Blood Collection Monitor
————————————————- Abstract: Blood Collection Monitor is helpful for accurate blood collection; it’s a compact instrument to provide smooth and gentle rocking of homogenous mixing with anti coagulant ; i. e. without clot formation of blood cells during collection of blood from a donor. BLOOD COLLECTION PROCESS IS HAPPENING IN DIFFERENT ENVIRONMENTS. THE CHALLENGE TO PHLEBOTOMIST (One who draws blood for analysis or transfusion) IS TO MAKE EACH BLOOD COLLECTION PROCESS COMFORTABLE AND SAFE WITHOUT COMPROMISING QUALITY.
BLOOD COLLECTION MONITOR COMES INTO ROLE HERE; IT IS SPECIALLY DESIGNED TO MAKE STANDARDIZED HIGH QUALITY BLOOD COLLECTION WITH REDUCED WORK LOAD OF PHLEBOTOMIST. BLOOD COLLECTION MONITOR ENSURES CORRECT VOLUME OF BLOOD COLLECTION WITH CONSTANT AGITATION FOR BETTER COMPONENT YIELD. SO, THE CORRECT VOLUME OF BLOOD COLLECTION AND MIXING OF THE BLOOD AND ANTICOGULANT GENTLY AND PERIODICALLY DURING COLLECTION OF BLOOD; CAN BE DONE BY BLOOD COLLECTION MONITOR. 1. ————————————————- Introduction: B
LOOD COLLECTION MONITOR is an advanced device which is aimed to collect the blood prior to collection with use of latest technology in place of earlier, insufficient, conventional methods i. e. without accurate weight by using random movement. The main concept behind this project is use of mechanically provide rocking movement to blood and proper mixing with anticoagulants. Also restrict the blood flow from donor when particular limit is reached. I. e. 350ml or 450ml. This is done by load cell and by comparing signal activate the stopping clamp is activated.
As, sensing range of load cell is in mill volts; directly the signal can be given as input to the circuit because it will provide insufficient output. So, it is required to be properly amplified. So, the block diagram is designed taking into account this matter. Then comparing it with reference signal which is decided by many experiments. It activates the clamp and stops the rocking movement of plate when weight in blood bag is presented. It is approximate to the actual design but more function of the instrument by extra features like flow detector, flow rate measurement etc.
So, the component specifications may differ from the actual one. fig 1. blood bag fig 2. blood bag on plate of bcm 2. ————————————————- Requirement of project: As we all know that blood collection monitor is very helpful for collection of accurate blood, it’s a compact instrument that provide smooth and gentle rocking movement of homogeneous mixing with anti-coagulant, so in modern lifestyle most of the doctors prefer these types of instrument for collection of blood very accurately. Blood collection monitor is very helpful to donate blood. hat happen in past that there’s no such types of instruments were present so it is inaccurate random process for doctors to take blood from the donor and also sometimes improper mixing with anti coagulant lead to waste the valuable donated blood that process may not helpful to accurately blood collection. With the help of this modern instrument it is very easy for doctors to take the blood from the donor, and through this instrument may also required less effort. Collection of blood accurately and safely. 3. ————————————————- Generalized block diagram AND CIRCUIT DIAGRAM:
BLOCK DIAGRAME OFComparator CIRCUIT 5-PIN RELAY DC MOTOR CLAMP MOMENT (OPEN/CLOSE) Blood Collection Monitor POWER SUPPLY AC MAINS INSTRUMENTATION AMPLIFIER CIRCUIT WEIGHT MEASUREMENT UNITS/LOAD CELL DC MOTOR rocking MOMENT OF TRAY BLOOD Donor/BLOOD BAG CIRCUIT DIAGRAME OF Blood Collection Monitor 5-PIN RELAY Each block in briefly…… 1. Power supply to give DC supply to ICs and other devices. 2. Mechanical assembly to apply rocking movement of plate. 3. Load cell for blood bag weight measure. 4. Instrumentation amplifier for amplify the signal from load cell. 5. Comparator for obtaining stopping pulse to clamp. . 