Test apparatus for determining ignition characteristics of various metal in oxidizer environments simulating operating conditions for materials is invented. The test apparatus has a chamber through which the oxidizing agent flows, and means for mounting a stationary test sample therein, a powered, rotating shaft in the chamber rigidly mounts a second test sample. The shaft is axially movable to bring the samples into frictional engagement and heated to the ignition point. Instrumentation connected to the apparatus provides for observation of temperatures, pressures, loads on and speeds of the rotating shaft, and torques whereby components of stressed oxygen systems can be selected which will avoid accidental fires under working conditions

Benz, F. J.

Dixon, D. S.

Shaw, R. C.

English

NASA Technical Reports Server

United States Patent 1191 [11] Patent Number: 4,561,784 
Bern et al. [45] Date of Patent: Dec. 31, 1985 
2,686,211 8/1954 .............................. 422/78 x apparatus provides for observation of temperatures, 
3,053,073 9/1962 Baughman ................................ 73/7 
3,033,017 5/1962 Whitehead ................................ 73/7 
3,221,534 12/1965 Alfred 73/7 
3,343,399 9/1967 Baker ........................................ 73/7 
3,404,557 10/1968 Hecht et al. .............................. 73/7 
3,805,586 4/1974 Dodson et al. ........................... 73/7 
3,834,219 9/1974 Brauer ....................................... 73/7 11 Claims, 4 Drawing Figures 
pressures, loads on and speeds ofthe rotating shaft, and 
torques whereby components of stressed oxygen ....................................... tems can be selected which will avoid accidental fires 
under working conditions. 
DEVICE AND METHOD FOR 
FRICTIONALLY TESTING MATERIALS FOR 
IGNITABILITY 
Inventors: Frank J. Benz; Randall C. Shaw; 
David S. Dixon, all of Las Cruces, N. 
Mex. 
The United States of America BS 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
Assignee: 
Appl. No.: 571,616 
Filed: Jan. 17,1984 
Int. a . 4  ............................................. GOlN 25/00 
U.S. a. ............................................. 374/8; 73/7; 
374/46; 422/78; 436/155 
Field of Search ......................... 374/45, 46, 50, 8; 
73/7; 340/577; 436/155, 160; 422/78 
References Cited 
U.S. PATENT DOCUMENTS 
3,987,661 10/1976 Kamp et al. ............................ 374/8 
4,019,365 4/1977 Woo ...................................... 374/46 
4,165,924 VI965 Wolff .................................. 73/86 X 
0394736 7/1933 United Kingdom ................ 436/156 
FOREIGN PATENT DOCUMENTS 
0864085 9/1981 U.S.S.R. .................................. 374/8 
0885829 11/1981 U.S.S.R. .................................. 374/8 
Primary Examiner-Daniel M. Yasich 
Attorney, Agent, or Firm-Edward K. Fein; John R. 
Manning; Marvin F. Matthews 
[571 ABSTRACT 
Test apparatus for determining ignition characteristics 
of various metal in oxidizer environments simulating 
operating conditions for materials, the test apparatus 
has a chamber (6) through which the oxidizing agent 
flows, and means for mounting a stationary test sample 
(36) therein, a powered, rotating shaft (E) in the cham- 
ber rigidly mounts a second test sample (35). The shaft 
is axially movable to bring the samples into frictional 
engagement and heated to the ignition point. Instrumen- 
tation 16,32,48,49, 50, 51, 52, 53, 54 connected to the 
A 
https://ntrs.nasa.gov/search.jsp?R=19860009942 2020-03-23T06:53:33+00:00Z
U. S .  Patent Dec. 3 1,1985 Sheet 1 of 3 4,561,784 
U.S. Patent Dec. 31,1985 Sheet 2 of 3 4,561,784 
U. S. Patent Dec. 3 1,1985 Sheet 3 of 3 4,561,784 
G A S  TEMP 
F I G . 3  
P 7 f 
F IG .4  
4,561,784 
- 1  2 
combustible materials in engineering applications, 
under stressed oxidizer environments, and sensing the 
various parameters possibly leading to ignition of the 
test material. 
Another object is to provide novel means for protect- 
l. origin ing the test apparatus from damage due to burning de- 
The invention described herein was made in the per- bris from ignited test material. 
formance of work under a NASA contract and is sub- These objects and others hereafter appearing are 
ject to the provisions of Section 305 of the National attained in the apparatus herein disclosed which in- 
Aeronautics and Space Act of 1958, Public Law 85-568 lo cludes a body enclosing three aligned body parts sepa- 
