CHAPTER G 



MANIPULATING REVERSING THERMOMETER MALFUNCTIONS 



G-1 Introduction. — Reversing thermometers 

 may become malfunctional as a result of im- 

 proper handling, careless treatment, and/or 

 aging. In the laboratories where these instru- 

 ments are calibrated, malfunctions encountered 

 during the ordinary calibration procedures gen- 

 erally are manipulated if the malfunction is 

 coi-rectable. On ocean survey operations, how- 

 ever, when thermometers become malfunc- 

 tional, the number of instruments available for 

 taking ocean temperature measurements is pro- 

 portionately reduced, and action to relieve the 

 condition is often desirable and necessary. 

 Therefore, the following subjects are presented 

 to guide field personnel who may find it neces- 

 sary to manipulate malfunctional reversing 

 thermometers : 



Types of Reversing Thermometer Malfunc- 

 tions ; 



Corrective and Noncorrective Malfimctions; 



Equipment and Materials for Manipulating 

 Malfunctions; 



Detecting Malfunctions in a Reversing 

 Tliermometer ; 



Manipulating the FTD Type Malfunction 

 Aboard Ship ; 



Exercising Reversing Thermometers after 

 Manipulation. 



G-2 Types of Reversing Thermometer Mal- 

 functions. — When a revei'sing thermometer is 

 reversed or righted and the mercury in the in- 

 stiiiment does not separate or flow properly, the 

 reversing thermometer is malfunctional. Mal- 

 functions in reversing thennometers are classi- 

 fied as to type of improper mercury activity. 

 The following is a list of malfunctions which 

 may be encountered and the common abbrevia- 

 tion for the observed condition : 



Fails to Break (FTB) when reversed; 



Condition : Mercury does not run out of the 

 appendix or separate. 



Breaks below (BB) the appendix when re- 

 versed ; 



Condition: Mercuiy separates between the 

 appendix and bulb. 



Breaks above (BA) when reversed; 



Condition: Mercury separates between the 

 appendix and reservoir. 



Does not Run (DNR) when reversed; 



Condition: Mercury separates but fails to 

 rmi into bulb pi-operly. 



Fails to ReprodiK^e (FTR) when reversed; 



Condition: Stem reading not the same on 

 subsequent reversals at same tem- 

 perature or the same temperature 

 and pressure. 



Fails to Drain (FTD) when righted; 



Condition: Mercury does not empty out of 

 bulb properly when the ther- 

 mometer is righted. 



Floods (F) when reversed; 



Condition: Mercury runs out of reservoir 

 filling the bore completely. 



Mercury Sticks (HgS) in appendix when 

 reversed ; 



Condition: Mercury separates at or in the 

 appendix — all or a portion of the 

 mercury in the appendix does not 

 rim down. 



G-3 Corrective and Noncorrective Mal- 

 functions. — Disregarding economic considera- 

 tions, all malfunctions can be considered cor- 

 rectable. Corrective malfunctions in a practical 

 sense, however, are those which can be manipu- 

 lated without extensive laboratory equipment 

 and the skill of an experienced glassblower. 

 Noncorrective malfunctions are those which re- 

 sult from mistreatment, careless attempts to 

 manipulate corrective malfunctions, and aging. 

 Generally, no attempt is made to manipulate 

 the noncorrective malfunction. 



Corrective malfunctions essentially are 

 caused by the displacement of gas from the up- 

 per end of the bulb to other locations in the 

 thermometer system and the slight accumula- 

 tion of mercurial impurities at critical points 

 in the bore. These conditions arise as a result of 

 improper handling such as leaving the ther- 

 mometers inverted for imnecessarily long per- 

 iods of time at abnormal temperatures, expos- 

 ing them to shock while inverted, failing to 

 exercise the thermometers regularly, etc. 



Noncorrective malfunctions which result 

 from aging develop slowly as a result of mer- 

 curial deterioration and glass sizing which de- 

 forms the appendix or constriction. Signs of 

 the condition start to become evident about 1 

 year after the initial calibration tests have been 



G-1 



