Dead weight testing device uses a common force plane piston manometer to set accurate gage pressure in pounds per square inch. An additional piston gage easily adapts the device for absolute pressure calibration

Karcher, G.

Olson, G.

English

NASA Technical Reports Server

.July 1968
	 Brief 68-10264 
S	 NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Conceptual Dead Weight Device To Provide Pressure Calibration 
The problem: 
To develop a pressure calibration system capable of 
setting accurate pressures in either absolute or gage 
ranges. 
The solution: 
A dead weight testing device, using a common force 
plane piston manometer to set accurate gage pressures 
in pounds per square inch. An additional piston gage
easily adapts the device for absolute. pressure calibra-
tion. 
How it's done: 
The basic device, shown in the figure, is a cantilever 
system, formed by four cast aluminum structures A, 
B, C, and D. Structure A, externally supported, is 
connected to B, C, and D by pivot devices (E, F, G, 
and H),. Structures B, C, and D rotate in a small arc 
(continued ovcrleal) 
AMk 
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.
https://ntrs.nasa.gov/search.jsp?R=19680000264 2020-03-12T06:11:42+00:00Z
about the, pivots in A so that a parallelogram configura-
tion is constantly retained. A set of mechanical stops 
(P) limits the rotation to approximately one-half inch. 
Structure B, the levc r arm, has a rigid weight (J) and 
an adjustable counterweight (X) at one end, and 
a zero referencing assembly (W) at the other. 
Structure C contains an electric motor R which, 
through reduction gear trains, rotates two universal-
jointed shafts. These shafts rotate precise area pistons 
(S and T) in the absolute pressure assembly (N) and 
gage pressure assembly (M). Attached to a lower ex-
tension of structure C is a circular aluminum plate, 
upon which dead weights K and L are placed or re-
moved by a system of air-controlled lifting devices 
(0). 
In operation of the device, all weights are first re-
moved from the circular plate by the lifting devices. 
The tare weight or tare pressure in the system is elimi-
nated by adjusting the counterweight until a zero ref-
erence is established. 
The dead weights are then initially placed on the 
circular plate. This load, however, is not sensed by 
the system for the lower mechanical stop prevents 
the device from rotating with this addition. 
To obtain a gage pressure reading, air pressure is 
applied to the gage pressure assembly. This causes an 
upward force on the piston gage T, which in turn 
exerts a force on the thrust bearing of structure C. 
When the force is sufficient to overcome the. dead 
weight, structure C moves off the mechanical stop. An 
accurate- gage pressure reading is provided at the zero 
reference by a servo-controlled metering of the pres-
sure to the gage pressure assembly.
To obtain a reading in pounds per square inch 'ab-
solute, a vacuum is attached to the absolute pressure 
assembly. The vacuum acts against piston gage S to 
remove the atmospheric pressure value from the dead 
weights. The reading is then taken from the zero 
rierence. 
Notes: 
1. This unique calibration device uses the basic prin-
ciples of a primary standard, 'is relatively main-
tenance free, and is accurate to 0.05%. It is ca-
pable of calibrating more than one item during a 
calibration sequence, is designed to reduce space 
requirements, and can be used with an automatic 
readout system. 
2. This information should be of interest to manu-
facturers and users of pressure gages in a variety 
of fields. 
3. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10264 
Patent status: 
No patent action is contemplated by NASA. 
Source: G. Olson and G. Karcher 
of the Chrysler Corporation

under contract to

Marshall Space Flight Center

(MFS-14672)
. 
. 
Brief 68-10264	 Category 01


Conceptual dead weight device to provide pressure calibration

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server