A system incorporating a balanced mechanical resonator and a method for vibration of a sample composed of granular material to generate motion of a powder sample inside the sample holder for obtaining improved analysis statistics, without imparting vibration to the sample holder support

Brunner, Will M.

Sarrazin, Philippe C.

NASA Technical Reports Server

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(12) United States Patent 
Sarrazin et al. 
(54) BALANCED MECHANICAL RESONATOR 
FOR POWDER HANDLING DEVICE 
(75) Inventors: Philippe C. Sarrazin, Palo Alto, CA 
(US); Will M. Brunner, Mountain View, 
CA (US) 
(73) Assignee: Olympus NDT, Waltham, MA (US) 
(*) Notice: 	 Subject to any disclaimer, the term of this 
patent is extended or adjusted under 35 
U.S.C. 154(b) by 732 days. 
(21) Appl. No.: 12/378,032 
(22) Filed: 	 Feb. 9, 2009 
(65) 	 Prior Publication Data 
US 2009/0235747 Al 	 Sep. 24, 2009 
Related U.S. Application Data 
(60) Provisional application No. 61/065,216, filed on Feb. 
8, 2008. 
(1o) Patent No.: 	 US 8,302,477 B2 
(45) Date of Patent: 	 Nov. 6, 2012 
(51) Int. Cl. 
G0IH13100 	 (2006.01) 
BOIL 3100 	 (2006.01) 
(52) U.S. Cl . ....................................... 73/579; 73/864.91 
(58) Field of Classification Search ..................... 73/579 
See application file for complete search history. 
(56) References Cited 
U.S. PATENT DOCUMENTS 
6,974,362 132 * 12/2005 Lindell et al ...................... 451/5 
7,113,265 131* 	 9/2006 Sarrazin et al . ................. 356/73 
* cited by examiner 
Primary Examiner Hezron E Williams 
Assistant Examiner Gregory 7 Redmann 
(74) Attorney, Agent, or Firm Ostrolenk Faber LLP 
(57) ABSTRACT 
A system incorporating a balanced mechanical resonator and 
a method for vibration of a sample composed of granular 
material to generate motion of a powder sample inside the 
sample holder for obtaining improved analysis statistics, 
without imparting vibration to the sample holder support. 
14 Claims, 3 Drawing Sheets 
https://ntrs.nasa.gov/search.jsp?R=20120016575 2019-08-30T23:16:07+00:00Z
U.S. Patent 	 Nov. 6, 2012 	 Sheet I of 3 	 US 8,302,477 B2 
5 
U.S. Patent 	 Nov. 6, 2012 	 Sheet 2 of 3 	 US 8 ,302,477 B2 
Start 	 ~~0
-) 
Load granular 
sample into 	 12 
sample holder 
Vibrate sample holder with 
balanced mechanical 
	 14 resonator at or near a 
resonance frequency 
Analyze the 
	 ~ 
 16 granular sample 
Remove sample ~ 18 
 from sample holder 
End 
FIGURE 2 
4 
3 
5 
z' 
U.S. Patent 	 Nov. 6, 2012 	 Sheet 3 of 3 	 US 8,302,477 B2 
FIGURE 3 
US 8,302,477 B2 
1 
BALANCED MECHANICAL RESONATOR 
FOR POWDER HANDLING DEVICE 
CROSS-REFERENCE TO RELATED PATENT 
APPLICATION 
This application relates to U.S. Provisional Patent Appli-
cation No. 61/065,216 filed on Feb. 8, 2008, entitled BAL-
ANCED MECHANICAL RESONATOR FOR POWDER 
HANDLING DEVICE, which is hereby incorporated herein 
in its entirety by this reference. 
STATEMENT REGARDING FEDERALLY 
SPONSORED RESEARCH 
The United States Government has certain rights to the 
subject matter of this invention pursuant to NASA contract 
number NNA06CQ54C. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to powder handling 
devices and, more particularly, to a powder handling device 
that comprises a mechanism to vibrate a powder sample 
holder during analysis in an analytical instrument. Specifi-
cally, one embodiment of the present invention provides a 
system incorporating a balanced mechanical resonator and a 
method for vibration of a sample composed of granular mate-
rial to generate motion of the powder sample inside the 
sample holder for obtaining improved statistics of analysis in 
an analytical instrument, without imparting vibration to the 
sample holder support. 
2. Description of the Prior Art 
Various devices for handling powder samples in analytical 
instruments are known. One known device is disclosed in 
U.S. Pat. No. 7,113,265 (Powder handling device for analyti-
cal instruments). 
When using a known non-balanced mechanical vibrator 
(i.e., a vibrator not fitted with a balancing mass to compensate 
the inertial forces of the primary mass), the inertial forces 
produced by the vibration are transmitted to the chassis of the 
sample holder of the powder handling device through the 
mounting links. This can result in vibration of other compo-
nents even faraway from the vibrator. Vibration energy is then 
wasted in these parasite vibrations, and the resulting ampli-
tude of vibration of the primary resonator is diminished. 
It would be desirable to provide a solution that overcomes 
the disadvantages of known powder handling devices. More 
particularly, it would be desirable to provide a mechanism 
that substantially eliminates vibrations transmitted to the 
chassis of the sample holder. It would also be desirable to 
reduce parasitic vibrations that reduce the amplitude of vibra-
tions applied to the powder sample being analyzed. 
SUMMARY OF THE INVENTION 
One embodiment of the present invention provides a sys-
tem and method for vibrating a sample composed of granular 
material to generate motion of the powder sample inside the 
sample holder without transfer of the vibrations to the struc-
ture to which the sample holder is mounted. The system and 
method in accordance with the present invention provide 
