Abrasive Removal
Ebbco’s Garnet Removal System is designed to continuously remove the spent abrasive that collects in the catch tank, thus eliminating downtime for clean out. The Garnet Removal or "automatic shovel" as it is commonly referred to, can be retrofitted to any abrasive waterjet cutting machine tool. The system is sized by the area (in square feet) of the catch tank, and by the high-pressure pump capabilities versus the size of the catch tank. The primary selling feature of the Ebbco Garnet Removal System is to eliminate downtime on the machine tool and maximize production. The Ebbco Abrasive Removal System comes with a choice of spent abrasive receivers, depending on the end user disposal procedures. A 55 gallon drum, self dumping hopper or bulk abrasive bag hopper give our customers different options on how to handle the spent abrasive. The last option, the bulk abrasive bag hopper, is rapidly becoming our most popular due to the ease of handling and the eliminating of the use of dumpster's and local landfills for the disposal of spent garnet. Depending on your local geographic area Ebbco can help set up a disposal / recycle program for the spent abrasive in your bulk abrasive bags. This abrasive removal / recycle / disposal program takes care of many negatives in dealing with abrasive waterjet machines:
The downtime and "lousy" job of shoveling out catch tanks.
The transfer of spent abrasive from the catch tank to the dumpster.
The overfilling of dumpster's and local waste haulers not being able to pick it up to dump it.
The breaking of dumpster's.
The landfill concerns due to the metal content of the spent abrasive.
Your closed loop system becomes your abrasive removal system sending your closed loop systems operating cost up very high.
Many Waterjet manufacturers are supplying overflow to drain or closed loop recirculation systems to handle table overflow water as part of the machine tool package or as an option. This is due to the fact that many states and local municipalities are restricting abrasive waterjet users from overflowing the table water into the POTW (Public owned treatment works). This water contains garnet, metal particles and dissolved solids from the machining process. When the catch tank fills with garnet it displaces the water in the tank. The overflow water now has a much higher concentration of garnet and suspended solids overflowing from the table, not to mention that due to less water, the catch table water temperature will increase. If you are using an overflow to drain system or a closed loop system to filter the table overflow water, the higher concentration of solids will result in increased consumables (filters and D.I. resin) for these systems. Another important purpose for the water in the catch tank is to dissipate heat incurred from the cutting process. When this water is displaced with garnet, the remaining water will not dissipate heat as efficiently, which could result in extreme water temperatures, resulting in thermal distortion of the part that is being cut. As waterjet systems continue to increase their capabilities, such as multi-axis cutting and closer tolerance’s being held, the need for reduced thermal distortion by controlling the catch tank temperature will increase.
EBBCO’S GARNET REMOVAL SYSTEM – HOW IT WORKS
The Ebbco sweeper package is installed in the bottom of the catch tank. This Sweeper Package incorporates a 4 to 1 Eductor, which enhances water flow and keeps the garnet in suspension pushing it toward the pump suction. The slurry is pumped through a centrifugal separator to remove suspended solids. The solids are purged into a self-dumping hopper, 55-gallon drum or bulk abrasive bag hopper depending on the company’s disposal method. The hopper/drum overflows back to the catch tank. Since the centrifugal separator has no moving parts, this filtration system has no consumables. This system should be turned on before the cutting starts, and turned off well after the cutting stops. The Ebbco Garnet Removal System has a full one-year warranty on the entire system including the pump, which is unprecedented in this industry. Two year and three year extended warranties are also options.
The Garnet Removal System is a necessary evil, however, with most shops a reasonable system payback is easily obtained, especially when eliminating local waste haulers and local landfills. If any of these concerns apply to your company, please call us.
WASTE DISPOSAL PROCEDURE FOR ABRASIVE WATERJET CUTTING
SPENT ABRASIVE
Take a sample (usually four or five pounds will do) of the spent abrasive to a local certified test lab for a TCLP test.
A toxicity characteristic leeching procedure (TCLP) will give a breakdown of heavy metals from your spent abrasive sample.
Contact your local waste (Waste Management, BFI, etc.) hauler Representative.
Explain to your local waste hauler representative what you have (spent abrasive sample and TCLP results).
Have your rep give you a legal allowable limit sheet on hazardous metals for your local Landfill.
You and your rep will determine if your company is within the guidelines for normal waste hauling.
Note: In many parts of the country, even if your local waste hauler cannot or will not take the spent abrasive, it does not mean that it is classified as hazardous. Many states have "lined" landfills for industrial waste with heavy metals yet not hazardous waste. Your local waste hauler should be able to make a recommendation.
If your rep determines that you can dispose of it in your dumpster, have him put it in writing,.
This letter along with your TCLP test should be kept on file in your facility, if by chance your company was ever questioned by local authorities or the EPA.
Normally, TCLP test are good for one full year from the test date as long as your cutting procedure has not changed. Consult your local testing lab for validity of test length and make sure it's dated.
WATER SAMPLE FROM TABLE OVERFLOW
Take a sample (usually a pint or quart will do) of your table overflow water to a local test lab for a TCLP test.
Contact your local wastewater facility. (Normally where you pay or send your water bill to).
Ask them for a legal allowable limit sheet for your local wastewater.
Verify your TCLP test results with your local wastewater spec sheet. If you are within the guidelines you can discharge into the drain.
If you're not within local guidelines a try settling system and have the water re-tested and compare with your local wastewater spec sheet.
If you still are not within the local guidelines you have two options.
Treat the water (DI or chemical treatment) and then perform another TCLP test and discharge into the drain. If it fails see option 2.
Purchase a closed loop recirculation system and reuse all the process water.
Note: In most cases the operating (filter) costs on a closed loop system are lower than treating the water and going to drain.
