CN102564892B - Method for measuring pressure drop reduction value of draw resistance standard rod and method for detecting reasonability of design of suction pipeline of draw resistance tester by using value - Google Patents

Abstract

The invention relates to the field of the measurement of draw resistance (or pressure drop) of cigarettes, and in particular relates to a method for measuring a pressure drop reduction value of a draw resistance standard rod and a method for detecting the reasonability of the design of a suction pipeline of a draw resistance tester by using the value. The invention provides a method for measuring the flow of an output end of the draw resistance standard rod and the pressure drop reduction value of the draw resistance standard rod. According to the method, two judging parameters, namely the pressure drop reduction value delta P' of the draw resistance standard rod and the flow V1 of the output end of the draw resistance standard rod can be conveniently calculated by establishing a relational model of the pressure drop reduction value delta P' of the draw resistance standard rod, the flow V1 of the output end of the draw resistance standard rod and the pressure drop of two ends of the draw resistance standard rod; and the method has the characteristics of convenience for detection and calculation.

Description

Whether reasonably the measuring method of resistance to suction master bar pressure drop reduction value and this value for detecting resistance absorbing instrument aspiration design method

Technical field

The present invention relates to the fields of measurement of Cigarette Draw Resistance (or pressure drop), particularly relating to a kind of measuring method of resistance to suction master bar pressure drop reduction value and this value for detecting resistance absorbing instrument aspiration design whether reasonably method.

Background technology

Cigarette Draw Resistance and filter stick pressure drop are the important parameters of cigarette filter rod physical index, for ensureing its measurement accuracy, resistance to suction master bar need be adopted to calibrate resistance absorbing instrument.At present, each resistance absorbing instrument all adopts standard constant current hole and CFO (Critical Flow Orifice) as its constant current generating means to produce the air-flow of 17.5mL/s.In instrument calibration process, owing to there is the damping element such as solenoid valve, filtrator in aspiration, cause pressure drop pipeline producing a certain size, the difference of this voltage drop value can affect the gas flow of resistance to suction master bar output terminal, and then affects the resistance to suction value of resistance to suction master bar.At present, one is not also had well can be used in detection resistance absorbing instrument aspiration design whether reasonably method.

Summary of the invention

In order to solve above-mentioned technical matters, an object of the present invention is to provide the measuring method of resistance to suction master bar output terminal flow and resistance to suction master bar pressure drop reduction value, whether reasonably another object of the present invention is to provide a kind of for detecting resistance absorbing instrument aspiration design method, the method has easy to detect, calculates easy feature.

In order to realize above-mentioned first object, present invention employs following technical scheme:

The measuring method of resistance to suction master bar output terminal flow and resistance to suction master bar pressure drop reduction value, the method comprises the following steps:

1) pipeline of resistance to suction master bar calibration instrument comprises negative pressure generator, detection head, CFO and aspiration, and detection head, aspiration, CFO are connected successively with negative pressure generator, and master bar output terminal is A, CFO inlet end is B, B place flow Q ₂keep 17.5ml/s constant, atmospheric pressure is P _atm, aspiration pressure drop is Δ P, and the pressure drop recording master bar two ends is P ₁, namely master bar resistance to suction is P ₁;

2) gas is held to meet equation of gas state PV=nRT for A, B

Consider that gas is Steady Flow at this, volume flow Q be the volume V that flows through in same equal time divided by time t, consider that both sides are with divided by the time, have

(P _atm-P ₁)V ₁/t＝(P _atm-P ₁-ΔP)V ₂/t (1)

Have

$V_1=\frac{P_{\mathrm{atm}}-P_1-\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1}{V}_2=(1-\frac{\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1})V_2---\left(2\right)$

Known at P _atmwhen constant with P, aspiration pressure drop is larger, flows through master bar output terminal volumetric flow rate less, V ₁/ t is resistance to suction master bar output terminal flow, i.e. Q ₁, V ₂/ t is CFO inlet end flow, i.e. Q ₂;

2) for same resistance to suction master bar, its pressure drop meets Ha Gen-poiseuille theorem, and namely master bar resistance to suction is directly proportional to output terminal flow, has

$\frac{P_1}{P^{\′}}=\frac{V_1}{17.5}=\frac{V_1}{V_2}---\left(3\right)$

Then when there being aspiration pressure drop to cause actual flow to diminish, the resistance to suction P of master bar ₁have

$\frac{P_1}{P^{\′}}=1-\frac{\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1}---\left(4\right)$

