NL2020230B1 - Portable viscometer and method of measuring a medium's viscosity - Google Patents

Abstract

Portable viscometer comprising a motor, an axle driv— en by the motor, and a body mounted on the axle which is ar— ranged for executing a turning motion in a medium of which a viscosity is to be measured, wherein a measuring organ is pro— vided for measuring a torque exerted by the motor on the medi— um, and a calculating organ is provided that is connected to the measuring organ for deriving the viscosity of the medium from the measured torque, wherein the body is equipped with at least two blades on opposite sides of the axle which lie in each other’s extended direction.

Description

Patent center

Θ 2020230

(2?) Application number: 2020230 (22) Application submitted: 3 January 2018

Int. Cl .:

G01N 11/14 (2018.01)

0 Application registered: 0 Patent holder (s): July 10, 2019 Delft University of Technology in Delft. 0 Request published: - 0 Inventor (s): Liu Xueyan in Delft. 0 Patent granted: Apostolidis Panos in Delft. July 10, 2019 Sandra Maria Johanna Grada Erkens in Delft. 0 Patent issued: July 10, 2019 0 Authorized representative: ir. J. van Breda et al. in Amsterdam.

54) Portable viscometer and method of measuring a medium's viscosity

Ξ) Portable viscometer including a motor, an axle driven by the motor, and a body mounted on the axle which is arranged for executing a turning motion in a medium or which a viscosity is to be measured, a measuring organ is provided for measuring a torque exerted by the motor on the medium, and a calculating organ is provided that is connected to the measuring organ for deriving the viscosity of the medium from the measured torque, the body is equipped with at least two blades on opposite sides of the axle which lie in each other's extended direction.

NL B1 2020230

This patent has been granted regardless of the attached result of the research into the state of the art and written opinion. The patent corresponds to the documents originally submitted.

Portable viscometer and method of measuring a medium's viscosity

The invention relates to a portable viscometer including a motor, a axle driven by the motor, and a body mounted on the axle which is arranged for executing a turning motion in a medium or which a viscosity is measured, is a measuring organ provided for measuring a torque provided by the motor on the medium, and a calculating organ is provided that is connected to the measuring organ for deriving the viscosity of the medium from at least the measured torque.

Such a portable viscera meter is known from for instance the Chinese utility models CN 202083610 and CN 2458618.

CN 202083610 discloses a portable type rotary viscometer. This known portable type rotary viscometer comprises a stepping motor, a torque sensor, a cylindrical probe, a function selecting key, a CPU (Central Processing Unit), a temperature sensor and an LCD (Liquid Crystal Display) screen, with the stepping motor rotates at a constant speed so as to drive the cylindrical probe to rotate, the cylindrical probe is used for producing torque in the direction reverse to the rotating direction. The torque is transferred to the torque sensor and is then transferred to the CPU after being processed by the torque sensor and the CPU is used to process the data of the torque sensor, with a viscosity value displayed on the LCD. The function selecting key is used for selecting a rotating speed of the stepping motor, and a signal of the temperature sensor is processed by the CPU for display on the LCD.

CN 2458618 relates to an electronic viscometer which is a portable and intelligent measuring instrument for the viscosity of liquids. This electronic viscometer measures the rotary speed of a sensor and the rheological and viscous resistance torque of the liquid are determined with a microcomputer by using the rotational shearing movement or a rotary torque sensor. The rheological and viscous resistance torque has changed into data which can be processed by the microprocessor through a signal processing circuit. Thereafter the in dexes of the viscosity of the liquids can be worked out through the microprocessor.

The portable viscometer or the prior art is not suitable for measuring the viscosity or granular mixes for constructional works as applied in civil engineering. Those granular mixes are different in nature in that they are essentially multiphase viscous mixtures as opposed to single phase viscous fluids that can be measured with the portable viscometer or the prior art.

It is therefore an object of the invention to provide a portable viscometer which is suited to measure the viscosity or a multiphase viscous mix as applied for constructional works.

It is another object of the invention to help practitioners to quickly determine the workability and functionality of the granular mixes utilized for those constructional works so as to be able to quickly determine the engineering characteristics of the mixes for the construction such as the optimum compaction time, compression strength and resistance to deformation under stress and thermal loads etc.

Not surprisingly, the invention is not only related to a portable viscometer but also to a method of determining the viscosity or a medium using such a viscometer.

The invention is embodied in a viscometer and in a method for measuring the viscosity of a medium in accordance with one or more of the appended claims.

