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Method for determining CMF (constant mass flow) pressure drop by adopting CFO (critical flow orifice) device and method for establishing model for CMF pressure drop determination

A technology for establishing methods and conversion models, applied in the direction of analyzing materials, instruments, etc., can solve problems such as no theoretical basis

Active Publication Date: 2012-06-27
CHINA TOBACCO ZHEJIANG IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The above conversion formula is only an empirical formula and has no theoretical basis

Method used

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  • Method for determining CMF (constant mass flow) pressure drop by adopting CFO (critical flow orifice) device and method for establishing model for CMF pressure drop determination
  • Method for determining CMF (constant mass flow) pressure drop by adopting CFO (critical flow orifice) device and method for establishing model for CMF pressure drop determination
  • Method for determining CMF (constant mass flow) pressure drop by adopting CFO (critical flow orifice) device and method for establishing model for CMF pressure drop determination

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Embodiment Construction

[0064] A method for establishing a conversion model between the suction resistance and pressure drop values ​​measured by the CFO device and the CMF device, the method comprising the following steps:

[0065] Assume that the pressures at both ends of the sample (cigarette and filter rod) are P in and P out , and the volume flows are Q in and Q out , for actual measurements P in is equal to the atmospheric pressure, that is, P in =P a (P a to atmospheric pressure).

[0066] From the ideal gas equation of state

[0067]PV = nRT (3)

[0068] At both ends of the sample there are

[0069] P a Q in =P out Q out =(P a -P)Q out (4)

[0070] In the formula, P is the sample pressure difference (drawing resistance).

[0071] ∂ ( PQ ) ∂ z = P ∂ Q ...

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Abstract

The invention relates to the cigarette draw resistance (or pressure drop) measuring field, and especially relates to a method for determining the CMF pressure drop by adopting a CFO device and a method for establishing a model for the CMF pressure drop determination. According to the invention, the method for determining the CMF pressure drop by adopting the CFO device and the method for establishing the model for the CMF pressure drop determination are disclosed, theoretical models of a CFO draw resistance measure method and the CMF draw resistance measure method are detailedly introduced and analyzed, and a case that a derived formula is closer to a table transition relation than a formula in an ISO6565 table is obtained by comparing the formula which is used for the transition between the CFO method and the CMF method and is obtained by deriving through the theoretical models with the formula in the ISO6565 table.

Description

technical field [0001] The invention relates to the field of measurement of cigarette draw resistance (or pressure drop), in particular to a method for measuring CMF pressure drop using a CFO device and a method for establishing the model. Background technique [0002] There are currently two types of instruments used for the measurement of resistance to draw (or pressure drop). The two vacuum-operated instruments are described below: The first type is called critical orifice flow (CFO), ie a device with a constant volumetric flow. The instrument always maintains a constant volume flow at the output end of the test object regardless of the air pressure. As the pressure drop of the test object increases, the flow rate at the input end will decrease. Thus, the mass flow rate decreases as the pressure drop of the test substance increases. [0003] The second type is called constant mass flow (CMF), a device that maintains a constant mass flow rate of air through all test items...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N7/10
Inventor 蒋志才苏中地赵航丁雪方婷黄华韩彬张勍苗芊杨荣超尹招琴朱强
Owner CHINA TOBACCO ZHEJIANG IND