Abstract:
A peristaltic engine including two members and a conduit with a varying cross-sectional area disposed on the outer surface of one of the two members in the form of a helix. Each member has an axis and an outer surface in close proximity of each other forming a pinch point therebetween. The conduit has a combustible fluid disposed therein. The pinch point causes the combustible fluid within the conduit to compress. Then, the combustible fluid expands when the cross-sectional area of the conduit increases, thereby causing the two members to rotate and produce torque along their axis.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 60/817,320, filed Jun. 29, 2006, the entire contents of which are herein incorporated by reference. 
     
    
     CROSS-NOTING TO RELATED APPLICATIONS 
       [0002]    This application is related to U.S. application Ser. No. 10/972,661, filed Oct. 25, 2004 entitled “HELICAL FIELD ACCELERATOR”, the entire contents of which are herein incorporated by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0003]    In the drawings: 
           [0004]      FIG. 1  shows a perspective view of a peristaltic engine comprising two parallel cylindrical rollers with a conduit that varies in cross-sectional area and in which the helical pitch increases along the axis of the peristaltic engine. 
           [0005]      FIG. 2  shows a top plan view of a peristaltic engine comprising two parallel cylindrical rollers with a conduit that does not vary in cross-sectional area and in which the helical pitch increases along the axis of the peristaltic engine. 
           [0006]      FIG. 3  shows a perspective view of a peristaltic engine comprising two parallel cylindrical rollers located inside a cylindrical structure having a conduit. 
           [0007]      FIG. 4  shows a perspective view of a peristaltic engine comprising a single roller and a conduit placed around a flat disk. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0008]    In general, the principle of the peristaltic engine of the invention comprises two parallel cylindrical rollers  8 ,  9  are mounted within a rigid frame in close proximity to each other, and are arranged so that when one rotates the other rotates in the opposite direction, as shown in  FIG. 1 . A heat resistant, collapsible conduit  10  is arranged around one of the rollers in a helical pattern in such a way that it makes one or more turns around the roller. “Pinch points” are created within the conduit  10  where it passes between the two rollers  8 ,  9 . These pinch points block the flow of fluid through the conduit  10 . As the rollers rotate, segments of fluid are drawn into the conduit and become trapped between successive pinch points. These segments travel forward along the rollers&#39; axis until the fluid reaches the end of the conduit  10 , where it is expelled. 
         [0009]    The cross sectional area of the conduit  10  is made to vary along its length in a specific manner, so that at some points on the roller, the conduit  10  has a large cross section and at others it has a quite small cross section. Specifically, the cross sectional area of the conduit  10  is large at its entrance and gradually decreases along the rollers&#39; axis. Since the interior volume of the conduit  10  is related to its cross sectional area, the volume of the conduit  10  likewise decreases along the rollers&#39; axis as well. Consequently, as the rollers rotate, the section of conduit  10  between any two pinch points undergoes a progressive reduction in volume. When the conduit  10  contains a compressible fluid, this reduction in volume compresses the segment of fluid trapped between the pinch points. 
         [0010]    If the fluid within the conduit is combustible, for example suppose that it consists of a mixture of air and gasoline, and if this mixture is ignited, this compression enables combustion of the mixture. In fact, if the ratio between maximal cross sectional area of the conduit and minimal cross sectional area is great enough (e.g., 70:1), then photodetonation, or spontaneous ignition, of the air-fuel mixture will occur within the conduit  10 . 
         [0011]    Suppose that after the point of maximal compression, the cross sectional area of the conduit  10  is made to increase. This will cause the volume between the two pinch points to also increase, thereby allowing the fluid within the trapped segment to expand. However, since this fluid has gained energy in the form of heat after combustion, the fluid itself aids in its expansion, pushing against the walls of the conduit as though to inflate it. This inflation force acts directly against the pinch point formed between the rollers  8 ,  9 . However, since the device comprises a rigid system, the only way for the rollers  8 ,  9  to relieve this force is through rotation. This resulting rotation produces torque at the rollers&#39; axis, causing the device to behave as an engine. In effect, the fuel air mixture would be compressed, ignited, burned in a controlled manner, and then decompressed in such a way that it continues to generate torque against the rollers  8 ,  9  until the mixture exits the device. The torque that is produced would be sufficient both to sustain this combustion cycle, as well as to drive external devices such as vehicles, generators, and the like. 
         [0012]    The helical pitch of the conduit  10  determines the rate at which the device uptakes air relative to the rotating speed. For example, if the helical pitch of the conduit is 5:1 and the surface speed of the rollers is 60 m/s, then air would flow into the device at 300 m/s, near the transonic regime. This enables the device to operate at lower rotating speeds for a given power output. With conventional gas turbines, the air intake speed generally does not exceed the tip speed. 
         [0013]    In aerospace applications, this would also allow the device to uptake air without first decelerating it, even when traveling at supersonic speeds. For example, with a rotating speed of 300 m/s and a helix pitch of 5:1, the device would be able to create vacuum in its intake even when traveling at 1500 m/s. 
         [0014]    The helical pitch could be made to increase along the rollers&#39; axis, as in  FIG. 1 , causing the ingested air to accelerate as it passes through the device. This would be useful in which it is desirable to produce thrust with the device. 
         [0015]    Note that varying the helix pitch will also change the volume of the crescents of conduit that are trapped between pinch points. In effect, varying the helical pitch could be used to cause compression and expansion without varying the cross sectional area of the conduit  16 , as illustrated in  FIG. 2 . This would possibly reducing manufacturing costs. 
         [0016]    Note that the helical pitch of the conduit may also be zero, meaning that the conduit  16  forms a loop around the rollers  18 ,  20 . Note that it may be desirable to use more than a single occlusion roller. For example, in one configuration of the device, the conduit makes a single loop around the conduit and there are four occlusion rollers. At any given point in time, air that is trapped between the first and second occlusion rollers would be in the process of being compressed, air trapped between the second and third rollers would be in the process of being mixed with fuel and combusting while it expands, and combusted fuel/air that is trapped between the third and fourth rollers would be in the process of expanding without additional fuel. 
         [0017]    Note that in some applications, it may be desirable to place two occlusion rollers  18 ,  20  inside the cylinder that contains the conduit  24 , as in  FIG. 3 . This configuration would reduce the amount of space used by the device. Note that in  FIG. 3 , although there are two occlusion rollers  18 ,  20 , in many applications it would be desirable to use only a single occlusion roller. 
         [0018]    In another realization of the device, the conduit  28  may be placed around a flat disk  30 , as in  FIG. 4 . 
         [0019]    Unlike conventional engines, the peristaltic engine of the invention does not employ sliding seals. This enables the peristaltic engine to operate at greater compression levels than a piston or turbine engine. The lack of sliding seals also reduces sensitivity to manufacturing tolerances and dimensional changes due to changes in temperature while the device is in operation. Furthermore, since sliding seals are typically a primary wear component, this design would enable greater service life and allow higher rotational speeds. 
         [0020]    The peristaltic engine of the invention would contain no reciprocating parts and would be perfectly balanced. The peristaltic engine also allows an arbitrarily long burn time for the fuel-air mixture, regardless of rotation speed or engine scale. This is accomplished simply by increasing the length of the rollers, thereby increasing the length of time that the combusting mixture remains within the engine. This results in more complete combustion even at very high rotating speeds. This would allow the device to maintain high efficiency even at very small scales, such as those used in experimental “micro engines”. 
         [0021]    While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.