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D I S C F I L T R A T I O N
SPIN DISC
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The Most Efficient Self-cleaning Filtration
A2 offers
the reliable Arkal Disc Filtration System for filtering industrial
process and wastewater. It is one of the most efficient filtration systems
available. The Spin Disc system operates using a specially designed disc
filtration technology. Thin, color-coded polypropylene discs are diagonally
grooved on both sides to a specific micron size. A series of these discs are
then stacked and compressed on a specially designed spine. When stacked, the
groove on top runs opposite to the groove below, creating a filtration
element with a statistically significant series of valleys and traps for
solids. The stack is enclosed in a corrosion and pressure resistant housing.
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Spin Disc Features:
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Low Backwash Volumes
Continuous supply of filtrate during backwash
Elements do not need replacing
A simple element change for filtration grade adjustments
Modular units fit any space and can expand or retract easily
10 to 400 micron filtration size
Small Footprint
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SPIN DISC TECHNOLOGY
OPERATION
The Spin Disc compressed disc stack retains particles while clean filtrate
passes. Once the element is loaded with particles, the backwash cycle
initiates automatically. First, the reversal of the water flow decompresses
the disc stack allowing the discs to move freely. Then, a series of nozzles
spray a mixture of high pressure water and air on the disc grooves, causing
them to spin rapidly. The combination of the spray and spinning action
cleans the discs very quickly.
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Normal Filtration
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Click on image for animation |
During normal filtration the discs are tightly compressed together by the
spring's power and the differential pressure, thus providing high filtration
efficiency.
Filtration occurs while water is percolating from the outer diameter to the
inner diameter of the element.
Depending on the micron rating, there are from 18 (in 400 micron discs) to
32 (in 20 micron discs) stopping points in each track, thus creating the
unique in-depth filtration.
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Backwashing Filtration
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Activated by a control signal, alternate units of the Spin Disc system go
into backwash operation. The inlet valve is shut as the drain is
automatically opened.
During backwash, the compression spring is released. The spin piston rises
up, releasing the pressure on the discs.
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Tangential jets of clean water are pumped at high pressure in the opposite
direction through nozzles at the center of the spine. The discs spin free
and clear, loosening the trapped solids. Solids are quickly and efficiently
flushed out through the drain.
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Click on image for animation |
BACKWASH TYPES:
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| Standard Source |
Standard source backwash uses filtrate from the other filter "pods" on the filter battery as the water source to backwash each "pod". In the standard source backwash process, one pod in the filter battery is isolated from the inlet water via a three-way valve. This same three-way valve is opened to a drain manifold through which the backwash water will leave the backwashed filter pod. A portion of the filtrate from the other pods in the filter battery is then diverted back through the pod being backwashed. The backwash flow is in the opposite direction of the flow when the pod is filtering water, so that the filter is backwashed clean. The dirty backwash water leaves the pod and flows out through the three-way valve into the drain manifold where it is discharged from the system. Once the first pod is backwashed, it is brought back "on line" by changing the three-way valve back to the inlet manifold and then isolating the next pod on the filter battery for backwashing. In this way the complete filter system is backwashed - one pod at a time - so that even during backwash the filter system is still filtering water.
Benefits:
Low cost.
Backwash is fast and efficient
No need for external source of water
Easy maintenance
Limitations:
Inlet feed water pressure must be consistently above 70 psi for fine discs, or 60 psi for coarse disc filtration.
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| External Source |
External source backwash uses an external source of clean water (potable water, fire water, stored filtrate, etc.) as the water source to backwash each "pod". In the external source backwash, one pod in the filter battery is isolated from the inlet water via a three-way valve. This same three-way valve is opened to a drain manifold through which the backwash water will leave the filter pod. At the same time, the pod is isolated from the outlet manifold via another three way valve. This three way valve is opened to an "external source" manifold. When the external source manifold is opened, backwash water from the external source is forced back through the pod being backwashed. The backwash flow is in the opposite direction of the flow when the pod is filtering water, so that the filter is backwashed clean. The dirty backwash water flows out through the three-way valve into the drain manifold where it is discharged from the system. Once the first pod is backwashed, it is brought back "on line" by changing both three-way valves back to the inlet and outlet manifolds and then isolating the next pod on the filter battery for backwashing. In this way the complete filter system is backwashed - one pod at a time - so that even during backwash the filter system is still filtering water.
Benefits:
Can use any clean water source
Feedwater pressure and flow can vary without impacting backwash process
Pressure can be controlled to ensure proper backwash water pressure
Easy maintenance
Limitations:
Slightly more expensive than the "Standard Source" backwash technique.
Must have pressurized backwash water system.
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| Air Assist |
Air assisted backwash uses a stored volume of filtrate as the backwash water source to backwash each "pod". In the air assisted backwash, the valve configuration is the same as the external source backwash technique: one pod in the filter battery is isolated from the inlet water via a three-way valve. This same three-way valve is opened to a drain manifold through which the backwash water will leave the filter pod. At the same time, the pod is isolated from the outlet manifold via another three way valve.
