초록 ▼

Metering and related control of fluid flow are achieved both accurately and at high response speed by way of a unique sequencing of thermal exchanges with the fluid under closely-regulated and inter-dependent thermal conditions. The flowing fluid is first conditioned by being raised to a temperature

Metering and related control of fluid flow are achieved both accurately and at high response speed by way of a unique sequencing of thermal exchanges with the fluid under closely-regulated and inter-dependent thermal conditions. The flowing fluid is first conditioned by being raised to a temperature above its highest anticipated ambient, preferably by way of a temperature-sensitive electrical heater resistance which is part of an exceptional self-balancing bridge and control-loop network, and the conditioned fluid is then similarly increased to yet higher temperature, with measurements related to energy involved in producing the second temperature increase being used to characterize the flow. When the fluid is at the same time further conditioned immediately downstream by another similar heating arrangement which allows the fluid to cool to between temperatures developed by the earlier sequencing, the measurements are rendered more stable and can advantageously be made more linearly proportional to mass flow rate. Additional isolation from ambient temperature disturbances is promoted by controlling the environment within which the sequencing of thermal exchanges takes place, preferably by way of a heated enclosure in which electrical regulation of temperature is also swift and exact.

대표청구항 ▼

Flowmeter apparatus comprising conditioning means for regulating the temperature of a flowing fluid by exchanging heat therewith in response to a supply of energy, thermal means disposed in heat-exchange relationship with the fluid regulated in temperature by said conditioning means for both exchang

Flowmeter apparatus comprising conditioning means for regulating the temperature of a flowing fluid by exchanging heat therewith in response to a supply of energy, thermal means disposed in heat-exchange relationship with the fluid regulated in temperature by said conditioning means for both exchanging heat with the fluid and for electrically characterizing temperature changes caused by flow of the fluid, control means responsive to temperature changes as characterized by said thermal means and supplying energy to said thermal means which changes the temperature of the fluid from the level of its regulated temperature to different values, thermal output conditioning means for regulating the temperature of the fluid immediately downstream of said thermal means to temperature between said level and the average of said different values, and flow measurement means characterizing energy supplied to at least one of said conditioning means and said thermal means, said control means supplying energy to said thermal means which maintains the said average of said different values of temperature substantially constant.