improved analysis statistics of a powder sample in an analyti-
cal instrument. 
In accordance with a preferred embodiment of the present 
invention a balanced resonator is provided for a powder ban- 
2 
dling device. The system and method in accordance with the 
present invention substantially eliminate the amount of vibra-
tion transmitted to the chassis of the sample holder so that 
unwanted vibration of the structure that mounts the sample 
5 holder is dramatically reduced compared to a non-balanced 
vibrator structure (i.e., a vibrator not fitted with a balancing 
mass to compensate the inertial forces of the primary mass). 
The vibration is decoupled from other mechanical compo-
nents of the system, making the vibration more stable and less 
10 
sensitive to the manner in which the device is mounted in an 
analytical instrument. 
Preferably, in accordance with one embodiment of the 
system and method of the present invention, the vibrator is 
15 designed for operation at resonance. Consequently, the sys-
tem and method in accordance with the present invention 
obtain large amplitudes of vibration with minimal actuator 
force. 
In accordance with a preferred embodiment of the system 
20 and method of the present invention, mechanical amplifica-
tion is provided. This allows obtaining vibration amplitudes 
far greater than that of the actuator. 
Also, in accordance with the system and method of the 
present invention, the noise level emitted by the system is 
25 reduced when the sample is vibrated. 
The foregoing and other objects, features, and advantages 
of the present invention will become more readily apparent 
from the following detailed description of various embodi-
ments, which proceeds with reference to the accompanying 
30 drawing. 
BRIEF DESCRIPTION OF THE DRAWING 
The various embodiments of the present invention will be 
35 described in conjunction with the accompanying figures of 
the drawing to facilitate an understanding of the present 
invention. In the figures, like reference numerals refer to like 
elements. In the drawing: 
FIG. 1 is a block diagram illustrating one embodiment of 
40 the system in accordance with the present invention compris- 
ing a balanced resonator for a powder handling device. 
FIG. 2 is a flow diagram illustrating a method in accor-
dance with one embodiment of the present invention. 
FIG. 3 is an isometric view of an alternative embodiment of 
45 the system in accordance with the present invention compris- 
ing a balanced resonator for a powder handling device. 
DETAILED DESCRIPTION OF THE PREFERRED 
EMBODIMENTS 
50 
Referring to the drawing figures, FIG. 1 shows a balanced 
resonator for a powder handling device. A sample holder 1 
contains granular material to be analyzed by an analytical 
instrument. When the analytical instrument uses X-rays, the 
55 sample holder 1 is fitted with one or several X-ray windows 
through which the analyses are performed. 
The sample holder 1 is attached to a sample holder arm 3 of 
a balanced mechanical resonator 2. A balancer arm 4 is fitted 
with a counterweight mass 5. An actuator 6 excites the reso- 
60 nator 2 at or near one of its resonance frequencies to obtain 
vibration in anti-phase, as indicated by the numeral 7. 
The structure of the actuator 6 may be piezoelectric, elec-
tromagnetic, pneumatic, or the like. For example, the actuator 
6 may be an APA60S actuator available from Cedrat located 
65 in Grenoble, France. In the embodiment such as shown in 
FIG. 1, the system benefits from a mechanical amplification, 
allowing vibration at higher amplitude than the actuator 
US 8,302,477 B2 
3 
stroke. The mechanical resonator 2 is preferably designed to 
have a resonance frequency best suited to the sample motion 
(typically, 1-3 kHz). 
A preferred embodiment of the method in accordance with 
the present invention is shown in FIG. 2, generally indicated 5 
by the numeral 10. A user loads the granular sample into the 
sample holder 1, as indicated by a step 12 shown in FIG. 2. 
During analysis in the instrument, the sample holder 1 is 
vibrated by the balanced mechanical resonator 2 at sufficient 
amplitude to obtain granular convection of the sample, as io 
indicated by a step 14 shown in FIG. 2. This is typically 
obtained when vibrating the system at or near a resonance 
frequency of the balanced mechanical resonator 2. The 
mechanical excitation is produced by the actuator 6. The 
configuration is such that the counterweight mass 5 vibrates 15 
in anti-phase with the sample holder 1, allowing cancellation 
of primary order inertial effects. This structure produces a 
sharp mechanical resonance that allows achieving high vibra-
tion amplitude with minimal force input from the actuator 6. 
The balanced structure of the vibrator limits the amount of 20 
vibration transmitted to the chassis through the mechanical 
assembly holding the vibrator. The granular sample is then 
analyzed, as indicated by a step 16 shown in FIG. 2. After 
analysis of the granular sample, the sample is removed from 
the sample holder 1, as indicated by a step 18 shown in FIG. 25 
2. Subsequently, another sample may be loaded into the 
sample holder 1 and analyzed, as indicated by the arrow from 
step 18 to step 12 shown in FIG. 2. 
In accordance with one contemplated alternative preferred 