In a first aspect of the invention the portable viscometer is provided with the feature that the body of the viscometer is equipped with at least two blades on opposite sides of the axle, which blades lie in each other's extended direction.

Best results are achieved when the body is equipped with four blades, each blade is at an angle of 90 ° with at least one other blade mounted on the axle.

Suitably each of the blades has the same length as seen in a longitudinal direction of the axle.

By using a body with blades instead of a smooth cylindrical head as known from the prior art, both the rheological and mechanical behavior or viscous granular mixes can be reliably determined. Because the blades have the same length, a uniform shear zone can be created inside the granular mix and hence a more accurate measurement of viscosity of the mix versus an instantaneously measured temperature and time can be obtained.

Preferably the granular mix is bound by a viscous binder selected from the group comprising bitumen, emulsions, thermoplastic and thermosetting polymer modified bitumen, cementitious paste.

By varying the rotation speed of the blades ^ of the viscometer, both dynamic viscosity and apparent viscosity of the multiphase viscous material of the medium, can be obtained.

It is preferred that a thermal sensor is attached to the viscometer to measure the in-situ material temperature or 15 the medium together with its viscosity at the same time. By correlating the rheological property of viscous binders tested in a lab and comparing it with the viscosity of the granular mixes measured by the viscometer of the invention, practitioners are enabled to determine quickly the workability and the 20 functionality of the granular mixes utilized in various engineering field activities.

The method for measuring a viscosity or medium including a multitude of particles, includes the provision of a body of the portable viscometer in the medium and rotating the 25 body in the medium with a first rotational speed and establishing a maximum radius Rc in which still shearing occurs in the medium, beyond beyond · maximum radius R _c no appreciable shearing occurs in the medium, and establishing the viscosity of the medium using the formula

ΠΛ · ?? ⁼ -------------------- in which T is the torque · that the motor applies to the medium via the blades of the viscometer ', Lm is the effective length of 35 the blades, Rm is the blade radius and Rc is the above-meant radius ^ or the effective shearing region, and rotation is the rotation speed of the blades of the viscometer.

It is preferred That establishment of the maximum radius R c Wherein still shearing Occurs in the medium is done by Relating it to a nominal maximum size of the particles in the medium, using the relation R _c = 15D _n Wherein D _n Denotes a nominal maximum size of the particles in the medium.

The invention will be further elucidated with reference to the drawing of an exemplary embodiment of an apparatus according to the invention that is not limiting as to the appended claims.

In the drawing:

-figure 1A and IB shows a viscometer according to the invention provided in a mix of which the viscosity must be measured, the device is shown in a cross-sectional side view and a cross-sectional top view respectively; and

-figure 2A and 2B shows a cross-sectional top view of the mix with a viscometer in operation, and showing respectively a shear stress and velocity profile distribution within the mix.

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

Turning now first to figure 1A and IB, it shows a portable viscometer 1 in operation, featuring the viscometer 1 comprising a motor 2, an axle 3 driven by the motor 2, and a body 4 mounted on the axle 3 which during operation executes a turning motion in a medium 5 or which a viscosity is measured. A measuring organ 6 is provided for measuring a torque exerted by the engine 2 that acts on the medium, and a calculating organ 7 is provided that is connected to the measuring organ 6 for deriving the viscosity of the medium 5 from the measured torque.

Further a speedometer 10 is shown to measure the rotational speed of the axle 3 on which the body 4 is mounted, as well as a thermal sensor 11 to measure the temperature of the medium 5. Both the speedometer 10 and the thermal sensor 11 are also connected to the calculating organ 7. A visual display unit 12 can for instance be connected to the calculating organ 7 to show the viscosity of the medium 5 that is calculated and based on the measurements of rotational speed and torque as exerted by the body 4 of the viscometer 1 on the med i um 5.

According to the invention the body 4 is equipped with at least two blades 8 ', 8' on opposite sides ^ or the axle: 3 which lie in each other's extended direction. This is best shown in figure 1B. _: Preferably the body 4 _: is equipped with four blades O ', c'',9', 9 '', each blade is at an angle of 90 ° with at least one other blade mounted on the axle 3, as- is also: shown in figure IB.

Figure 1A shows that each of the blades 8 ', 87 ^r , 9 ^r ,

9 ^'7 has the same length L _m as seen in a longitudinal direction of the: 3. The axle: minimum insertion depth of the viscometer 1 into the medium is, shown in Figure: 1A as the parameter H. With this parameter the Ή measured viscosity and temperature representative of the real status of the medium can be guaranteed. The recommended insertion depth H is 30 cm.

