Hydrochlorimetric Acid Heater

Introduction

The human body contains between 4 and 6 liters of blood, depending on the body size [1]. The main components of blood can be classified as the cell free plasma (50-60%) and erythrocytes (40-50%), while leukocytes and thrombocytes together accounts for only ~1% of total blood volume [2]. A blood bank is a cache or bank of blood or blood components, collected at the time of blood donation. It is stored and preserved for later use in blood transfusion [3]. Blood and blood product should be kept in cold temperatures to avoid hemolysis, preserve sterility and functional integrity of blood components.[5] Blood stored at +4°C in additive solutions can be kept for up to 35-42 days and typically display an in vivo recovery of 78-82% 24

On one surface, there is a groove with 2 mm of depth and width throughout the rod for placement of the serum tube. On another surface, 2 holes with 5 mm of diameter and depth had been designed for placement of heating sensors. In center of the contact heater, a hole with 5 mm of diameter is sought to contain two 50 watts ceramic heater providing the apparatus with the needed heat. A cover with 200 mm of length, 30 mm of width and 8 mm of height was designed, with a groove with 2 mm of depth and width which passes along it and is hinged to the rod which fits with the other groove on the rod to contain the blood and blood products tubes. The system consists of a hot air ventilation box with dimension of 150×200×60 mm. This box is divided into two parts with a grid plate. One part of this box which does not have an external wall is designed to contain blood and blood products, and the other part is architected to contain the fan and heater, while a fan of 80×80 mm dimension is placed on the external wall of which conducts hot air to blood bag. For hanging this box to the serum stand a hole with 8 mm of diameter is placed on the top of the box. The electrical circuit have two LM35 heat sensors with capacity of measuring 0 to 100◦C with an accuracy of 0.1◦C which measures the temperature of two calculated points in the hardware of apparatus. LM35 is a low voltage precision centigrade temperature sensor which provides a voltage output that is linearly proportional to the Celsius temperature. An Atmega8 microcontroller receives temperature from these sensors and calculates the median temperature. The installed optocoupler in this circuit can power on/off the heater with high accuracy by comparing the calculated temperature to the desired input obtained with the potentiometer