SparkVent2 Ventilator Valve Cam Spark Vent 2
Description
WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! The ventilator is completely experimental and has not been approved or tested by any regulatory agency. If you choose to build it and use it you do so at your own and your patient’s risk. Please understand that these risks are huge to both the patient and yourselves and you should only consider building or using it when you have no other option and your only other alternative is catastrophic loss of life. You must make and take responsibility for the decision of whether to use the Sparkvent 2 Ventilator and accept the consequences thereof. Risks include but are not limited to serious physical injury, burns, disability and/or death to both the patient and the operator. This thing is simple pinch tube air valve system run off a cam for an experimental Covid-19 ventilator (named Spark Vent 2). More details on the ventilator can be found at these links; https://github.com/SparkVent/TheSparkVent http://sparkvent.org https://www.youtube.com/watch?v=2_yuuIKCDco&feature=youtu.be https://vimeo.com/405322505 The intent of this ventilator is to get it as simple as possible without the need to purchase expensive items such as solenoid vavles and electronics. The main component of the valves here is some silicone tube approximately 14mm OD and 2.6mm wall thickness. When pinched with some verniers I cannot blow through this tube for 4.2mm or less. I have used 3.5mm in the design so there is some room for component wear and deflection. UPDATE 13 April 2020 - The little motorgearbox is severely impacted when run at low speed and I do not believe it will last. Will be changing drive configuration to run through the pulley. Tips: 1. Do not run a PLA Cam against the PLA followers. The friction is very high. 2. So far ABS for the Cam and PLA for the followers is fine but ABS for the follower also is likely to be fine (not yet tested). One reason we are shying away from using PLA for the followers is if it is left in a hot environment under load it could deform and not properly function. 3. When assembling the cam and bearings do not tighten it up too much. Over compression of the cam print will cause deformation of the print and the bearing will no longer be concentric and have a wobble. This bearing wobble will require a greater un-even torque to turn the shaft. I can turn M8 bolt thread with my fingers. I have supplied two stl files for the camshaft. One with a smaller bore so the M8 bolt can be rotated into the print. With some epoxy or appropriate glue on the thread will most certainly help. Try not to get glue in the bearings! 4. I have been printing solid just to be safe. 5. The followers are tapered in width. You need to lay it flat on one of its side faces when printing. 6. This mechanism is designed to be screwed to a solid structure. The picture shows it screwed to a piece of ply. Don't use ply on your ventilator! It cannot be cleaned. On the machine shown in the videos I used a piece of a 25mm thick kitchen cutting board made from HDPE. 7. A simple 5mm rod has been used for a pin for the followers. An M6 bolt may be used but you will need to drill out the prints. An M6 is not as good if you have to quickly pull out the followers while the machine is operating. To straighten 5mm rod i hold one end in the vice and turn the other with a drill. 8. In the design i have separated the bottom pinch point as a separate part. I have supplied 3 different prints, 3.5 being the standard. When you are happy the cam valves are working properly don't forget to glue you selected bottom pinch in place. 9. Lightly sanding the parts that pinch the silicon tube with wet and dry paper to make the smooth is also recommended. This will help the silicon tube last. 10. Most of the time the motor drives the cam. For a brief moment the cam drives the motor. Materials - As shown in kit photo. - I have included in the prints a pulley wheel just in case you cannot source a geared motor like the one I'm using (https://www.jaycar.com.au/36rpm-12vdc-reversible-gearhead-motor/p/YG2734). This geared motor has a 5mm shaft. I have drilled a hole in the end of the m8 bolt and tapped an m3 through the side of the hex head. The motor peaks at 0.15amps so it is greatly over rated for the task. Running continuous for 10-20 days straight is another matter! - M8 bolt minimum 100mm long without the pulley. Minimum 125mm long with the pulley. - Skateboard bearings used (608 - 8mm ID, 22mm OD, 7mm wide).
Statistics
Likes
7
Downloads
0