The · portable viscometer 1 of the invention can be effectively used in a method for measuring the viscosity of the medium 5 by providing the body 4 of the portable viscometer 1 in the: medium 5 and rotating the body 4 in the: medium 5 with a rotational speed and establishing a maximum radius Rc (see figure 1A) in which still shearing occurs in the medium: 5.

This maximum radius Rc in which still shearing occurs in the medium 5 must be understood within: the scope of the invention such that beyond the maximum radius Rc no appreciable · shearing occurs in the medium 5. The viscosity rjm of the medium can then 25 be determined using the formula

in which T is the applied torque as measured with the measur30 ing organ 6, L _m is the effective length of the stirrer (blade), Rm is the stirrer blade radius and Rc is the just mentioned radius of the effective shearing region, and ω is the rotation speed of the stirrer blades 8 ', S ^{r /} , & ^f _r S' ^s measured with the speedometer 10. To avoid misunderstanding it is remarked that within the scope of this application a speedometer is meant to measure a rotational speed or a rotating body, without need to apply any further functionality such as displaying this speed, although this is also not excluded from: the applica t ion,

It is possible to establish the maximum radius R _c still still shearing occurs in the medium 5 by estimating it visually. However, it is preferred to establish the maximum radius Re by related it to a nominal maximum size of the particles in the medium 5, using the relationship R _c = 15 Dan in D _a denotes a nominal maximum size of the particles in the medium 5 .

The device and method of the invention are particularly suitable for application on a medium 5 in the form of a granular mix bounded by a viscous binder selected from the group comprising bitumen, emulsions, thermoplastic and thermosetting polymer modified bitumen, cementitious · paste. These types of media are typically applied in civil engineering constructions,

The invention uses the principle that the torque relies quired to: turn the: viscometer blades θ ', θ'',9', 9 '' in the medium 5 is depending on the viscosity of the medium 5. The viscometer 1 measures the torque required to rotate the blades to, to ', to, to' in a multiphase medium consisting of granular particles bounded by viscous binders at a known applied rota20 tional speed m, the speed is measured with a speedometer 10 which measures the rotational speed of the axle 3, see Figs. 1A. The shear rate between the blades 8 ', 8', 9 ', 9 ^r "and the particles: of the medium: 5: Assumed constant at Any Given speed ω and, Thus, the viscosity can be calculated_PCR from 25 factors like stress and rate as discussed hereinafter. In particular, the shear stress in FIG. 2 (a) can be expressed as measured T is the applied torque as measured with the measuring organ S, and is the effective length of the blades · 8 ', 8'',9', 9 ''. It is further assumed that the shear force is perpendicular to its moment arm (r).

The viscosity p ™ or the multiphase medium 5 is assumed to follow Newton's fluid law and can be defined by dkl

T = —F! —— ^k Λ ar (2) is the velocity of the multiphase mix of the medium and the negative: sign in equation (2} indicates that · the: velocity decreases as r increases, r being the distance as measured from, a point in the medium: 5 to the center of the axis 3, see Fig. 2 (b) The velocity profile as shown in Fig. 2B is assumed to be linear The boundary conditions are given as -OK when its P _n is : the: radius of the blades 2 ', 2'',9', 9 '' (see figure IB), and ftc is the radius of the effective shearing interfered area as shown in figure 1A.

There are several ways in which: the maximum radius while still shearing occurs: in the medium: 5 can be deter20 mined, one of which is by visual observation. Other options are to: determine the maximum radius% by laboratory test or numerical simulation. Another simplified way of determining whether Re is to relate it to the nominal maximum size: On of particles in the medium 5. The preferred relationship to be used is then Ac = 15Dn, Wherein Da denotes the nominal maximum size of the particles in the medium .

From: the equations: (1) - (2) the viscosity of medium 5 is given as

(3) (4)

T Z 1 ί Λ 1; = 2 · η · £ J? / (5 30

and the viscosity of the multiphase medium 5 is given as

7 (¾.

(6) where ω is the rotation speed of the blades S ', 8 ⁷ ', 9 ', 9''or the: viscometer 1.