(72 Stat. 435; 42 U.S.C. 2457). rably bolted together and with a central test chamber 
2. Field of the Invention communicating with the oxygen supply. An appropri- 
This invention relates to test apparatus for ranking or ately sealed and cooled, powered shaft extends axially 
evaluating materials, particularly metals, under opera- through the body and test chamber. Serially located in 
tional conditions of various high pressure oxidizer envi- l5 the test chamber are rotating and stationary test samples 
ronments in terms of wear characteristics, coefficients secured, respectively, to the shaft for rotation therewith 
of friction, temperatures, etc., bearing on or loading to and to the wall of the test chamber. The shaft is axially 
ignitability of the test material. movable by power means, connected to the shaft 
3. Background of the Invention through a load cell, for causing frictional engagement 
Devices for testing Systems and components for re- 2o between the test samples. Appropriate sensors, e.g. 
thermoplies, pyrometers, load cells, and tachometers 
are provided for measurements of static and dynamic 
phenomena such as frictional force, speeds, tempera- 
tures, and pressures. A copper protective sleeve is se- 
BRIEF DESCRIPTION OF THE DRAWINGS 
In the accompanying drawings, 
DEVICE AND METHOD FOR FRICTIONALLY 
TESTING MATERIALS FOR IGNITABILITY 
DESCRIPTION 5 
SPonse characteristics under Particular operating c o d -  
tions, as torque, r.p.m., environmental gas PreSSUrG 
friction* temperature* and wear are For 
instance, Whitehead U.S. Pat. No. 3,033,017 shows a 
device for identifying steels by sensing the light inten- 25 cured to the test chamber about the 
sity of sparks created by the abrasive action of a grind- 
ing wheel. Baughman U.S. Pat. No. 3,053,073 discloses 
a bearing material stress tester featuring a pair of oppos- 
loads on the rotating bearing specimen. Wolff U.S. Pat. 30 apparatus, 
No. 3,165,924 discloses a rocket nozzle material tester 
featuring a combustion chamber in which a propellant is 
ignited, producing heat and pressure within the cham- 
samples. 
itely-disposed to compressive FIG. 1 is a longitudinal cross-section though the test 
FIG. is a schematic representation of the test appa- 
ratus and powering means, parts being omitted for clar- .. 
ber in order to evaluate the resistance of a sample mate- 
rial. 
lty* 
35 FIG. 3 is a schematic representation of the test appa- 
Alfred et al U.S. Pat. No. 3,221,534 shows a friction 
tester featuring a hermetically sealed rotating environ- 
and 
is a section taken On line 4-4 Of 2* 
mental enclosure in which is supported a-weighted DESCRIPTION OF THE PREFERRED 
member which remains fixed in space under the effect EMBODIMENTS 
of gravity. One friction member is secured to the inside 40 
of the enclosure, and the second friction member is show the mechanical features Of the 
secured to the weighted member such that the two apparatus including the cylindrical body A with identi- 
members are in movable friction contact upon rotation cal end sections B and D and the Central section c 
of the enclosure. forming test chamber 6. The body sections are separa- 
In Baker U.S. Pat. No. 3,343,399, a rotating ball bear- 45 blY secured in alignment by bolts F (FIG. 2 and FIG. 4). 
ing plate abrades on a specimen. Depth of the circular The body is rotatably carried in OPPOsitelY extending 
path worn in the test specimen by the rotating balls is winglike SuPPOrtS I (FIG. 4) through steady rest rollers 
utilized as a measure of the wear qualities of the test 7. Supports 1 are slidable on rails 8 though linear bear- 
material. Dodson et a1 U.S. Pat. No. 3,805,586 discloses ings G mounted in Pillow blocks 
a device for testing cable used to arrest the flight of 50 on an adjustable Platform 9, adjustment nuts gl, base 9G 
landing aircraft on an aircraft carrier or the like. The and flooring 10. 
device applies tension and torque load to a specimen A ChmdJer shaft E extends entirely through the body 
cable while a drop weight is used to impart a sudden and has, at its right hand end, Powering means including 
contact force to the specimen. a 15 HP motor 11, a variable pitch belt transmission in 
Brauer U.S. Pat. No. 3,824,219 shows a tool wear 55 a housing 12, a speed control motor 13 and the drive 
tester in which a steel ball under load is reciprocated shaft 15. The drive shaft actuates chamber shaft E 