embodiment shown in FIG. 3, a balanced resonator 2' com- 30 
prises two sample holders 1 and 5', in which one sample 
holder 5' acts as the counterweight mass. In this embodiment, 
the sample holders 1 and 5' balance each other. 
In accordance with another contemplated alternative 
embodiment, a non-symmetric resonator structure is pro - 35 
vided, in which a counterweight of substantially different 
mass than the sample holder vibrates at a different amplitude 
than the sample holder such that the inertial effects on both 
sides substantially cancel each other. 
In accordance with yet another contemplated alternative 40 
embodiment, the mechanical resonator may have more than 
one counterweight mass balancing one or several sample 
holders. 
In accordance with a further contemplated alternative 
embodiment, the sample holder and/or the counterweight 45 
mass is (are) suspended with multiple links/arms instead of 
the single arm structure shown in FIGS. 1 and 3. 
In accordance with yet another contemplated alternative 
embodiment, an actuator is provided, that can transmit an 
oscillating or pulsed force to the resonator with no direct 50 
permanent contact with the resonator. 
While the foregoing description has been with reference to 
particular embodiments and contemplated alternative 
embodiments of the present invention, it will be appreciated 
by those skilled in the art that changes in these embodiments 55 
may be made without departing from the principles and spirit 
of the invention. Accordingly, the scope of the present inven-
tion can only be ascertained with reference to the appended 
claims. 
What is claimed is: 	 60 
1. A balanced resonator for a powder handling device for 
granular material to be analyzed by an analytical instrument, 
comprising: 
• sample holder adapted to hold the granular material to be 
analyzed; 	 65 
• balanced mechanical resonator mountable to an external 
chassis, comprising a) a sample holder arm attached to  
4 
the sample holder in which the granular material is 
loaded and b) a balancer arm fitted with a counterweight 
mass; and 
an actuator to excite the resonator at or near one of its 
resonance frequencies to obtain vibration of the sample 
holder arm and balancer arm with respect to each other 
by imparting angular motion less than 360 degrees in 
anti-phase, the actuator producing a given excitation 
force to obtain convection of granular material loaded in 
the sample holder; 
wherein a mechanical amplification is produced to enable 
vibration at a higher amplitude than the actuator excita-
tion force; 
whereby vibrations transmitted to the external chassis are 
substantially eliminated. 
2. The balanced resonator of claim 1, further comprising an 
analytical instrument that emits X-rays, wherein the sample 
holder is fitted with one or more X-ray windows through 
which analyses are performed. 
3. The balanced resonator of claim 1 wherein the actuator 
comprises one of a piezoelectric, electromagnetic, or pneu-
matic device. 
4. The balanced resonator of claim 1 wherein the resonance 
frequency is in the range of approximately 1-3 kHz. 
5. The balanced resonator of claim 1 wherein the counter-
weight mass comprises another sample holder. 
6. A method for vibrating a sample in a powder handling 
device for granular material to be analyzed by an analytical 
instrument, comprising the steps of: 
loading the granular material into a sample holder; 
vibrating the sample holder with a balanced mechanical 
resonator at sufficient amplitude to obtain granular con-
vection of the granular material loaded in the sample 
holder, such that a counterweight mass of the balanced 
mechanical resonator and the sample holder are in angu-
lar motion less than 360 degrees with respect to each 
other and the counterweight mass vibrates in anti-phase 
with the sample holder, thereby allowing cancellation of 
primary order inertial effects. 
7. The method of claim 6 wherein the step of vibrating the 
sample holder with a balanced mechanical resonator at suffi-
cient amplitude to obtain granular convection of the granular 
material comprises vibrating the sample holder at or near a 
resonance frequency of the balanced mechanical resonator. 
8. The method of claim 6, further comprising the step of 
analyzing the granular material. 
9. The balanced resonator of claim 1 wherein a counter-
weight of substantially different mass than the sample holder 
vibrates at a different amplitude than the sample holder such 
that inertial effects substantially cancel each other. 
10. The balanced resonator of claim 1, further comprising 
at least a second counterweight mass fitted to the balancer 
arm. 
11. The balanced resonator of claim 5, further comprising 
at least a second counterweight mass fitted to the balancer 
arm. 
12. The balanced resonator of claim 1, further comprising 
at least a second sample holder attached to the sample holder 
arm. 
13. The balanced resonator of claim 10, further comprising 
at least a second sample holder attached to the sample holder 
arm. 
14. The balanced resonator of claim 1 wherein the actuator 
produces an oscillating or pulsed excitation force without 
direct permanent contact with the resonator. 


Balanced mechanical resonator for powder handling device

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