Christmas 2002 I realized I would not have the funds I needed to finish my last year of college at Georgia Tech. I talked with a friend and we decided to attempt to find some consulting work. This seemed like a long shot. Thru some amazing circumstances I was contacted by a research professor who needed a unique computer controlled fluid pumping system to perform his research. Details below.
I scanned the quote. You should be able to view it here:
http://bschafer.me04.googlepages.com/QuoteFluid...
In this picture you can see the finished product sitting on the desk.
I don’t have too many pictures from this project.
In this picture you get another view of the project while it is being developed.
This is a picture of a room from my college apartment. We had 6 people living in a 3 bedroom apartment and this was one of the rooms.
If you couldn’t download the pdf, then here is an OCR of the scanned quote. It’s kinda tough to read.
System Overview
The Fluid Pumping System has been developed to provide experimental data on
the restriction of fluid flow due to magnetic particles in the fluid being subjected to a
strong magnetic field. The system is an attempt to model blood flow in the human body,
more specifically blood loss due to an open wound.
The major components of the system are a dual syringe fluid pump and related
controls, a pressure sensor, a field generator and corresponding power supply, and a data
acquisition system. The block diagram below shows the connection of the major
components.
The pump controller regulates the flow rate or pressure output of the pump. The
pump delivers fluid to the test specimen within the generated field. A pressure sensor
immediately before the field measures the pressure difference across the test specimen
with respect to atmospheric pressure. The data acquisition system collects the flow rate
from the pump, the pressure signal from the pressure sensor and the field strength from
the field generator.
Requirements of Major Components
Dual Syringe Pump
o Require a minimum amount of fluid.
Controllable flow rate, Controllable pressure.
o Produce time dependant flow rates or pressure waveforms.
o Provide pressures ranges and flow rates comparable to the human body.
Pressure Sensor
o Displace a minimum amount of fluid.
o Measure a pressure range comparable to the human body.
Data Acquisition Unit
e Have enough analog inputs for the flow rate, pressure, and field strengths.
o Have additional analog inputs for possible expansion of the system.
o Computer controlled software for convenient data collection.
Field Generator I Power Supply
Provided by customer.
Field Sensor
e Provided by customer.
Overview of the Syringe Pump
The main component of the Fluid Pumping System is the pump and the
corresponding control circuitry. The following will describe in general the function of the
dual syringe pump. The main components of the pump are:
0 Two syringes are used to pump the fluid.
e A system of tubing and one way valves are used to refill the syringes and direct
fluid along the desired path.
e A linear slide provides mechanical support and alignment to the syringes.
e A linear electric actuator drives the syringes.
e An analog position controller controls the position of the electric actuator.
e A waveform generator provides desired user flowlpressure inputs.
0 A feedback control system provides pressure control.
Notes:
e The system can use a variety of syringe sizes. Different syringe sizes can be used to
generate larger flow rates or much smaller more accurate flow rates. Given a fluid
sample size of 20mL, an 8 to lOmL syringe will be the default syringe size and
should handle the required pressures and flow rates.
The plungers of both syringes are attached to the electric actuator and are oriented in
opposite directions. As one syringe is closed pushing fluid through the system the
other syringe is refilling itself at the same flow rate.
The pressure sensor signal is compared to the desired pressure and a correcting
position signal is relayed to the analog position controller. This unit also must take
into account the limit switches of the electric actuator to change the actuator direction
at the end of each stroke.
General Operation
Detailed Instructions will be provided with the final instrument. The following
instructions give a general understanding of the operation of the instrument.
1) Inject fluid into the pump while bleeding air from the system.
2) Mount the syringes to the syringe pump.
3) Select the mode of operation:
a. Flow rate control
b. Pressure control
4) Select the input waveform to generate the desired flow rate or pressure waveform.
5) Enable pump to begin flow.
6) Begin data acquisition of pressure, flow rate, field strength, etc.
7) Set field generator to desired field strength.
8) Process collected data.
Quotes
While developing this system we tried to determine what type of control would be
beneficial for acquiring useful data. Four types of control were determined to be possibly
useful; Constant Flow, Time Varying Flow, Constant Pressure, Time Varying Pressure.
The first two types of control, constant flow and time varying flow, required no
feedback loop. The flow rate of the syringe pump is only a function of the velocity of the
plunger. Therefore, the flow rate can be controlled using only the input signal. Pressure
control requires a feedback loop fiom the pressure sensor because the pressure is a
function of the fluid propeaies, the flow rate and the various resistances in the system.
Both control systems require the same mechanical system to operate. Below two
quotes are given. The first quote is for the system that provides only constant flow and
time varying flow control. The second quote is for a system with the additional controls
to provide both flow and pressure control.
While the pressure control more closely models the human circulatory system it
may be less useful in collecting experimental data. The two quotes are to help you
determine if pressure control is justifiable to your research. Also, if you choose the flow
control only system, it is possible to later upgrade that system to have both flow and
pressure control if that becomes necessary.
Design/Consfruction Estimate for Flow Control Onlv
Materials
$ 5,720.00 Dual Syringe Pump and Controls
$ 1,400.00 Computer for Data Collection, Waveform Generator
$ 2,200.00 Pressure Sensor with AmplifierISignal Conditioner
$ 1,000.00 Data Acquisition System
$ 200.00 Misc.
Labor
$16,900.00 Labor – Estimated at $65.00/hr x 260 hrs.
$27,420.00 Total
This total represents the cost for a fluid pumping system with constant flow rate control
or time dependant flow rate control.
Project Duration: 10 weeks
Project material costs will need to be paid upfront in order to purchase the necessary
equipment and begin development. Labor payments will be made every 3 weeks at 30,
30, 30% with the remaining 10% retainer due net 60. The project will officially begin the
day money is transferred to cover material costs.
Design/Construction Estimate for Flow and Pressure Control
Materials
$ 9,220.00 Dual Syringe Pump and Controls
$ 1,400.00 Computer for Data Collection, Waveform Generator / iiOo
$ 2,200.00 Pressure Sensor with AmplifierISignal Conditioner
$ 1,000.00 Data Acquisition System
$ 200.00 Misc. 3/80 f3r f P J ~
Labor
$22,100.00 Labor – Estimated at $65.00/hr x 340 hrs.
$36,120.00 Total
This total represents the cost for a fluid pumping system with constant flow rate control,
time dependant flow rate control, constant pressure control, or time dependant pressure
control.
Project Duration: 12 weeks,
Project material costs will need to be paid upfront in order to purchase the necessary
equipment and begin development. Labor payments will be made every 4 weeks at 30,
30, 30% with the remaining 10% retainer due net 60. The project will officially begin the
day money is transferred to cover material costs.
System Pictures
1. Overview
2. Fluid Pump System
3. Test Section Mount
4. Dual Syringe Pump
(complete instructions)