Patent Description:
Regenerative blowers-compressors are useful for moving large volumes of fluid, such as air and other gases, at pressures or vacuums comparatively lower than typical compressors, and comparatively higher than centrifugal fans. Unlike positive displacement compressors with their complex assembly and high parts count, and turbo compressors with their high operating speeds, regenerative blowers, also referred to as side channel blowers, are comparatively simple and medium speed machines that regenerate the pressure cycles of their bladed impellers continuously from an inlet to an outlet to create vacuum or pressure. Regenerative blowers are long-lasting, inherently simple in construction, low in cost, and commonly employed used in a wide range of applications where high fluid flow and low vacuum/pressure are required, such as pneumatic conveying, sewage aeration, vacuum lifting, vacuum packaging, packing equipment, printing presses, aquaculture/pond aeration, spas, dryers, dust/smoke removal, industrial vacuum systems, soil vapor extraction and chip removal for engraving equipment. The inherent advantages of regenerative blowers could be applied to an expanded range if the pressure and efficiency could be increased and the size decreased from standard pressures, efficiencies, and sizes. In particular, regenerative blowers have been shown to have ideal characteristics for fuel cell air supply systems and similar applications that achieve high efficiency while keeping the fluid stream free of contaminants such oil and grease from the bearings necessary to support the drive shaft.

A typical regenerative blower includes an impeller mounted directly to a motor shaft, which spins at the motor's speed, typically about <NUM>,<NUM> revolutions per minute, and in some cases up to <NUM>,<NUM> revolutions per minute. The impeller consists of numerous blades formed on its circumference. The number, size, spacing, angle, and specific shape of these blades contribute to the pneumatic performance characteristics of the blower. The impeller spins within a housing assembly having a channel on the inside of the housing that follows a radial path around the circumference of the impeller between an inlet and an outlet. As the impeller rotates, the fluid, such as air or other gas, is forced through the channel from the inlet to the outlet. The fluid is pressurized as it passes through the channel from the inlet to the outlet, whereby the fluid discharged through the outlet is at a higher relative pressure than that of the fluid entering the channel through the inlet. The intake region of the channel near the inlet is the low-pressure region of the blower, and the discharge region of the channel near the outlet is the high-pressure region of the blower. As the fluid is forced through the channel from the inlet to the outlet, the fluid is captured between each blade of the impeller and is pushed both outward and forward into the channel. The fluid follows the inner shape of the housing in a toroidal manner and returns to the base of the blade. The regeneration process is repeated over and over as the impeller spins, which gives the blower it's pressure/vacuum capabilities. A regenerative blower operates like a staged reciprocal compressor. While each blade-to-blade regeneration results in only a slight pressure increase, the sum of the slight pressure increases through the channel from the inlet to the outlet compound to yield comparatively high continuous operating pressures (in some cases over <NUM> psig (<NUM> kPa)) more commonly associated with more complex compressors, hence the designation, regenerative blowers-compressors. As in so many cases where a step change in the typical performance of a known technology is achieved, new deficiencies and new opportunities for both correction and new features become evident.

Regenerative blowers, such as those disclosed in <CIT> and <CIT>, are used to compress compressible fluids such as air and pump incompressible liquids such as water and or fuel. Accordingly, regenerative blowers are, by definition, regenerative compressors. The terms "regenerative blower" and "regenerative compressor" are, therefore, interchangeable. The fluid normally lost is a byproduct of compression within the compressor and is typically dealt with in a number of ways. Methods include allowing the fluid to pass through the compressor into the motor housing either pressurizing the motor housing or the fluid is allowed to pass through the motor housing and subsequently vented to atmosphere. Another technique attempts to eliminate the bypass fluid by placing a seal between the shaft and compressor housing eliminating the leak path.

Each method has drawbacks. In the case of allowing the fluid to pressurize the motor housing, the pressurized fluid can drive grease or oil from the motor bearings. In a similar manner, the fluid contained in the motor housing can be re-injected into the fluid path when the pressures in the compressor drop to lower values. If the fluid has encountered oil or grease in the motor housing the reintroduced fluid can be detrimental in certain devices which rely on clean compressed fluid such as medical devices or fuel cell stacks.

In the case of shaft seals, they come in both tight clearance non-contact types, and contact types. Non-contact seals are preferred in applications requiring high efficiency due to low friction, but the clearance creates leakage. Lower clearances can reduce, but not eliminate, leakage, at the penalty of tighter tolerances and higher costs.

