Using Proper Distribution Systems – Tank Internals
The least expensive component of a water system is the most critical component. The distributor tube system plays a vital role in the filtration and softening process. Using a poorly designed distributor system is like trying to drink through a cocktail straw rather than a standard size you might get with a cold drink.
The distributor system (aka tank internals) plays a vital role in the performance of all water conditioners regardless of size. Typical problems of poorly designed or manufactured distribution systems include:
- Pressure loss at peak flows
- Channeling of the conditioning media – resin, carbon, neutralizing media, etc.
- Inefficient operation, poor backwash, shortened cycle times
- Complete failure due to media loss which may result in thousands of dollars in clean up for the home or business owner.
What’s in your tank?
Riser Tube, Standpipe, Distributor Tube
- A distributor tube consists of a plastic or stainless-steel tube and is attached to a distributor, also called a diffusor, collector or basket.
- Its purpose is to produce even flow through an ion exchange or filter media bed.
- A distributor tube retains the media in the tank.
- The basket screen size is determined by the system media.
- The distributor tube length to match the tank size and valve.
Hub & Lateral Tank Internals
- For systems with 14″ or greater tanks use hub and lateral distributors.
- Hubs and laterals are available in PVC, ABS, Poly Pro and Stainless Steel.
- Valve size dictates distributor size and the distributor size dictates the size of the hub.
- Laterals for filters and ion exchange differ in slot size.
- Filter media type and backwash rates vary and usually require a slightly larger slots than ion exchange resin.
- Ion exchange laterals usually have .010” slots whereas filter laterals slots are .020”.
- Filter media type and backwash rates vary and usually require a slightly larger slots than ion exchange resin.
- Performance of large commercial and industrial systems is impacted by distribution design.
Bottom “Plate” Distributor
This is a proprietary high flow, high efficiency type distributor which uses the entire tank bottom rather than a tube type with a strainer at the bottom. It’s only available as part of a complete system. Because you’re using the entire tank bottom the flow rate potential increases. The water is distributed evenly throughout the bed allowing for improved efficiency.
When to Use Gravel Sub-Fill
| Equipment | Yes/No | Comment |
|---|---|---|
| Carbon Filters - Backwashable Type | Yes | If recycling carbon, separation of gravel from carbon is required. |
| Carbon Filters VOC Removal | No | Backwashing a carbon filter used for VOC removal will upset the mass transfer zone and may result in leakage of the contaminants. |
| Acid Neutralizers | Yes | Upflow & Downflow systems |
| Softening - Upflow | No | N/A |
| Softening - Downflow | Yes | Creates a better flow pattern. |
Common Problems
- Decreased flow due to pressure drop. This usually happens in a commercial industrial setting but may occur in a residence. It’s important to know the peak flow rate for all applications.
- Clogged slots/screens – slot size may be too small or too large for media.
- Fouled media bed due to lack of good backwash – The water goes down the tube, out the strainer slots, up through the bed and down the drain. If the distribution system isn’t properly sized there isn’t enough water volume and pressure to lift the bed.
- In a commercial industrial setting:
- Pressure drop increase may gradually occur. Enough crud builds up to reduce the flow rate or affect water quality. Service companies need to evaluate the internals prior to replacing the media. At the very least the hub and laterals should be cleaned but it’s a good idea to contact an experienced equipment design company to determine whether the current internal system can do the job.
- Broken laterals as a result of poor quality and/or application design, improper support bed or installation.
Urbans Aqua offers standard and custom distribution systems.
If you are a water treatment dealer, plumber or well driller and have questions regarding this post contact Michael Urbans @ 610-365-7818. Contact Us
Urbans Aqua is a stocking wholesaler of Residential & Commercial Water Treatment Equipment and Supplies including Purolite , Thermax and ResinTech Ion Exchange Resin; Calgon & Jacobi Activated Carbon; Filterag Plus; GreensandPlus; Pyrolox Advantage; KDF; Birm; Sand/Gravel; Clack, Fleck, Autotrol & AqMatic valves; Stenner Pumps & Parts.
Urbans Aqua sells exclusively to water treatment professionals. We do not deal with the general public.