Tag Archives: 16-020

16-020 heat exchanger 12″ deionizer cartridge issue

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The 16-020 heat exchangers are used with the older Physical Electronics (PHI) 5100 through 5400 X-ray photo-electron spectrometer (XPS) systems.The 16-020 has a built-in deionizer cartridge (and a particle filter) which keeps the water in the closed loop system clean and it also keeps the resistance of the water high. 

The original deionizer cartridges were blue and had a recess in the bottom of the filter that matched up with a plastic guide on the bottom of the Millipore housing.  Those blue deionizer cartridges are no longer available. The new replacement deionizer cartridges do not have a recess on the bottom.

When a new deionizer cartridge is used with the original Millipore housing the plastic guide on the bottom of the housing will push up on the bottom of the deionizer.  This makes it difficult if not impossible to fully screw on the housing.  It also puts pressure on the bottom of the deionizer cartridge which can rupture the bottom of the deionizer and cause the media particles to leak out, potentially causing an issue with the water flow and or damage the pump and lead to a catastrophic anode melt down. There are two ways to solve this fit issue. One is to cut and grind out the top part of the guide on the original Millipore housing. To do that you need to remove the plug on the bottom of the housing and then use a drill or cutting wheel that is mounted on a drill extension. The pictures below show a housing before and after modification.

 

The other option is to replace the original Millipore housing with new housing that correctly fits the new deionizer cartridge. But if you replace the housing you will also need to replace the manifold as the new manifold will not fit into the original Millipore manifold.

RBD Instruments provides both deionizer cartridges and housings. If you have the original Millipore housing on your 12” deionizer cartridge then I recommend that you inspect it to see whether the guide on the bottom has been cut down or not.  If not, you should cut it down or replace the housing.  

If the deionizer is ruptured then the entire cooling system (reservoir, pump, water lines and source) needs to be inspected and flushed out.This problem is an issue only with the 12″ deionizer cartridge on the 16-020 heat exchangers. 

The 16-050 heat exchanger that is used on the 5600 and up XPS systems has a 10″ deionizer cartridge.

Not sure if you need to replace your deionizer cartridge?  Just run up the high voltage on your X-ray source to 15kV but do not set an power to the X-ray source.   Observe the emission current reading on the HV supply.  If the deionizer is good the reading will be 1-2 mA.  Once the leakage current gets up to 3-4 mA at 15kV you should plan on replacing the deionizer cartridge and particle filter soon.  If the leakage current at 15kV is 5 mA or higher you should replace the deionizer and particle filter and also flush out the water with new distilled water from a grocery store.  Lab distilled water does not always work but grocery store distilled water works every time.

Contact RBD Instruments to order the deionizer and particle filter.

Deionizer flow restrictor

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Deionizer flow restrictor for PHI X-ray source heat exchangers

This post is a reprint of a tech tip that we published in our fall 2008 Service Detail newsletter. This exact problem came up recently and so I thought I would resurrect this tech tip for educational purposes. In the recent case we knew that the leakage current was very high and it had been several years since the deionizer cartridge was replaced. Replacing the deionizer cartridge was the logical solution. Replacing the cartridge did solve the problem for a while, but within a very short time the leakage current problem returned. Cleaning out the flow restrictor as described below solved the problem.

If you need replacement water filters or deionizer cartridges for your PHI 16-020 or 16-050 X-ray source heat exchangers that are available at this link – PHI Optics Parts

Deionizer flow restrictor inspection and cleaning procedure:

The 04-500 and 04-548 15kV dual anode x-ray sources are water cooled by a closed loop radiant heat exchanger (model 16-020, 16-050) which includes a built in water filter and deionizer cartridge. Since the anode floats at 15kV, the water must be kept in a constant state of deionization to prevent leakage current. If the leakage current is more than 2 or 3 mA at 15kV of high voltage then the leakage current will start to affect the power regulation on the 32-095 or 32-096 X-ray source control. Normal leakage current (the current that is shown on the HV supply current meter when only the high voltage and no power is applied) should be less than 2mA @ 15kV. Once you get up to 3 to 5mA it is time to replace the water filter and deionizer cartridge.  If the leakage is very high (10mA or more) then it is possible that the heat exchanger flow restrictor is plugged up.

Part of the loop in the cooling flow directs about 10% of the water through the deionizer and filter. There is a flow restrictor just in front of the input to the filter and this flow restrictor can become clogged or corroded over time, resulting in reduced flow to the deionizer cartridge and subsequent increased leakage current.

It is recommended that every time you replace the deionizer cartridge and filter (about once every 3 years is typical) that you inspect the flow restrictor and clean it out if necessary. If it is corroded you may need to drill it out with a tiny drill bit (about .030″).

