Fluid property sensor with heat loss compensation and operating method thereof

摘要

An improved Pirani sensor uses a measuring element disposed within a fluid between a base plate and a cover. The measuring element is held by suspension members that are connected to the base plate. A heating element is thermally conductively connected to the suspension members. Using the sensor the characteristic of the fluid is determined by evaluating the heat transfer from the thermal element through the fluid into the cover when heating power is applied to measuring element. Parasitic conductive heat loss from the measuring element into the suspension members is compensated by applying power to the heating element.

主权项

1. A thermal conductivity sensor for measuring a characteristic of a fluid, comprising:
a measuring element disposed within the fluid adjacent to a heat sink, the measuring element being held by suspension members; one or more suspension heating elements thermally conductively connected to the suspension members; and a control processor operatively connected to the measuring element and to the one or more suspension heating elements, wherein the one or more suspension heating elements are operatively connected to a suspension temperature controller, and wherein the control processor applies power to the one or more suspension heating elements to maintain a substantially constant temperature T1, and wherein the control processor applies pulsed power to the measuring element until the measuring element reaches a predetermined temperature T2.