5-pin relay to connect supply to clamp when stop pulse is obtained. Modifications can be applied… * ADC- Analog-to- Digital Converter, Microcontroller, and display of weight. * Alarm circuit to indicating stopping operations. 4. ————————————————- DETAILED DESCRIPTION OF EACH BLOCK: 5. 1. POWER SUPPLY: This is the main block in any of the electronic as well as biomedical project. Its Main function is to provide electrical excitation. 5. 2. 1. COMPONENTS USED: * IC 7812, 7912(+12V,-12 V) * IC 7805, 7905(+5V,-5V) * IC 7815, 7915(+15V,-15V) * diode for bridge rectifier (4) capacitors of 1000 micro farads, 50 volts (2) * capacitors of 0. 1 micro farads (2*4) * center tapped transformer 18-0-18 5. 2. 2. CIRCUIT DIAGRAM: FIG 3. CIRCUIT DIAGRAM OF DC POWER SUPPLY (+/-5,+/-12,+/-15 V dc) 5. 2. 3. WORKING OF CIRCUIT: The working of this circuit is so simple . Mains supply is given to the 12-0-12 center-tapped transformer. Output of secondary winding is given to the bridge rectifier IC . Then to get peak-to-peak output voltage signal, capacitors are used. In lab-application, variable power supplies are preferred. 4. 2. ROCKING movement of plate and weight sensor:
Whole assembly made such that one side of plate is joined with DC motor and U shaped bended rod which can able to push and pull plate from one side as plate is fixed with assembly from center power to DC motor lead rocking or sea show type movement which we want. It is most important part of instrument as mixing blood with anticoagulant properly. Fig 5. DC motor shaft connected to assembly. Fig 4. assembly to provide rocking movement. Sensing weight of blood bag during donating the blood it is most important task as on this basis measuring, displaying, and further stopping of blood flow mechanism works.
To measure the blood weight we used load cell as a sensor. In load cell according to change in weight input output in mill volt also changes by using this basic principle weight sensing is done. Load cell has in built bridge balancing circuit with weight sensor. Fig 8. Cantilever beam connection. Fig 7. load cell. Fig 6. Internal circuit of load cell. Fig 9. Original data sheet by Rudra sensors. According to data sheet input 8-12dc volt given to cell and output in changes in millivoltags. Below is data sheet of load cell. 4. 2. 1. COMPONENTS USED: * 12 volt DC motor Wooden and iron assembly * Plate * 12 volt dc supply 4. 3. INSTRUMENTATION AMPLIFIER: This block provides sensor output signal the sufficient amplification so as to drive further circuits properly and without loading. Generally 3 Op-Amp instrumentation amplifiers are employed in biomedical projects. As load cell senses in range of mill volts, we have to amplify it in of 1000 gain. Instrumentation amplifiers are actually made up of 2 parts: a buffered amplifier OP1, OP2 and a basic differential amplifier OP3. The differential amplifier part is often essential when measuring sensors.
Because a sensor produces a signal between its terminals. The buffered amplifier OP1 and OP2 not only provides gain, but prevents the sensor resistance from affecting the resistors in the op amp circuit, and vice-versa! The gain can be calculated by: Where; R1=R3 and R5/R4 = R7/R6. (R5=RF). * Gain calculations: Gain (A) = (1+ (2*(R1/R2))*(RF/R4) Taking A=1000 & diving 1000 as 500*2, 1+2R1/R2=2 2R1/R2=1 2R1=R2 Taking R2=2K, R1 =1K. Now, RF/R4=500K R4=1K, RF=500K =1MOhm || 1MOhm = (1000000*1000000)/ (1000000+1000000) =500 K. 4. 3. 1. COMPONENTS USED: * IC OP07(3) Resistors of 1K (4 no’s) * Resistors of 2K (2 no’s) * Resistors of 1Mohm (2 no’s) * Power supply of 12 Vdc 4. 3. 2. CIRCUIT DIAGRAM: FIG. 10 CIRCUIT DIAGRAM OF INSTRUMENTATION AMPLIFIER 4. 3. 3. WORKING OF CIRCUIT: The instrumentation amp offers two useful functions: amplify the difference between inputs and reject the signal that’s common to the inputs. The latter is called Common Mode Rejection (CMR). OP1 and OP2 are the two input amp’s and connected in the non-inverting follower configuration. It is the solution for the high gain and high input impedance.
