US 9,810,377 B2
System and method for improving the accuracy of a rate of decay (ROD) measurement in a mass flow controller
Anthony Kehoe, Glenview, IL (US); John Lull, Glenview, IL (US); Bill Valentine, Glenview, IL (US); and Chris Ellec, Glenview, IL (US)
Assigned to Illinois Tool Works Inc., Glenview, IL (US)
Appl. No. 14/378,539
Filed by Illinois Tool Works Inc., Glenview, IL (US)
PCT Filed Mar. 4, 2013, PCT No. PCT/US2013/028897
§ 371(c)(1), (2) Date Aug. 13, 2014,
PCT Pub. No. WO2013/134136, PCT Pub. Date Sep. 12, 2013.
Claims priority of provisional application 61/608,000, filed on Mar. 7, 2012.
Prior Publication US 2015/0027558 A1, Jan. 29, 2015
Int. Cl. F17D 5/00 (2006.01); G01F 1/696 (2006.01); G01F 5/00 (2006.01); G01F 15/00 (2006.01); G05D 7/06 (2006.01)
CPC F17D 5/00 (2013.01) [G01F 1/6965 (2013.01); G01F 5/00 (2013.01); G01F 15/005 (2013.01); G05D 7/0635 (2013.01); Y10T 137/0402 (2015.04); Y10T 137/7784 (2015.04); Y10T 137/8175 (2015.04)] 17 Claims
OG exemplary drawing
 
12. A mass flow controller, comprising:
at least one conduit comprising a fluid inlet and a fluid outlet, the conduit defining a flow path along which the fluid flows;
an inlet block comprising an inlet passage, an inlet channel, and a reservoir fluidly coupled to the inlet channel upstream from a location at which the inlet channel is fluidly coupled to a bypass of the conduit, wherein the reservoir is configured, based on the operating conditions of the fluid, to facilitate a rate of decay measurement of the pressure of the fluid within the conduit while the mass flow controller is operational, and wherein the inlet block is formed from a single piece of material;
wherein filler material is disposed within the reservoir;
at least one pressure sensor that generates a pressure sensor signal that is indicative of the pressure of the fluid within the conduit, the at least one pressure sensor being coupled to a controller that is operable to generate a pressure sensor based pressure
measurement for the fluid, the pressure sensor based pressure measurement being determined at least in part from the pressure sensor signal;
at least one flow sensor that generates a flow sensor signal indicative of a flow rate of the fluid through the conduit, the at least one flow sensor being coupled to a controller that is operable to generate a flow sensor based flow rate for the fluid, the flow sensor based flow rate being determined at least in part from the flow sensor signal;
a control subsystem coupled to the at least one flow sensor; and
a valve assembly communicatively coupled to the control subsystem and operable to adjust the rate of fluid through the conduit.