WO2003047759A1

WO2003047759A1 - Modular centrifuge

Info

Publication number: WO2003047759A1
Application number: PCT/GB2002/005537
Authority: WO
Inventors: Neil Baker
Original assignee: Neil Baker
Priority date: 2001-12-05
Filing date: 2002-12-05
Publication date: 2003-06-12
Also published as: GB0129062D0; AU2002347361A1

Abstract

The present invention relates to an adaptable modular centrifuge that can facilitate either a drum ring channel or a beam rotor. In all cases, there is a removable test environment and a securing means, such that the main body of the centrifuge can be used with different test environments, depending on the requirements of the user.

Description

Modular Centrifuge

The present invention relates to a Centrifuge and in particular to an adaptable modular Centrifuge that can facilitate either a Drum Ring Channel or a Beam Rotor.

The construction and use of compact Geotechnical Centrifuge (CGC) systems and Biotechnical Centrifuge systems are well documented in the prior art. In particular CGC systems offer cost effective research environments for civil engineering research. The primary reason for the use of the centrifuge system is to allow investigative studies of geotechnical engineering systems that result from the dominant effect of "material self- weight".

Fundamentally the mechanical behaviour of soil is highly non-linear and dependent on related stress levels. In order to simulate these effects accurately within a small scale laboratory system it is necessary to be able to accurately reproduce such stresses. Accurate reproduction of these gravity stresses within a 1/nth scale model system requires a system that can produce a gravitational field that is n times those of the earth' s gravitational field. Therefore, CGC provide enabling means for producing such gravitational fields and hence providing a medium for physically modelling geotechnical engineering systems.

Employment of a drum centrifuge is the most convenient way to produce high acceleration fields for modelling purposes. However, the most common centrifuge systems currently in operation are those of a Beam Rotor design. These Beam Rotor centrifuges employ swing platforms that carry sample boxes. In order to counterbalance the sample boxes a second swing box or a specially designed counterweight is mounted on a boom diametrically opposite to the first sample box.

The Beam Rotor design is popular because it permits easier viewing of the samples while in operation. Additionally, the swing platforms result in gradation through the sample from top to the bottom, as opposed to that from one side to another as with Drum Ring Channel designs. Therefore, employing the Beam Rotor design simplifies the further analysis of the test sample. However, one major disadvantage of the Beam Rotor design, compared to that of the Drum Ring Channel design, is that air pressure build up occurs at the leading faces of the beam rotor. Therefore, the beam rotates at a slower speed, for a given drive power, than that found on a corresponding drum systems. This is particularly disadvantageous in scale modelling where very high g forces on the model are the desired effect. As a result of the reduced efficiency of the Beam Rotor design they generally require specially designed working environments that employ reinforced containment structures. Such features significantly increase the cost of building and running geotechnical and biotechnical centrifuges of the Beam Rotor design.

An object of the present invention is to provide a centrifuge system comprising modular components such that the centrifuge can be easily converted between a Beam Rotor and a Drum Ring Channel design.

According to the present invention there is provided a modular centrifuge comprising a main body, a removable test environment and a securing means, wherein the securing means connects the test environment to the main body of the modular centrifuge.

Most preferably the main body comprises a table mount, wherein the test environment is secured to the main body via the table mount.

Preferably the test environment comprises a drum ring channel. Alternatively the test environment comprises a beam rotor.

Preferably the securing means comprises a plurality of bolts.

Preferably the main body further comprises a motor, a drive axle and a drive axle pivot, wherein the combination of the motor, the drive axle and the drive axle pivot allow the test environment to pivot between, and rotate about, a substantially horizontal axis and a substantially vertical axis.

Preferably the drum ring channel comprises a plurality of locators and one or more sample compartment boxes.

Preferably the beam rotor comprises a base plate, a plurality of locators, one or more swing platforms, one or more sample compartment boxes and swing hinges associated with each sample compartment box.

Most preferably the swing hinges connect the sample compartment boxes to the swing platform, wherein the sample compartment boxes are free to pivot outwards under the force produced by rotational movement of the beam rotor.

Example embodiments of the present invention will now be described with reference to the following figures:

Figure 1 shows a drum ring channel for use with a modular centrifuge;

Figure 2 shows a beam rotor for use with the modular centrifuge;

Figure 3 shows the beam rotor as orientated when in use with the modular centrifuge;

Figure 4 shows the modular centrifuge with the drum ring channel rotating about:

(a) a horizontal axis; and

(b) a vertical axis; Figure 5 shows the modular centrifuge with the beam rotor rotating about: (a) a horizontal axis; and (b) a vertical axis.

