No.4 Business Building-2707, China Central Place
Chaoyang District, Beijing-100021, China
Email:[email protected]
北 京 大 林 绿 源 环 保 科 技 有 限 公 司
BEIJING DAELIM GREEN EP TECH CO., LTD.
5.6 Pressure VacuumGauge
The pressure vacuum gauge (Fig. 8) indicates whether the head space pressure inside the tank is positive,
negativeorneutral.Thepressureinsidethetankwillvarydependingontheloadoftheunit,temperatureof
the oil and ambient temperature outside. As the oil temperature rises, the pressure inside the tank also rises.
Asthetemperaturefalls,thepressurefalls.Itiscommonforatransformertohaveeitherapositivepressure
or a negativepressure.
Do not be alarmed by a consistent negative pressure (for example, if it’s winter time
In Wisconsin, it will probably be negative for the duration of the season). However, if the gauge consistently
readszero anddoesnotappeartobe changingwith environmental orloadconditions,thismaybean
indication of a leak and may need attention. Visually inspect the unit for any signs of a leak or damaged seal.
The pressure/vacuum gauge can also be equipped with SPDT alarm contacts (by adding a separate pressure
alarm switch) for remote monitoring of positive and negative pressures. When requested, the
pressure/vacuumgaugecanalsobeequippedwithableederorregulator;whenusedinconjunctionwithan
externalnitrogensupply,positivepressurecanbemaintainedinsidethetank(2.5to3.0PSI)Theregulatoris
also equipped with a fitting and valve to take gas samples.
Fig. 8