Solve:

$P_1=\frac{P_{\mathrm{atm}}+P^{\′}-\sqrt{{(P_{\mathrm{atm}}-P^{\′})}^2+4P^{\′}\mathrm{\ΔP}}}{2}---\left(5\right)$

And the pressure drop reduction value Δ P ' of master bar under 17.5ml/s flow and actual flow is

$\mathrm{\Δ}{P}^{\′}{=P^{\′}-P}_1=\frac{P^{\′}{-P}_{\mathrm{atm}}+\sqrt{{(P_{\mathrm{atm}}-P^{\′})}^2+4P^{\′}\mathrm{\ΔP}}}{2}---\left(6\right).$

In order to realize above-mentioned second object, present invention employs following technical scheme:

Whether reasonably for detecting resistance absorbing instrument aspiration design method, the method comprises the following steps:

1) resistance to suction master bar output terminal flow V is calculated by described method ₁the resistance to suction master bar output terminal flow V that/t and resistance to suction master bar pressure drop reduction value Δ P ' is described ₁/ t computing formula is as follows:

$V_1=\frac{P_{\mathrm{atm}}-P_1-\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1}{V}_2=(1-\frac{\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1})V_2;$

Resistance to suction master bar pressure drop reduction value Δ P ' computing formula is as follows:

$\mathrm{\Δ}{P}^{\′}{=P^{\′}-P}_1=\frac{P^{\′}{-P}_{\mathrm{atm}}+\sqrt{{(P_{\mathrm{atm}}-P^{\′})}^2+4P^{\′}\mathrm{\ΔP}}}{2};$

Above-mentioned P1 is the actual pressure differential at resistance to suction master bar two ends, and the computing formula of P1 is as follows:

$P_1=\frac{P_{\mathrm{atm}}+P^{\′}-\sqrt{{(P_{\mathrm{atm}}-P^{\′})}^2+4P^{\′}\mathrm{\ΔP}}}{2};$

Above-mentioned V ₁/ t is resistance to suction master bar output terminal flow; Δ P ' is resistance to suction master bar pressure drop reduction value; V ₂/ t is CFO inlet end flow, is worth for 17.5ml/s; Δ P is the actual aspiration pressure drop recorded, and P is the resistance to suction value that resistance to suction master bar records under 17.5ml/s flow; Pa is atmospheric pressure;

2) by resistance to suction master bar output terminal flow V ₁/ t and the acceptable deviate of resistance to suction master bar pressure drop reduction value Δ P ' judge whether aspiration design is reasonable.

The present invention by above-mentioned technical scheme, by setting up resistance to suction master bar pressure drop reduction value Δ P ' and resistance to suction master bar output terminal flow V ₁the relational model of/t and two ends pressure drop, can calculate resistance to suction master bar pressure drop reduction value Δ P ' and resistance to suction master bar output terminal flow V easily ₁/ t these two judges parameter foundation, has easy to detect, calculates easy feature.

Accompanying drawing explanation

Pipeline schematic diagram when Fig. 1 is resistance to suction master bar calibration instrument.

Embodiment

Pipeline schematic diagram during resistance to suction master bar calibration instrument as shown in Figure 1, comprises negative pressure generator 1, detection head 2, CFO device 3 and aspiration 4, due to CFO inlet end B place flow Q in pipeline ₂keep 17.5ml/s constant, aspiration pressure drop is to the flow Q at master bar output terminals A place ₁impact analysis as follows:

Suppose that atmospheric pressure is Pa, aspiration pressure drop is Δ P, and the pressure drop at master bar two ends is P ₁(due to now V ₁no longer 17.5ml/s, P ₁also be no longer the nominal value of master bar).

1) gas is held to meet equation of gas state PV=nRT for A, B

Consider that gas is Steady Flow at this, volume flow Q be the volume V that flows through in same equal time divided by time t, consider that both sides are with divided by the time, have

(P _atm-P ₁)V ₁/t＝(P _atm-P ₁-ΔP)V ₂/t (1)

Have

$V_1=\frac{P_{\mathrm{atm}}-P_1-\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1}{V}_2=(1-\frac{\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1})V_2---\left(2\right)$

Known at P _atmwhen constant with P, aspiration pressure drop is larger, flows through master bar output terminal volumetric flow rate less.

