Mass flow meter

• US 20080016957A1
• Filed: 06/26/2007
• Published: 01/24/2008
• Est. Priority Date: 07/21/2006
• Status: Abandoned Application

• Current Assignee: MKS Japan, Inc. (MKS Instruments Incorporated)
• Original Assignee: MKS Japan, Inc. (MKS Instruments Incorporated)
• Inventors: Suzuki, Isao
• Application Number:
  US11/819,244
• Publication Number:
  US 20080016957A1
• Time in Patent Office: Days
• US Class Current: 73/204.21
• CPC Class Codes: G01F 1/6842 with means for influencing the fluid flow
• CPC Class Codes: G01F 1/6847 where sensing or heating elements are not disturbing the fluid flow, e.g. elements mounted outside the flow duct
• CPC Class Codes: G01F 15/00 Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
• CPC Class Codes: G01F 5/00 Measuring a proportion of the volume flow
• CPC Class Codes: G01F 7/00 Volume-flow measuring devices with two or more measuring ranges; Compound meters

Abstract

A mass flow meter has a range of flow rate measurement that can be enlarged by changing of the structure of a sensor portion without modification of a bypass portion. The mass flow meter includes a sensor tube 5 through which fluid is transmitted while being heated, the flow meter being adapted to detect a mass flow rate of the fluid, based on a change in temperature distribution in the narrow sensor tube 5 that occurs according to the mass flow rate of the fluid, the flow meter comprising a flow restriction channel 7 for the fluid that is disposed in series with the narrow sensor tube 5.

Claims

1. A mass flow meter including a sensor tube through which fluid is transmitted while being heated, the flow meter being adapted to detect a mass flow rate of the fluid, based on a change in temperature distribution in the narrow sensor tube that occurs according to the mass flow rate of the fluid, the flow meter comprising at least

a flow restriction channel for the fluid that is disposed in series with the sensor tube.

2. A mass flow meter according to claim 1, wherein the flow restriction channel is selectable from a plurality of flow restriction channels each having a different fluid conductance.

3. A mass flow meter including a sensor tube through which fluid is transmitted while being heated, the flow meter being adapted to detect a mass flow rate of the fluid, based on a change in temperature distribution in the sensor tube that occurs according to the mass flow rate of the fluid, the flow meter comprising at least

a flow restriction channel for the fluid disposed in series with the sensor tube and,

a fluid bypass portion for the fluid disposed in parallel with the sensor tube.

4. A mass flow meter according to claim 3, wherein the flow restriction channel is selectable from a plurality of flow restriction channels each having a different fluid conductance.

5. A mass flow meter according to claim 3, a flow restriction channel is provided in a part of the fluid bypass portion.

6. A mass flow meter according to claim 3, further comprising at least a sensor bypass channel that makes a fluid bypass between both edges of the sensor tube.

7. A mass flow meter including a sensor tube through which fluid is transmitted while being heated, the flow meter being adapted to detect a mass flow rate of the fluid, based on a change in temperature distribution in the sensor tube that occurs according to the mass flow rate of the fluid, the flow meter comprising at least

a flow restriction channel for the fluid disposed in series with the sensor tube and,

a selectable fluid bypass portion, disposed in parallel with the sensor tube, in a part of which the flow restriction channel is structured.

8. A mass flow meter according to claim 7, further comprising at least a sensor bypass channel, that makes a fluid bypass between both edges of the sensor tube, which is structured in a part of the selectable fluid bypass portion.