Example

For H = 0.3 m, 1 ^ = 0.15 m, Em = 0.11 m, E _e = 0.12 m, T = 0.4 Nm, ω = 2.0 rpm, the viscosity of the multiphase medium is 5

0.4 (8.12 - 0.1)

2 ^ (0.15) (2π ||) (0.1) ^, (0.12)

= 3.3 Fs s

Table 1 illustrates examples of using equation 6 by applying various levels of torque T with constant rotation speed & of the blades 8 ', 9'',9' ⁷ of the viscometer 1 in a medium or granular mixes which have: different maximum nominal particle sizes Dn.

TABLE 1. Viscosity output by applying various levels of torque in three different granular mixes:

(ΰ (rpm) Dn: (m) Re (m): RV> (HO L _n , (m): T (Nm) ηη ·, (Pa.s) 2Q 0.08 00 1.2 00 0.10 0.15 0.40 1.95 2 0 0.01 60 0.2: 40 0.10: 0.15 0.40: 1.24 2 0 0.0112 0.16: 8 0.10 0 :. 15 0.40 0.8 6 20 0.0800 1,200: 0.10 0.15 0.8 0 3.89 20 0.0112 0.240 0.10 0.15 0.80 2.48 20 0.0160 0.168 0.10 0.15 0.8 0 1: 12

Although the invention has been discussed in the foregoing with reference to an exemplary embodiment of the viscometer and method of the invention :, the invention is not restricted to: this particular embodiment which can be varied in many ways without departing from the invention. The dis25 cussed example is therefore not used to: construct the appended claims strictly in accordance with therewith. On the: contrary the embodiment is merely intended to explain the wording of the appended claims without: intent to limit: the claims to: this exemplary embodiment. The scope of protection of the invention shall therefore be constructed in accordance with the appended claims only, where possible ambiguity in the wording of the claims shall be resolved using this exemplary embodiment.

Claims (7)

CONCLUSIONS A portable viscosity meter (1) comprising a motor (2), a shaft (3) driven by the motor (2), and a body (4) mounted on the shaft (3) which is adapted to perform a rotational movement in a medium (5) of which a viscosity must be measured, wherein a measuring device (6) is provided for measuring a torque exerted by the motor (2) on the medium (5), and a calculating device (7) is provided which is connected to the measuring device (6) for deriving the viscosity of the medium (5) from at least the measured torque, characterized in that the body (4) is equipped with at least two blades (8½ 8 '', 9 ', 9' ') on opposite sides of the shaft (3) which are in line with each other. A portable viscosity meter according to claim 1, characterized in that the body (4) is equipped with four blades (8 ', 8' ', 9', 9 ''), each blade being at an angle of 90 ° with at least one other blade mounted on the shaft (3). Portable viscosity meter according to claim 1 or 2, characterized in that each of the blades (8 ', 8' ', 9', 9 '') has the same length as seen in a longitudinal direction of the shaft (3). A portable viscosity meter according to any one of claims 1-3, characterized in that a thermal sensor (11) is connected to the viscosity meter for measuring an in-situ temperature of the medium (5) during the measurement of the viscosity of said medium. Method for measuring a viscosity of a medium (5) comprising a plurality of particles, using a portable viscosity meter (1) according to one of claims 1-4, characterized by introducing a medium into the medium (5) the body (4) of the portable viscosity meter (1) and the rotation of the body (4) in the medium (5) at a rotation speed ω and determining a maximum radius Rc within which shear still takes place in the medium (5), and wherein no appreciable shear takes place in the medium (5) beyond the maximum radius R _c , and the determination of the viscosity f [m of the medium (5) using the formula T {in which T is the applied torque is that provided by the body (4) on the · medium (5), Lm the effective: length of: sheets (S ', 8'_'R9', 9 '') ·, Km is the radial length: of the blades (8 ', 8'',9', 9 ' ^f ), Kc is the radius of the effective shear area within the medium (5), and ω is the rotational speed of the blades : of the viscosity meter (1). A method according to claim 5, characterized by determining the maximum radius Re wherein shearing in the medium (5) still takes place by relating it to a nominal: maximum size of particles in the medium (5), using the relation Kc-15Dn where Dn represents a nominal maximum size of the particles in the medium: (5). Method according to claim 5 or 6, characterized by providing the medium (5) in the form of a: granular mix bound by a viscous binder selected from the group comprising bitumen, emulsions, thermoplastic and thermosetting polymer modified bitumen , cementitious pasta. 1/1 FIGURE 1A. C ross-seofcnai side v®w FIGURE 1. FIGURE 2A. Si-sear stress sfetrikfers FIGURE 2B. ¥ etó, 'leek is ctetrfejfei FIGURE 2.