficiently and prevents any potential issues arising from inadequate water supply. Follow these steps to troubleshoot and resolve the problem:

·        Check to ensure the G-170 VFD has not been tripped. Address any issues accordingly.

·        Verify if the recirculation water compartment in V-170 is empty or has a low water level. If so, fill it with clean water and adjust the screen chemistry as necessary.

·        Check if the level switch LS-1701 is stuck and providing a false signal of an empty compartment. Adjust the level switch location if necessary.

·        Ensure that the cable of the LS-1701 switch is not damaged. If required, replace the level switch to resolve the issue.

3.     Spraybar is Moving But Not Spraying            

If the spray bar is moving but there is no spray, please follow these troubleshooting steps:

·       Check and verify that all spray nozzles are clear and not clogged.

·       Drain V-170 and ensure that the suction opening to P-170 is clear from any buildup or obstructions.

·       Verify that the ball valve on the discharge end of P-170 is not accidentally turned off, allowing proper flow.

·       Check if P-170 is running properly and delivering the necessary water pressure.

·       Ensure that there is no air trapped in the P-170 pump, as it can affect its performance.

·       Verify that P-170 pump is receiving proper power supply and operating correctly.

·       If necessary, disassemble P-170 to inspect the pump impeller for any damage or blockage.