The objective of this experiment is to calibrate the Bourdon gauge, which is used to measure gauge pressure.

1. Koya University
Faculty of Engineering
School of Chemical & Petroleum Engineering
Chemical Engineering department
MECHANICAL FLUID
EXPERIMENT NUMBER SIX
Dead-weight piston gauge
Instructor: Mr. Ali & Miss. Hawzheen
Author Name: Aree Salah Tahir
Experiment Contacted on: 26/Nov/2013
Report Submitted on: 3/Dec /2013
Group:A

2. The aim of this experiment:
The objective of this experiment is to calibrate the
Bourdon gauge, which is used to measure gauge
pressure.

3. Introduction:
Dead Weight Pressure Gauge are used for calibrating
and standardizing pressure gauges Dead Weight
Pressure Gauge Testers are so designed and
manufactured that extremely small variations and very
small pressure scan be measured with great accuracy.
The standardizing pressure is developed by loading with
standardized weights a vertically arranged ram which
works in a cylinder filled with oil. This cylinder is
connected to an oil reservoir through an isolating valve
(which transfers the pressure to the gauge). A priming
pump, a pressure pump, pressure gauge adaptors etc.
are also connected to the cylinder. A set of standardized
weights, forth testing range of the tester, is supplied
with each instrument. A set of adaptors for different
sizes of pressure gauge threads is also provided along
with a set of spanners needle puller and a screw driver.

4. Theory:
Pressure sensor calibration
Variation in a pressure sensor reading may be calibrated, using
known pressures, to give a gauge reading in engineering units.
As has been seen in exercise A, the dead-weight calibrator
produces a known reference pressure by applying a mass to a
column of fluid. The pressure produced is where 𝐹𝑎 = 𝑚𝑔
Fa is the force applied to the liquid in the calibrator cylinder.
M is the total mass (including that of the piston)
g is the acceleration due to gravity
𝑷𝒂𝒄𝒕. =
𝑭
𝑨
𝑨 = 𝝅𝒓 𝟐
A is the area of piston.
The device for calibrating pressure gauges essentially
consist of two units:
1. The pressure gauge unit, this is where the device
needs to be calibrated and loads are measured with
units from bourdon gauge.
2. The load unit, this is the part where standard weight
are loaded and measured in the pressure gauge unit, the
higher the weights the more pressure it reads, the
pressure is transferred via oil filled line.

5. The layout unit:
The following sectional drawing shows load unit and
pressure gauge unit are connected as youcansee,
bothunitsare connected by means of a pipeline. When
the support is loaded with weights, the oil pressure in
the system increases. The seal between the piston and
the cylinder is metallic, with no other sealing element.
The fit has been very carefully designed to ensure that
the piston operates almost entirely without friction and
with minimal oil leakage. The weights are designed in
such a way that pressure increments of 0.5 bar are
possible Place the small weight on the weight support
first. Load and pressure measurement unit are
connected to each other via a pipe, when the piston is
loaded the pressure in the system rises and acts against
the spring on the manometer.

6. Performing the experiment:
-Open the overflow valve
-Remove the transport-cap
-If necessary topping up the hydraulic oil
-inserting the piston
To check the zero point of the bourdon gauge, proceed
as follows:
-Press the piston out of the cylinder using the hand
wheel
-Remove the piston and weight support
-Adjust the oil level in the open cylinder until the
cylinder is filled up to the edge
-The gauge pressure being tested should now indicate
zero, as it is only subject to ambient pressure.
-Assemble Bourdon’s pressure gauge with dead weight
tester
-Apply pressure in terms of weights on table and
measure the value of it on pressure gauge
-Repeat the procedure for ascending and descending
weights on table and corresponding

7. Apparatus:
weights
bourdon
gauge
weight
support
base plate

8. Discussion:
Define the calibrating curve and explain the purpose of it.
A calibration curve is the graphic or mathematic relationship
between the readings obtained in a process and the theoretical
value in a calibration. The relationship is often established as a
straight line rather than a curve.
The purpose of the Calibration curve is used to determine the
accuracy of the instrument and to ensure that readings from an
instrument are consistent with other instruments.
Draw the calibration curve between the Pm and Pact. Then
discuss it.

9. Calibration equation:
𝑌 = 𝑚𝑋 + 𝑏
𝑚 =
𝑦2 − 𝑦1
𝑥2 − 𝑥1
𝑚 = 1.004
𝑌 = 1.004𝑋 + 𝐵
We have some types of bourdon tube to find pressure
1.C-tube
2.spiral
3.twisted
4.helical