Referring initially to Figure 1, a drum ring channel 1, for use in a modular centrifuge 2, is presented. The drum ring channel 1 can be seen to comprise a hollow circular body 3, two sample compartment boxes 4 and a plurality of locators 5.

Figure 2, presents a beam rotor 6, for use in the modular centrifuge 2. The beam rotor 6 can be seen to comprise a base plate 7, two sample compartment boxes 8 that are mounted on swing platforms 9 via a number of pivot hinges 10, and a plurality of locators 5. In Figure 2 the sample compartment boxes 8 are shown in a first position corresponding to centrifuge rest. When the modular centrifuge 2 is in motion the sample compartment boxes 8 pivot to a second position as shown in Figure 3.

Figure 4 presents the drum ring channel 1 in situ with the remaining components of the modular centrifuge 2. The modular centrifuge 2 can be seen to further comprise a base frame 11 a table mount 12, a motor 13, a drive axle 14, a drive axle pivot 15, and a computer control module (not shown) .

When deployed the drum ring channel 1 is bolted onto the table mount 12 via the interaction of bolts (not shown) with the locators 5. The modular centrifuge 2 is then available for use. Employing the sample compartment boxes 4 allows for the compartmentalisation of the drum ring channel 1. This aids in improving the test area efficiency when the modular centrifuge 2 is employed for small scale testing. A number of compartment boxes 4 may be incorporated in the drum ring channel 1 although in this embodiment only two are presented.

As is well documented in the prior art centrifuges are designed so as to incorporate an ability to change their main axis of rotation. This is achieved within the modular centrifuge 2 by varying the orientation of the drive axle 14 about the drive axle pivot 15 so as to move the rotation axis from a predominantly horizontal position, Figure 4 (b) , to that of a predominantly vertical position, Figure 4(a) . While the rotation axis is in the horizontal position it facilitates the preparation requirements of the drum ring channel 1.

If a user desires to use the modular centrifuge 2 in a Beam Rotor design they are simply required to unfasten the securing bolts that are employed to hold the drum ring channel 1 in place on the table mount 12. The same fixing means can thereafter be used to fix the beam rotor 6 in position on the table mount 12. Therefore, the modular centrifuge 2 now offers a testing facility, for Beam Rotor centrifuge testing, that is driven by the same motor 13 and drive axle 14 mechanisms as employed for the Drum Ring Channel centrifuge.

The present invention has the significant advantage that it provides two commonly used gravity testing environments within a single device, namely a Drum Ring Channel centrifuge or a Beam Rotor centrifuge. A further advantage of the present invention is that it provides a modular centrifuge that is easily interchangeable between the two well known working centrifuge designs, where both designs still meet with industry safety standards.

Further modifications and improvements may be incorporated without departing from the scope of the invention herein intended.

Claims

1. A modular centrifuge comprising a main body, a test environment and a securing means wherein the securing means provides a releasable connection means for the test environment and the main body such that the test environment is interchangeable between a drum ring channel and a beam rotor.

2. A modular centrifuge as in Claim 1, wherein the main body comprises a table mount, wherein the test environment is secured to the main body via the table mount.

3. A modular centrifuge as in any of the previous Claims, wherein the securing means comprises a plurality of bolts.

4. A modular centrifuge as in any of the previous Claims, wherein the main body further comprises a motor, a drive axle and a drive axle pivot, wherein the combination of the motor, the drive axle and the drive axle pivot allow the test environment to pivot between, and rotate about, a substantially horizontal axis and a substantially vertical axis.

5. A modular centrifuge as in any of the previous Claims, wherein the drum ring channel comprises a plurality of locators and one or more sample compartment boxes.

6. A modular centrifuge as in any of the previous Claims, wherein the beam rotor comprises a base plate, a plurality of locators, one or more swing platforms, one or more sample compartment boxes and swing hinges associated with each sample compartment box .

A modular centrifuge as in Claim 6, wherein the swing hinges connect the sample compartment boxes to the swing platform, wherein the sample compartment boxes are free to pivot outwards under the force produced by rotational movement of the beam rotor.