across a rotating test sample of metal sheet. Degree of through a timing belt 14 which drives shaft E (FIG. 2) 
wear on the ball is utilized as a measure of tool wear for and a spline 17 (FIG. 1) having a woodruff key 18 
the particular sheet metal sample. which shears at approximately 300 inch/pounds. 
A torquing plate 19l (FIG. 2) is suspended between 
of considerable concern in oxygen systems in engineer- the rails 8. It slides over the flats of plate 19 (FIG. 1) as 
ing applications, systems and devices for instanta- a backup wrench when the chamber bolts F are being 
neously testing materials under operating conditions in torqued. Shaft E, which in an exemplary embodiment is 
stressed oxygen environmental have not been available. about 12 inches (30 cm) long, is constructed of PH 
and 
Rails 8 are 
However, although metal ignition is a safety hazard 60 
. -  . 65 heated-treated, corrosion resistant steel. Sealing por- 
tions E-1 and E-2 of the shaft on opposite sides of the SUMMARY OF THE INVENTION 
Consequently, an object of this invention is to pro- 
vide apparatus for simulating operating conditions of 
test chamber are polished to 6 microinches (0.00015234 
mm) for sealing engagement, respectively, with radial, 
3 
4,56 1,784 
spring loaded cup seals 22-25 mounted in end-sections 
B and D, made of molydisulfide, glass-filled Teflon with 
17-7 PH springs. These seals are retained by copper 
fittings 26 and 27, themselves sealed by O-rings 28 and 
29. The seals are capable of functioning at peak shaft 
speeds in an active medium such as oxygen. 
Shaft E, at its left hand end, is threadedly secured to 
the inner member 30 of a thrust bearing assembly 30,31, 
the outer member 31 of which is, in turn, threadedly 
secured through a load cell 32 to the shaft 33 of a pneu- 
matic cylinder 34 for controlled axial shifting of cham- 
ber shaft E, for a purpose to be described. A second 
load cell 54u (FIG. 4) provides a reading of torsional 
forces on the body A. 
A cylindrical test sample holder 35 is pinned and 
pressed to the center of shaft E within test chamber 6 
for receiving the rotating sample 36 rigidly secured 
thereto. A stationary sample 37 is secured to the test 
chamber wall in normally spaced relation to the rotat- 
4 
apart to permit removal of burned metal debris and 
making any repairs necessary preparatory to succeeding 
test procedures. 
Readings from the instrumentation under controlled 
5 environments may be utilized to determine and evalu- 
ate: 
1. Ignition characteristics of the test materials, 
2. Materials ranking and selection for various oxidizer 
services (oxygen, halogens, oxides of nitrogen, etc.) 
3. Wear characteristics of material, 
4. Coefficient of friction of materials, 
5. Data acquired from simulated conditions to aid in 
While original development and successful testing of 
15 the invention has taken place in the aerospace program, 
the invention can simulate operating conditions of any 
industrial use of metals in a stressed oxidizer environ- 
ment and is applicable to aircraft and underwater tech- 
nology and other industrial technologies where high 
10 
design of components and systems. 
ing sample by means of holder 37a. A replaceable cop- 20 pressure oxygen or halogens are used. 
per sleeve 38 on the test chamber wall protects the 
chamber wall and center body member C from burning 
debris. The chamber end plate 39 shields seals 22,23 and 
their fitting 26. Stationary sample holder 378 protects 
seals 24 and 25 and their fitting 27. 
Precision positioning of the shaft through the seals is 
maintained by deep groove radial bearings 20 and 21 
and precision-bored bushings which are pressed into the 
inner race of the bearings and are close running fits with 
shaft E. 
The invention may be modified as will occur to those 
skilled in the art and exclusive use of all modifications as 
come within the scope of the appended claims is con- 
templated. 
25 We claim: 
1. A test device for evaluating ignitability of materials 
under simulated operating conditions in stressed, oxi- 
dizer environments comprising a body having a sealable 
test chamber, a rotationally and axially powered shaft 
30 extending axially through said chamber and with seals ~ 
Oxidizer gas is supplied to test chamber by means of 
inlet port 40 and exited through port 40a. Cooling agent 
