A method of measuring airflow from an HVAC outlet vent using a volume fill airflow measurement device having a LIDAR or Time-of-Flight (ToF) laser-ranging sensor to detect a filled state of a volume capture element or bag, comprising placing a frame having the bag sealably attached thereto over the vent to be measured, starting a timer, stopping the timer automatically in response to the LIDAR or Time-of-Flight (ToF) laser-ranging sensor measuring the distance to be within a predetermined range, and calculating the measured airflow based on the volume of the bag and the time for the airflow to fill the bag. The measured airflow is then displayed on the device display.

A reference volume for use with pressure change flow rate measurement apparatus has an internal structure comprising elements with cross section and length comparable to the cross section and length of adjacent interstitial fluid regions. The reference volume may have one or more heat conduction elements exterior to and in good thermal contact with a corrosion resistant material that defines the internal fluid holding region.

An electronic device manufacturing system includes: a gas supply; a mass flow controller (MFC) coupled to the gas supply; an inlet coupled to the MFC; an outlet; a control volume serially coupled to the inlet to receive a gas flow; and a flow restrictor serially coupled to the control volume and the outlet. A controller is adapted to allow the gas supply to flow gas through the control volume and the flow restrictor to achieve a stable pressure in the control volume, terminate the gas flow from the gas supply, and measure a rate of pressure decay in the control volume over time. A process chamber is coupled to a flow path, which is coupled to the mass flow controller, the process chamber to receive one or more process chemistries via the mass flow controller.

Methods and systems for determining a base field prover volume of a field prover include connecting together a transfer meter assembly, a master prover, and the field prover in series. A flow of fluid at a first flow rate is provided and a calibration sequence is performed at the flow rate. The calibration sequence includes counting pulses generated by the transfer meter assembly over a duration of each pass of the master prover and a pass of the field prover. An intermediate calibrated field prover volume is determined from a ratio of the field prover pulse count to the average master prover pulse count, multiplied by a base master prover volume. The calibration sequence can be repeated to provide at least three intermediate calibrated field prover volumes at the first flow rate. The calibration sequence can be repeated at different flow rates to arrive at the base field prover volume.

A valve of a first container is opened to remove fluid into a second container, where the output of the first container is above a maximum fluid level of the second container. The valve of the first container is closed based on a sensor indicating that a fluid level in the first container is at a first fluid level. A pump pumps the fluid from the second container to the first container via a flow meter. An indication is received that causes the pump to stop pumping based on the indication. An amount of fluid pumped into the first container is determined based on the first fluid level and a second fluid level indicated by the sensor. An indication of total fluid volume measured by the flow meter is compared to the amount of fluid pumped. An indication of accuracy of the flow meter is output based on the comparison.

A reference volume for use with pressure change flow rate measurement apparatus has an internal structure comprising elements with cross section and length comparable to the cross section and length of adjacent interstitial fluid regions. The reference volume may have one or more heat conduction elements exterior to and in good thermal contact with a corrosion resistant material that defines the internal fluid holding region.

Mass flow verification systems and apparatus verify mass flow rates of mass flow controllers (MFCs) based on pressure decay principles. Embodiments include a location for coupling a calibrated gas flow standard or a MFC to be tested in a line to receive a gas flow from a gas supply; a control volume serially coupled to the location in the line to receive the gas flow; a flow restrictor serially coupled to the control volume; a pump serially coupled to the flow restrictor; and a controller adapted to allow the gas supply to flow gas through the mass flow control verification system to achieve a stable pressure in the control volume, terminate the gas flow from the gas supply, and measure a rate of pressure decay in the control volume over time. Numerous additional aspects are disclosed.

Provided are systems and methods for line volume calibration, and measurement of fluid samples delivered to an interrogation point. In various embodiments, a known fluid volume comprising a sample line fluid and a secondary fluid is delivered to a fluid boundary sensor. The fluid boundary sensor assists in determining the position of the boundaries between the various fluids, and the positions of these boundaries are used to determine the sample line fluid volume.

A method includes determining a rotational position of a crankshaft in a multiplex pump from one or more sensors disposed on the crankshaft, determining a position of each of a plurality of pistons along a corresponding pump bore in relation to a total stroke length of each piston and a connecting rod length, calculating an individual theoretical displaced volume of fluid for each of the pump bores in the multiplex pump based on the rotational position of the crankshaft, and summing the individual theoretical displaced volumes to determine a total theoretical pumped volume by the multiplex pump. A calibration method includes determination of the multiplex pump efficiency versus speed and discharge pressure, and the effect of pump leakage and valve closing delay on the pump efficiency. Verification of the pump performance and efficiency may be controlled during pumping to insure the validity of the last calibration data set.

Disclosed are mass flow controllers, apparatuses for manufacturing semiconductor devices, and methods of maintenance thereof. The mass flow controller may control an amount of a gas provided into a chamber. The mass flow controller may be configured to obtain an absolute volume of the gas provided into the chamber at a standard flow rate when the mass flow controller is initially used. The mass flow controller may be configured to obtain a detected flow rate of the gas provided at a measured flow rate after the mass flow controller has been used for a predetermined time. The mass flow controller may be configured to compare the detected flow rate and the standard flow rate to verify a full-scale error in the measured flow rate.