2) for same resistance to suction master bar, its pressure drop meets Ha Gen-poiseuille theorem, and namely master bar resistance to suction is directly proportional to output terminal flow, has

$\frac{P_1}{P^{\′}}=\frac{V_1}{17.5}=\frac{V_1}{V_2}---\left(3\right)$

Then when there being aspiration pressure drop to cause actual flow to diminish, the resistance to suction P of master bar ₁have

$\frac{P_1}{P^{\′}}=1-\frac{\mathrm{\ΔP}}{P_{\mathrm{atm}}-P_1}---\left(4\right)$

Solve:

$P_1=\frac{P_{\mathrm{atm}}+P^{\′}-\sqrt{{(P_{\mathrm{atm}}-P^{\′})}^2+4P^{\′}\mathrm{\ΔP}}}{2}---\left(5\right)$

And the pressure drop reduction value Δ P ' of master bar under 17.5ml/s flow and actual flow is

$\mathrm{\Δ}{P}^{\′}{=P^{\′}-P}_1=\frac{P^{\′}{-P}_{\mathrm{atm}}+\sqrt{{(P_{\mathrm{atm}}-P^{\′})}^2+4P^{\′}\mathrm{\ΔP}}}{2}---\left(6\right)$

The present invention is by above-mentioned technical scheme, and calculate according to formula (2) and (6), result as shown in Table 1 and Table 2.As can be seen from Table 1, aspiration pressure drop is larger, and resistance to suction master bar output terminal flow is less; As can be seen from Table 2, aspiration pressure drop is larger, and the resistance to suction value difference of same sample is different larger.By setting resistance to suction master bar pressure drop reduction value Δ P ' and resistance to suction master bar output terminal flow V ₁whether reasonable the acceptable deviate of/t, can judge to detect the design of resistance absorbing instrument aspiration.

Claims (2)

1. the measuring method of resistance to suction master bar output terminal flow and resistance to suction master bar pressure drop reduction value, is characterized in that the method comprises the following steps:

1) pipeline of resistance to suction master bar calibration instrument comprises negative pressure generator, detection head, CFO and aspiration, and detection head, aspiration, CFO are connected successively with negative pressure generator, and master bar output terminal is A, CFO inlet end is B, B place flow Q ₂keep 17.5ml/s constant, atmospheric pressure is P _atm, aspiration pressure drop is Δ P, and the pressure drop recording master bar two ends is P ₁, namely master bar resistance to suction is P ₁;

2) gas is held to meet the equation of gas state for A, B

Consider that gas is Steady Flow at this, volumetric flow rate qit is the volume flow through in same equal time vdivided by the time t, consider that both sides are with divided by the time, have

(1)

Have

(2)

Known p _atmwith p ₁when constant, aspiration pressure drop is larger, flows through master bar output terminal volumetric flow rate less, V ₁/ t is resistance to suction master bar output terminal flow, i.e. Q ₁, V ₂/ t is CFO inlet end flow, i.e. Q ₂;

3) for same resistance to suction master bar, its pressure drop meets Ha Gen-poiseuille theorem, and namely master bar resistance to suction is directly proportional to output terminal flow, has

(3)

Then when there being aspiration pressure drop to cause actual flow to diminish, the resistance to suction of master bar p ₁have

(4)

Solve:

(5)

And the pressure drop reduction value Δ of master bar under 17.5ml/s flow and actual flow p' be

(6)；

p 'for the resistance to suction value that resistance to suction master bar records under 17.5ml/s flow.

2., for detecting resistance absorbing instrument aspiration design whether reasonably method, it is characterized in that the method comprises the following steps:

1) resistance to suction master bar output terminal flow V is calculated by method according to claim 1 ₁/ t and resistance to suction master bar pressure drop reduction value Δ P 'described resistance to suction master bar output terminal flow V ₁/ t computing formula is as follows:

；

Resistance to suction master bar pressure drop reduction value Δ P 'computing formula is as follows:

；

Above-mentioned p ₁for the actual pressure differential at resistance to suction master bar two ends, p ₁computing formula as follows:

；

Above-mentioned v ₁/ t is resistance to suction master bar output terminal flow; Δ p' be resistance to suction master bar pressure drop reduction value; v ₂/ t is CFO inlet end flow, is worth for 17.5ml/s; Δ pfor the actual aspiration pressure drop recorded, p 'for the resistance to suction value that resistance to suction master bar records under 17.5ml/s flow; p _atmfor atmospheric pressure;

2) judge whether aspiration design is reasonable by resistance to suction master bar output terminal flow V1/t and the acceptable deviate of resistance to suction master bar pressure drop reduction value Δ P '.