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Batch Cleaner Closed Loop YES!!! / NO!!! / MAYBE???


Batch Cleaner Closed Loop YES!!! / NO!!! / MAYBE??? | 14 February, 2002

Has anyone looked at the economics of running a 2meg [min] DI water batch cleaner ... * Open loop * Closed loop

What are the assumptions of your analysis?

Our inclination is that it is not worth the money to set-up and maintain a closed looper.

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Batch Cleaner Closed Loop YES!!! / NO!!! / MAYBE??? | 15 February, 2002

The Electrovert AquaJet w/ Closed-Loop runs like $63K to $107, depending on the AJ config. The AJ is like the only batch machine I've seen that is not a glorified dish washer. Justification depends on your application. The batch system takes less space and lower cost to operate vs. in-line systems.

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Mike Konrad


Batch Cleaner Closed Loop YES!!! / NO!!! / MAYBE??? | 15 February, 2002

Hi Dave,

To close-loop or not to close-loop, that is the question�

I can not speak for all machines, but in our case, close-loop systems are actually less costly to operate than open-loop systems (we make both).

First, determine the volume of water used in an open-loop cleaner. For instance, if the cleaner�s sump capacity is 2 gallons, and you run 1 wash cycle and six rinses, you can determine that for each batch of boards, you will need 14 gallons of DI water.

Secondly, do you have an existing DI water source? If not, you will most likely rent one from US Filter (or similar company) for an average cost of $ 70.00 per month, plus bottle exchanges. Here�s a formula based on a hypothetical requirement:

Water used per load of boards: 14 gallons Batches run per day: 10 Water used per day: 140 gallons Water used per month: 3010 gallons Quality of incoming tap water: 500 ppm Grain capacity of typical resin-based rental DI system: 30,000 grains Grains per gallon of tap water (ppm / 17.1): 29 grains per gallon Volume capacity of DI filter beds: 1,034 gallons (30,000 / 29)

Based on the above hypothetical, you will be replacing your DI tanks about 2 times per month. Most DI rental companies charge between $ 50.00 and $ 75.00 to exchange tanks. Lets call it $ 100.00 per month in tank exchanges plus $ 70.00 per month in rental charges. That�s $ 170.00 per month $ 2,040.00 annually) for DI water.

Now, lets compare a closed-loop system. A closed-loop batch cleaner excepts tap water on its initial fill (ours holds about 20 gallons). The closed-loop cleaner automatically de-ionizes the water and uses it over and over again to clean boards. When boards are being cleaned, two processes take place simultaneously. First, water is drawn from the sump tank and is directed onto the boards through the spray nozzles. Secondly, another pump draws water from the sump tank and directs it through a DI system. As the process water sprays onto the boards, it gets contaminated with flux and other contaminants. These contaminants are removed via the closed-loop DI system. Over the course of several minutes, the water in the sump becomes cleaner and cleaner, turning back into DI water.

When DI water is sprayed onto contaminated boards, it becomes dirty. Dirty DI water, however, is many times cleaner than �clean� tap water. It is far easier on a DI system to �clean-up� or re-de-ionize used DI water then it is to de-ionize tap water. This results in longer filter life. The average cost for a year�s worth of DI filters on a batch closed-loop system is $ 1,185.00 (about half the cost of an open-loop system).

As with all things in life, there are compromises.

Open-Loop System Pro�s: 1. Compatible with all flux types. 2. Compatible with water soluble solder masks.

Open-Loop System�s Con�s: 1. Drain = liability. 2. Uses more water. 3. Higher DI filter cost. 4. Longer cycle times.

Closed-Loop System�s Pro�s: 1. No drain = no liability. 2. Uses less water (only make up for evaporation). 3. Lower DI filter cost. 4. Shorter cycle times.

Closed-Loop System�s Con�s: 1. Inflexible applications (water soluble flux only, no water soluble mask).

I hope this helps!

This message was posted via the Electronics Forum @

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Sean D


Batch Cleaner Closed Loop YES!!! / NO!!! / MAYBE??? | 15 February, 2002

Hello Dave,

With regards to acquiring data and additional insight to cost of ownership and your technical concerns for closed loop recirculation, a good contact for you may be Brian Mahue of Resys. Resys specializes in closed loop recirculation systems as well as heat recovery systems and reverse osmosis purification systems and Brian is a great source to tap for information.

You can reach him at: 800-873-7379 For more information on Resys: They are based in Salem, OR

Good luck, Sean D

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