(water) is circulated through ports 41,42,43 and 44 and 
copper fittings 26 and 27. 
INSTRUMENTATION 
Chamber 6 is designed for extensive instrumentation 
for ready observation and/or recording of the test pa- 
rameters, as suggested in the block diagram (FIG. 3). 
Various measuring devices, such as thermoplies 51 and 40 
two-color pyrometers 52 may be used where expedient. 
Test sample and test chamber temperatures are pro- 
vided at 48, 49, and 50. Tensional loads on chamber 
shaft E are taken from load cell 32. 
sured by a transducer 53. R.p.m. of shaft E is measured 
by magnetic pick-up tachometer 16 previously men- 
tioned. Frictional forces and torque are taken from a 
load cell 542 consisting of a moment arm 54 attached to 
body A and reacting against rails 8. In addition, the test 50 
chamber may be provided with a window for visual or 
video inspection of test events. Air cylinder tempera- 
ture and pressure may be read as at 55. 
The body is constructed of a nickel copper alloy 
which makes the apparatus durable in the harsh envi- 55 
ronment and high temperatures due to the frictionally 
created high temperature of the burning test samples. 
The chamber shaft is capable of speeds of 20,000 r.p.m. 
In operation, with the test samples as for example, 36 
and 37, in place on the respective holders of the shaft E 60 
and the test chamber wall, and the oxidizer gas and 
coolant flowing, shaft E is rotated and shifted axially 
leftwardly to cause rubbing contact between the op- 
posed ends of the samples. Carefd note is made of tem- 
peratures, pressures, r.p.m., and loads existing from time 65 
to time. The samples are frictionally heated by rubbing 
contact, if desired, until ignition occurs. Following the 
test, the three body sections may be unbolted and slid 
35 
Linear displacement of shaft E is dynamically mea- 45 
and bearings in said body on opposite sides of said 
chamber, means for securing a test sample to said shaft 
in said chamber for rotation with said shaft, a stationary 
wear surface of a sample secured to at least a portion of 
a wall in said chamber, powered means to shift the test 
sample on said shaft into frictional contact with said 
surface, means to supply oxidizer to said chamber, 
means to sense and record friction-powered tempera- 
ture and ignition of test sample. 
2. A test device as described in claim 1 in which said 
stationary surface is comprised of the material being 
tested. 
3. A test device as described in claim 2 in which said 
rotatable and stationary test samples are disposed end to 
end about said shaft for frictional abutment. 
4. A test device as described in claim 2 further includ- 
ing a protective sleeve of durable material surrounding 
the test materials in said chamber. 
5. A test device as described in claim 4 in which said 
sleeve is made of copper. 
6. A test device as described in claim 1 further pro- 
vided with window means in a wall of said chamber for 
observation of ignition of the test sample. 
7. A test apparatus as described in claim 1 further 
including cooling means for said seals. 
8. A test device as described in claim 1 further includ- 
ing load sensing means incorporated with said’shaft for 
determination of normal loads on the material being 
tested. 
9. A test device as described in claim 1 in which said 
body is constructed of a central chamber part and end 
shaft bearing parts separably secured together for ac- 
cess to said chamber. 
10. The method of evaluating a material for ignitabil- 
ity under simulated operating conditions and due to 
friction in a stressed, oxidizer environment comprising 
enclosing a plurality of test samples of like or dissimilar 
materials on a rotating shaft and a wall of a test chamber 
4,561,784 
5 6 
each of the samples having frictional contact surfaces in Sensing temperature conditions of said samples includ- 
a chamber containing the oxidizer and moving said ing thereof* 11. The method described in claim 10 further includ- 
samples into frictional contact with and relative to said ing sensing frictional loading between =id sample sur- 
surfaces of each sample under different conditions of 5 faces. 
stress to cause frictional heating of said samples, and * * * * *  
10 
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Device and method for frictionally testing materials for ignitability

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