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Monarch F80 Spray Nozzles used in all Xenon Arc Instruments
At some point the Monarch changed the design of their spray nozzles from a formed hole to a straight drilled hole. The new style nozzles do not operate as efficiently as the old and require higher DI water pressures to generate a nice conical pattern that gives good sample coverage. If the instrument's "user guide" is followed the specification for DI water pressure is 18 to 20 psi. With the earlier style nozzles this was enough to give good pattern, with the new style nozzles they really don't even start spraying well until 25 psi to 27 psi, working their best at 30-32 psi.
Increasing the spray pressure to maintain the nozzle pattern will probably increase errosion and time of wetness. This is a trade-off since a poor pattern results in insufficient coverage.
You should also run a coverage check on the samples. The spray headers on many Ci65A's from about CB-2000 and later are hanging down very low. In one case the center nozzle was only 3/4" from the bottom of the sample. A photo below shows a mild example of misalignment. There is a limited adjustment on top, but I have found that setting the adjustment to the middle and cutting the tubing to obtain the correct height works best.
I'm trying to find a suitable type of paper to run a coverage check. By installing a (for example,) dark colored construction paper and allow the paper to pass through the spray once, you should get an idea of coverage. I was clogging the top nozzle to prevent drippage from influencing the pattern on the paper.
The OEM manual suggests a toothpic to clean the nozzle. I've found disassembling the nozzle and cleaning the insert and inside of the nozzle is also required.
