Oxygen Low Level Alarm System for High Volume Ventilator
1) For the High Volume Ventilator to work properly, it is important to maintain constant oxygen supply.
2) This Oxygen Low Level Alarm System is design to solve this problem.
3) This system not only alert the user for oxygen low level condition, but also maintain the constant flow of oxygen to the system during the user change of the oxygen tank.
4) This is achieved by having two oxygen tanks in the system, where one tank in work, the other will be in standby mode.
5) The schematic diagram of this system is as shown in Fig. 1 below :
6) As shown in Fig. 1 above, this system consists of pressure regulator, ON/OFF valve and pressure switch.
7) Each oxygen tank is having a pressure regulator which shown the tank pressure and the set output pressure.
8) In this case the set pressure is 5bar, while the pressure switch having cut OFF pressure of 3bar
9) When one oxygen tank is in used, its ON/OFF valve is turn to ON position, while the other oxygen tank in standby, its ON/OFF valve will turn to OFF position.
10) This pressure switch is controlled by an electrical circuit as shown in Fig. 2 below :
11) This electrical circuit consists of the pressure switch itself, a two pole 24VDC relay, a buzzer, a push button switch (RESET) and a 24VDC power supply.
12) During power ON, the buzzer will sound. The user just need to press the RESET button one time to turn it OFF, provided that the line oxygen pressure is above 3bar.
13) Let say at one time the line oxygen pressure is lower than 3bar and this trigger the pressure switch to cut OFF.
14) This will cause the buzzer to sound. It will continue to sound until the user switch to use the standby oxygen tank and the oxygen line pressure increase to more than 3bar.
15) Now, the user just need to press the RESET button one time to turn the buzzer OFF.
16) Now the user needs to turn the low oxygen tank, its ON/OFF valve to OFF position and change this oxygen tank with new one.
17) Then this new oxygen tank will becomes a standby tank.
