Thank you for your comment. After spending a lot on patent lawyers, it got rejected by the patent office citing "prior art" we attempted to point out that the prior art they compared my design to differed in many fundamental ways, but after going around in circles with the patent office for a while I ran out of money and couldn't proceed.
My design did not use any valves or impellors. It created a pulsatile waveform using eccentric gradual compression of silastic tubing. Nothing other than the interior tubing walls ever contacted the blood. The effect was sort of "wankel engine like" in that the effective chamber volume was gradually decreased as the pumps eccentric wound around.
My design did not use any valves or impellors. It created a pulsatile waveform using eccentric gradual compression of silastic tubing. Nothing other than the interior tubing walls ever contacted the blood. The effect was sort of "wankel engine like" in that the effective chamber volume was gradually decreased as the pumps eccentric wound around.
My design did not use any valves or impellors. It created a pulsatile waveform using eccentric gradual compression of silastic tubing. Nothing other than the interior tubing walls ever contacted the blood. The effect was sort of "wankel engine like" in that the effective chamber volume was gradually decreased as the pumps eccentric wound around.
There were older designs by others that used a very peristatic looking series of "fingers" to compress the tubing, but they suffered from a high index of hemolysis (blood cell destruction) I also seem to remember something about a magneto hydrodynamic drive, but it suffered from a large heat transfer to the blood.
When you add up these problems and then also try to make the device implantable it becomes really difficult.
I develped a pump for extracorporeal circulation of blood back in the mid 1970's and had to take a lot of these problems into account. My pump was pulsitile and had a very physiologic wave form including dichrotic notch. It also had 2 orders of magnitude less damage to red blood cells than the best pumps on the market at the time. (at least with the cow blood I experimented with) (Read on for an explanation of this) After spending a lot of money on patent lawyers, the device got shelved when I couldn't get a clear patent on it.
I think people here on slashdot are missing the point of continuous (non-pulsitile) flow. The elasticity of the arteries especially the aorta actually adds to the pulsitile nature of blood flow. There is an artifact seen in blood pressure measurements called the dichrotic notch that is a direct result of this. If it is absent it is an indication that hardening of the arteries has taken place. The main purpose of circulation is to get blood to tissues and organs. Once there, it has to infiltrate the organs deeply in order to properly transfer oxygen and nutrients and carry away wastes. We were evolved with pulsitile flow and as a result the perfusion of organs and tissues is better with this type of fluid dynamic. That doesn't mean it won't work with constant flow, only that it won't be as efficient. It may take several years before these inefficencies result in some kind of problems. An increase in plaque deposition comes to mind because the tissues arent stretching and contracting. The other problem with turbines and impellers is the "waring blender effect" where the blood cells are "chopped up" by the spinning blades. This leads to hemolysis (release of hemoglobin into the blood form broken red blood cells) which puts a strain on the kidneys which aren't beilng perfused properly because of the non pulsitile flow, etc. etc. you get the picture.
Anyway, it's interesting but not a permanent solution.
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Thank you for your comment. After spending a lot on patent lawyers, it got rejected by the patent office citing "prior art" we attempted to point out that the prior art they compared my design to differed in many fundamental ways, but after going around in circles with the patent office for a while I ran out of money and couldn't proceed. My design did not use any valves or impellors. It created a pulsatile waveform using eccentric gradual compression of silastic tubing. Nothing other than the interior tubing walls ever contacted the blood. The effect was sort of "wankel engine like" in that the effective chamber volume was gradually decreased as the pumps eccentric wound around.
My design did not use any valves or impellors. It created a pulsatile waveform using eccentric gradual compression of silastic tubing. Nothing other than the interior tubing walls ever contacted the blood. The effect was sort of "wankel engine like" in that the effective chamber volume was gradually decreased as the pumps eccentric wound around.
My design did not use any valves or impellors. It created a pulsatile waveform using eccentric gradual compression of silastic tubing. Nothing other than the interior tubing walls ever contacted the blood. The effect was sort of "wankel engine like" in that the effective chamber volume was gradually decreased as the pumps eccentric wound around. There were older designs by others that used a very peristatic looking series of "fingers" to compress the tubing, but they suffered from a high index of hemolysis (blood cell destruction) I also seem to remember something about a magneto hydrodynamic drive, but it suffered from a large heat transfer to the blood. When you add up these problems and then also try to make the device implantable it becomes really difficult.
I develped a pump for extracorporeal circulation of blood back in the mid 1970's and had to take a lot of these problems into account. My pump was pulsitile and had a very physiologic wave form including dichrotic notch. It also had 2 orders of magnitude less damage to red blood cells than the best pumps on the market at the time. (at least with the cow blood I experimented with) (Read on for an explanation of this) After spending a lot of money on patent lawyers, the device got shelved when I couldn't get a clear patent on it. I think people here on slashdot are missing the point of continuous (non-pulsitile) flow. The elasticity of the arteries especially the aorta actually adds to the pulsitile nature of blood flow. There is an artifact seen in blood pressure measurements called the dichrotic notch that is a direct result of this. If it is absent it is an indication that hardening of the arteries has taken place. The main purpose of circulation is to get blood to tissues and organs. Once there, it has to infiltrate the organs deeply in order to properly transfer oxygen and nutrients and carry away wastes. We were evolved with pulsitile flow and as a result the perfusion of organs and tissues is better with this type of fluid dynamic. That doesn't mean it won't work with constant flow, only that it won't be as efficient. It may take several years before these inefficencies result in some kind of problems. An increase in plaque deposition comes to mind because the tissues arent stretching and contracting. The other problem with turbines and impellers is the "waring blender effect" where the blood cells are "chopped up" by the spinning blades. This leads to hemolysis (release of hemoglobin into the blood form broken red blood cells) which puts a strain on the kidneys which aren't beilng perfused properly because of the non pulsitile flow, etc. etc. you get the picture. Anyway, it's interesting but not a permanent solution.