The pictures below show the location of the flow restrictor and how to remove it for inspection. If it is plugged up then drill it out with a small drill bit and clean it before reinstalling it into the flow restrictor connector

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Heat exchanger preventive maintenance

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The 16-020 and 16-050 heat exchangers that are used with many Physical Electronics X-ray sources require a minimal amount of preventive maintenance to ensure that they provide sufficient cooling power.

Typically, the only maintenance that is performed is that the water filter and deionizer cartridge are replaced when the leakage current starts to creep up above 3-to-5mA. The deionizer cartridge helps to maintain the high resistivity of the distilled water that is circulated out to the x-ray source and back to the water tank via the radiator heat exchanger.

Note that the old 12″ Millipore housings that worked with the blue DI cartridges have a centering tab and that will push up on the new White deionizers. If you are replacing an original blue deionizer with the new white one, then you need to cut out the bottom of the original housing as otherwise the new deionizer can break and cause leakage of the mixed bed material into the water. Or, you can replace the 12″ original housing with new 12″ housing that is the correct size for the new deionizers. Contact RBD Instruments for more information about the 12″ deionizer and housing.

As shown in the pictures at the bottom of this post, one thing that is not obvious but should be checked once a year is the space between the cooling fan (in the 16-020) or fan blade (in the 16-050) and the radiator heat exchanger. Dust can collect on the fins of the heat exchanger radiator, which in turn can significantly reduce the cooling capacity of the heat exchanger.

Heat exchanger radiator cleaning procedure:

  1. Turn off the 32-095, 32-096, or 50-096 X-ray source control. This will ensure that the pump motor or air fan does not turn on.
  2. For the 16-050, trace the power cord back to the system and unplug it.
  3. Take the top cover off and remove the 4 screws that hold the cooling fan to the heat exchanger radiator. Unplug the fan power connector and set the fan aside.
  4. For the 16-020, turn the circuit breaker in the back of the unit to OFF.
  5. Remove the side panel to get better access to the heat exchanger radiator.
  6. Use a soft brush and a vacuum cleaner to remove any built-up dust from the heat exchanger radiator fins. If the fins have been bent from lack of care when removing the filter or deionizer cartridges, straighten the fins out with a small needle-nosed pliers or flat tweezers.
  7. For the 16-050, reinstall the fan. If the fan does not spin freely or makes a grinding noise when operated, it should be replaced as a preventive measure. Here is a link to a replacement fan: http://www.alliedelec.com/search/productdetail.aspx?SKU=70103674

Replacement parts for the heat exchanger (such as the deionizer and filter cartridges, flow switch and pump) are available from RBD Instruments at this link: Heat exchanger deionizer parts

Flow rate adjustment procedure:

If the pump has been replaced it needs to be adjusted to the proper flow rate. For the original Procon pumps you need to remove the acorn nut to get access to the adjustment screw. The new RBD replacement pumps do not have an acorn nut. Turn the screw CW to raise the flow rate and CCW to lower the flow rate.

There are 2 possible flow rates depending on which model of X-ray source(s) you have on your system.

If you have only the standard 04-500 or 04-548 15kV dual anode X-ray source, the flow rate should be set to 1.8 GPM.

If you have just the 10-550/560/610 mono source, the flow rate should be set to .9 GPM.

If you have both the standard 04-500/548 and a 10-550/560/610 mono source then the pressure should be set to .9 GPM.

Note that the flow rate is measured with the source(s) connected. The 16-050 has a built-in flow meter which makes this adjustment easy. In the case of the 16-020 (which does not have a flow meter), you need to either

1. Insert a flow meter in series for this adjustment
or
2. Simply disconnect the outlet of the last source in the string and drain the water into a clean bucket for 1 minute and then measure the amount of water that you collect. It is important to use a clean bucket so that you can reuse the water.

If you have leakage current problems with your source, we have found that draining all the water out of the heat exchanger and X-ray sources and replacing the water with distilled water from a grocery store will restore the water to the correct resistance. The deionizer cartridge (if it is still in good condition) will then maintain the water quality. To test for leakage current, increase the voltage on the X-ray source high voltage supply to 15kV with no power to the filaments and see what the leakage current is. Typically the leakage current should be less than 2mA if the deionizer is working properly. If the leakage current starts to get up to 3-to-5 mA then it is time to replace the deionizer cartridge. For mono sources it is recommended that the deionizer cartridge be replaced whenever the anode is replaced even if the leakage current is fine.

Keeping the heat exchanger radiator clean will help the X-ray source to run cooler, and that will extend the anode lifetime.

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