A tilting air-lubricated piston gage for pressures below one-half inch of mercury

Abstract

A desc t'ipt ion is given of a tilting dead-weight piston gage constructed at the National Bureau of Standards for ranges of differential pressure up to about 0.5 inch of mercury. A resolut ion of bett er than 1 part in a hundr ed t housand of fuJI scale has been obtained by use of the t oolmaker 's sine bar m ethod of angle measurernent. The scale is a lin ear function of t he sine. The instrument can be calibra tcd from basic measurem ents of length and weight, IS rugged , a nd m ay be constructed III almost any laboratory m echanical shop. Sources of possible errors in reading a re disc ussed in detail. Comparative t ests with certain other gages or manom eters ar e cited whe rein lin earity " 'as found to be wit hin 1 p art in 10 000 a nd a<rreem ent " 'ithin 2.5 parts in 10,000. The uses of the gage a re briefly disc ussed. ' 0