Tom,

GOOD NEWS: WE’VE REPLACED THE BS-II FRIT
Here are the events leading to the malfunction.

HETP RESULTS OK BEFORE COLUMN PROBLEMS
Original lab test showed

• HETP at 0.05 cm/plate
• 198 plates.

This amount was acceptable.

SUBSEQUENT TESTS FAILED: WE DETECTED TRAPPED AIR
Between regeneration and WFI rinse, air was accidentally pumped into the headspace. This area is between the top frit and the resin bed. An HETP test revealed unacceptable results: fewer than 100 plates.

We tried to displace the air by pumping WFI up through the column. Most of the air was pushed through the top column tube. We repacked the column with WFI. HETP tests were again unacceptable so we retried the procedure.

DISCOVERY OF KEY PROBLEM
While pumping WFI through the column a second time I detected

• resin flowing into tubing at column inlet
• top frit mesh torn away from support piece.

Because of the break, resin was passing by the top frit. Refer to the frit diagram I placed in your mailbox.

ACTIONS TAKEN
I took the following steps:

1. replaced the top frit
2. reslurried the resin
3. repacked the column
4. ran an HETP test.

The results of the test were good: HETP=0.043 and 230 plates.

CURRENT STATUS
The bottom frit is intact and no resin has been lost. The column has been regenerated and stored; it is ready for use in the next batch.

Notes

Key message in the subject line

The bottom line is in the subject line so the reader immediately knows what the message is about.

Positive approach

Rather than focusing on the problem up front, the writer explains that it has been fixed. After reading that at the beginning, the reader will be more receptive to the message.

Logical sequencing

It’s easy for the reader to follow the chronologically sequenced events leading to the solution.

Clear, concise explanation

Shorter sentences and clearly defined terms ensure that even a nontechnical reader could understand what happened.

Bullets and white space to guide the reader

Headlines, bullets, and white space all help important points stand out so the reader can find information quickly and easily. Dense text is much more difficult to read.

Action words

Using strong verbs energizes the message and helps the writer clearly explain how he fixed the problem.

Numbers to show the sequence of events

Numbering the events ensures that the reader understands the process and that it could be duplicated in the future if necessary.

Informative headlines

The reader wants to know what happened and what’s been done about it. The headlines guide the reader to find answers easily and contribute to the logical flow of information.