This three way valve is opened to an "external source" manifold.
During filtration, a volume of filtrate is stored in an "on-board" storage reservoir. This stored volume of filtrate is the water that will be used for backwashing each pod. When a backwash is initiated, the external source manifold is opened and backwash water from the filtrate reservoir is forced back through the pod being backwashed using compressed air. The compressed air is connected to the filtrate reservoir via a two-way valve that opens when the backwash process is initiated to force the water back into the filter battery. The backwash flow is in the opposite direction of the flow when the pod is filtering water, so that the filter is backwashed clean. The dirty backwash water flows out through the three-way valve into the drain manifold where it is discharged from the system. Once the first pod is backwashed, it is brought back "on line" by changing both three-way valves back to the inlet and outlet manifolds. After the first pod is backwashed, the filter delays initiating the second pod for a few seconds to allow the reservoir pod to refill with clean filtrate water. Once the reservoir is filled, the next pod on the filter battery is isolated for backwashing. In this way the complete filter system is backwashed - one pod at a time - so that even during backwash the filter system is still filtering water.
Benefits:
The absolute lowest backwash water volume requirement of any filtration system
Feedwater pressure and flow can vary without impacting backwash process
Pressure is controlled using compressed air to ensure proper backwash water pressure
Air/water mixture creates an extremely aggressive backwash for superior cleaning
Easy maintenance
Limitations:
Slightly more expensive than the "External Source" backwash technique.
Must have compressed air at 80 psi at approximately 24 cfm (used for approximately 5 seconds per pod).
Footprint is the same but the system is slightly taller
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SPIN DISC PRODUCTS
2" Spin Disc Compact Stand-alone Unit
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| Capacity: |
Small Flow (35-90 gpm)
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| Operation: |
Fully Automatic Disc Filtration Unit
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| Material: |
Polyester Coated
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Backwash types available for this unit include:
Standard Source, External Source, and Air Assist
CLICK HERE OR SCROLL DOWN FOR HEAD LOSS CHARTS
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2" Spin Disc Standard Unit
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| Size: |
3" - 6" inlet/outlet diameter
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| Capacity: |
Low flow (45-530 gpm)
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| Operation: |
Modular, Fully Automatic Disc Filtration System
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| Material: |
Polyester Coated or Stainless Steel
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Backwash types available for this unit include:
Standard Source, External Source, and Air Assist
CLICK HERE OR SCROLL DOWN FOR HEAD LOSS CHARTS
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Head Loss Chart
2" Spin Disc - In Clean State
| 1 - Blue | (400 MICRON / 40 MESH) |
| 2 - Yellow | (200 MICRON / 80 MESH) |
| 3 - RED | (130 MICRON / 120 MESH) |
| 4 - BLACK | (100 MICRON / 140 MESH) |
| 5 - GREEN | (55 MICRON) |
| 6 - GREY | (20 MICRON) |
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3" Spin Disc Standard Unit
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| Size: |
4" - 10" inlet/outlet diameter
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| Capacity: |
Medium flow (400-880 gpm)
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| Operation: |
Modular, Fully Automatic Disc Filtration System
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| Material: |
Polyester Coated or Stainless Steel
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Backwash types available for this unit include:
Standard Source and External Source
CLICK HERE OR SCROLL DOWN FOR HEAD LOSS CHARTS
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3" Spin Disc Star Unit
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| Size: |
3" Spin Disc compact batteries
8" - 12" inlet/outlet diameter
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| Capacity: |
High flow (880-2,600 gpm)
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| Operation: |
Modular, Fully Automatic Disc Filtration System
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| Material: |
Polyester Coated or Stainless Steel
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Backwash types available for this unit include:
Standard Source and External Source
CLICK HERE OR SCROLL DOWN FOR HEAD LOSS CHARTS
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Head Loss Chart
3" Spin Disc - In Clean State
| 1 - Blue | (400 MICRON / 40 MESH) |
| 2 - Yellow | (200 MICRON / 80 MESH) |
| 3 - RED | (130 MICRON / 120 MESH) |
| 4 - BLACK | (100 MICRON / 140 MESH) |
| 5 - GREEN | (55 MICRON) |
| 6 - GREY | (20 MICRON) |
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4" Spin Disc Galaxy Unit
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| Size: |
4" - 10" inlet/outlet diameter
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| Capacity: |
Medium flow (400-880 gpm)
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| Operation: |
Modular, Fully Automatic Disc Filtration System
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| Material: |
Polyester Coated or Stainless Steel
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Backwash types available for this unit include:
Standard Source and External Source
CLICK HERE OR SCROLL DOWN FOR HEAD LOSS CHARTS
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Head Loss Chart
4" Spin Disc - In Clean State
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