Electromechanical assembly with movable hopper, commanded to put soil samples into inlet sorts of sampling valves, distributes metered volumes of soil samples into test cells

Debenham, C. H.

English

NASA Technical Reports Server

December 1971	 Brief 71-10481 
S NASA TECH BRIEF 
Ames Research Center	
-4:v 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
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be directed to the Technology Utilization Office, NASA, Code KT, Washington, D. f. 20546.
IM 
Distribution and Metering System for Soil Samples 
The problem:	 ,	 A dump port is also available to the hopper for re-
To design a remotely operated, lightweight system
	 jecting undistributed sample portions. 
for accurately distributing metered volumes of soil
	 When the hopper is commanded to service a given 
samples into a series of test cells,
	 valve inlet port, a reversible motor and lead screw 
Soil Hopper 
Soil Valve 
Inlet Port	 o	 0
Soil Control Brush 
Soil Control Brush
	 f 
Top Surface	 Instrument
Downspout
+^!^near Actuator] 
Seal Surface Ce ll Seal Plate 
Cleaning Soil Cell 
Brush
The solution: 
An electromechanical assembly with a movable 
hopper that can be commanded to put soil samples 
into the inlet sorts of a series of sampling valves. 
How it's done: 
The hopper accepts a 10 cc soil sample and dis-
tributes it on command to the various soil valve 
inlet ports (see fig.). The hopper follows any random 
sequence of commands, including repeated servic-
ing of any of the valve inlet ports, and retains any 
undistributed portion of the original 10 cc sample.
move it along the line of jravel, closing a series 
of microswitches used as position indicators. When 
the microswitch selected by the command control is 
closed, the motor stops. The inlet ports are sized to 
account for the small amount of over-travel inherent 
in this type of device. If a "fill" command is given, 
a 3 sec dc pulse is applied to the power solenoid, 
causing the hopper to move over the inlet port 
and allowing soil to fall into the port. A compressed 
helical spring returns the hopper to its original 
position, ready for command to another inlet port. 
(A dashpot and snubbers are included in the system 
to control accelerations.)	 . 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned .rights. 
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As the hopper moves away from the inlet port, its 
soil control brush sweeps across the port, leveling 
the soil content with the top surface of the instru-
ment to keep the soil volume accurately defined. The 
soil is held in the inlet port until the soil valve is 
commanded to operate. The linear actuator then 
unloads the toggle mechanism and breaks the seal 
formed between the soil cell and its seal plate. The 
plate is lifted clear of the lapped surfaces on the 
cell and is then translated, opening the cell. Simul-
taneously, the actuator moves the downspout to a 
position between the valve inlet port and the cell, 
allowing the defined volume of soil sample to drop 
into the cell. To close the cell, a reverse sequence is 
followed, after the seal surfaces have been swept. 
Notes: 
1. In the breadboard instrument, the soil valve 
inlet ports were fabricated to contain from about 0.1 
to 1 cc of soil sample.
2. Loss of sample from 'the 'hopper during excursion 
was found to be negligible, particularly when 
the particle size of the soil was greater than 0.05 
mm. 
3. Carryover of one sample into another and bridging 
in passageways are also negligible. 
4. Requests for additional information may be di-
rected to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: TSP7 1-10481 
Patent status: 
No patent action is contemplated by NASA. 
Source: C. H. Debenham of

TRW, Inc.

under contract to

Ames Research Center

(ARC-10429)
. 
. 
Brief 71-10481	 Category 07


Distribution and metering system for soil samples

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