Note: This is of high gain circuit so before soldering it on GPB, connectivity check of all the components as per circuit diagram twice on bread-board is advisable. There may chances of unpredictable o/p due to IC saturation. 4. 4. COMPERATOR: It compares the input signal with reference signal. When input exceed from reference signal it gives positive saturation and negative saturation when less than reference signal. We are using 1 volt as a reference , as from experiment we get 1 volt output from instrument amplifier through load cell under 350ml blood beg. 4. 4. 1. Components used: 1 operational amplifier Op07 * Resistor 10k (3 no’s) * Protecting diodes (2 no’s) 4. 4. 2. CIRCUIT DIAGRAM: FIG 11. CIRCUIT DIAGRAM OF COMPERATOR BY USING IC OP07 4. 5 relay: Fig. 12 Basic relay construction A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal.
Here in our applications operation is must switched from rocking movement to clamp operation. (As comparator detects particular weight in plate rocking movements stops and clamp activated. ) Fig13. Pin diagram of 5pin relay 4. 5. 1. COMPONENT USED: * 5 PIN simple relay 4. 6. Stopping clamp: IV set passing from clamp that restrict the blood flow from donor. Fig 14. Clamp for restrict the blood flow When comparator generates stopping pulse from 5 pin relay it gives supply to DC motor and on its shaft rotation thread connected with clamp is going to pull and clamp is closed. Indicate that blood collection is completed.
Also disconnect supply from DC motor that leads stop rocking movement. Fig 15. In our project IV set passing through clamp. In real instrument this type mechanism done by clamp type electromagnet as shown in figure. That pulsed by controller and as magnet generate the clamp force fully attract and it restrict the further blood flow from donor. 4. 6. 1. COMPONENTS FOR CLAMP MECHANISM: 12volt dc motor Plastic clip, Thread, Rubber bend 5. ————————————————- Application of project: The application of blood collection monitor is very widely used in blood bank and also in hospitals.
Now a day’s almost all hospital’s doctor prefer these instrument for accurate collection of blood. Through this instrument we can easily collect the blood of donor and this instrument is also helpful in mixing the blood with anticoagulant so blood does not clot and also to collect the accurate amount of blood. Also indicate flow rate from donor to bag and error in flow rate whether any obstruction in donor vein in any case. Doctors and blood bank technicians prefer this instrument for the accurate collection of blood so we can say that its main application is in medical field and in hospitals. 6. ———————————————— Limitation: Blood collection monitor is a useful instrument for doctors and so accurate for collection of blood so we found no any limitation in blood collection monitor right now. But ours is designed for only 350ml blood collecting, as well as it has no any current weight display, flow indications. Ours angular rocking movement is slightly large and jerky. 7. ————————————————- FUTURE EXPANSIONS: * In future this instrument will be facilities with more necessary parameters like flow rate, blood temp. Detector etc. Though motor used to rotate the plate not generating much noise but it will be removed in future. * Now a day’s BCM is single unit but in future it may facilities with some storage space of bag. (that will be more useful in mobile blood bank) * In future whole assembly make by fiber that’s making instrument lighter than present model. 8. ————————————————- CONCLUSION: For Blood collection monitor we can say that it is useful instrument for collection of blood accurately for doctors and safe for donors. And that’s why it’s being more commonly used in most hospitals now a day.
From my side I conclude that to design a single unit of instrument is not possible without fundamental knowledge of electronics, controlling, basic of simple principles and last but not the least patience and faith in my work and strength. I also mention that repetitive work on any circuit remove basic doughty and also working problem. My project also teaches me the technical thoughts, human relationship. 9. ————————————————- References: * Books/manual/ Catalog:- * Manual of blood collection monitor of bioastate pvt. Ltd. * Catalog of Rajas enterprise ltd. * SEARCH ENGINES:- www. google. com * OTHER SITES:- * Google images blood collection monitor. * www. biomedprogects. com * Visited blood bank/industrial estate:- * Guideline of Apollo hospital blood bank. * Rudra sensors Ahmadabad. 10. ————————————————- cost of project: Item| Description| Quantity| Total| Electronics components| ResistorsCapacitorsVoltage regulator IC, OP-07| 15156, 4| ` 150/-| Load cell| -| 1| ` 950/-| Assembly| Wooden and iron shaft mechanism| -| ` 240/-| Others supporting| GPB, core, connecting leads| 4| ` 20/-| | | | TOTAL AMOUNT: ` 1,360/-| — Thank you —