Contact seals typically employ a compliant low friction material such as rubber or plastic that is in contact with the turning shaft to reduce leakage to very low levels. However, the resulting friction lowers compressor efficiency, and seal wear limits ultimate service life. Furthermore, a seal failure will allow fluid into the motor and bearings possibly washing the grease form the bearings and subsequently into the pressurized fluid stream. In the case of corrosive fluids, the fluid may damage the bearing and motor components.

Accordingly, it would be highly desirable to provide regenerative blowers-compressors that allow clearance seals to retain their advantages of low friction, long life and low cost, while generating leakage rates closer to non-clearance seals. In the case of clearance seals, it would also be highly desirable to provide regenerative blowers-compressors designed to have low leakage and pressure compensation for providing reduced seal wear and friction during low pressure operation.

According to the invention, a regenerative blower-compressor includes an impeller mounted to a drive shaft within a housing including a channel extending from an inlet adjacent to a low fluid-pressure region of the channel to an outlet adjacent to a high fluid-pressure region of the channel, the impeller extends radially outward through an annular volume within the housing from the drive shaft to blades in the channel, the impeller is configured to rotate for rotating the blades through the channel for forcing fluid through the channel from the inlet to the outlet in response to rotation of the drive shaft, the drive shaft extends from the impeller within the annular volume to into a shaft chamber within the housing, the shaft chamber is defined by a sidewall extending between an end wall and a bearing rotatably connecting the drive shaft to the housing, and the drive shaft is sealed to the sidewall by a radial shaft seal within the shaft chamber thereby dividing the shaft chamber into a first volume between the end wall and the radial shaft seal and a second volume between the bearing and the radial shaft seal, a first port coupled in fluid communication directly between the high fluid-pressure region of the channel and the first volume for venting fluid directly from the high fluid-pressure region of the channel to the first volume, and a second port coupled in fluid communication directly between the first volume and the low fluid-pressure region of the channel for venting fluid directly from the first volume to into the low fluid-pressure region of the channel. Preferably, a third port is coupled in fluid communication directly between the high fluid-pressure region of the channel and the second volume for venting fluid directly from the high fluid-pressure region of the channel to the second volume, and the second port additionally coupled in fluid communication directly between the second volume and the low fluid-pressure region of the channel for venting fluid directly from the second volume to into the low fluid-pressure region of the channel. The first volume is preferably larger than the second volume.

A regenerative blower-compressor includes an impeller mounted to a drive shaft within a housing including a channel extending from an inlet adjacent to a low fluid-pressure region of the channel to an outlet adjacent to a high fluid-pressure region of the channel. The drive shaft is mounted to the housing for rotation by rotary bearings. The low fluid-pressure region of the channel can simply be referred to as the low-pressure region of the channel, and the high fluid-pressure region of the channel can simply be referred to as the high-pressure region of the channel. The impeller extends radially outward through an annular volume within the housing from the drive shaft to blades in the channel. The impeller is configured to rotate for concurrently rotating the blades through the channel for forcing fluid through the channel from the inlet to the outlet in response to rotation of the drive shaft. The drive shaft extends from the impeller within the annular volume to into a shaft chamber within the housing, and the shaft chamber is inherently configured to receive, and be inherently pressurized by, leaked fluid, namely, the fluid that leaks through the housing to into the shaft chamber from the high-pressure region of the channel. The pressure in the channel continually increases from the inlet to the outlet due the regeneration action of the multiple blades rotating through the channel. As the pressure capability of the regenerative blower increases, proportionate pressure differentials between the high-pressure and low-pressure regions exist, in some cases only a few inches apart, without any firm physical barrier between them. The introduction of contact seals adds inherent cost and complication, decreases efficiency resulting from the inherent resulting friction, and introduces wear particles thereby defeating the inherent functional advantages of the regenerative blower.

It is an object of the invention to provide regenerative blowers configured to provide improved volumetric efficiency, to reduce loss of lubricant from the bearings connecting the shaft rotatably to the housing, and to stop or otherwise arrest the transfer of lubricant from the bearings into the process fluid stream. The regenerative blowers constructed and arranged in accordance with the invention capture the leaked fluid that leaks through the housing and which is normally lost and not put to a beneficial use and directly diverts it to the functional fluid path. By sending the leaked fluid to the low-pressure regions of the blower, the volumetric capacity of the blower is automatically increased and pressure acting on the bearing and seals is automatically relieved or otherwise eased. In some embodiments, the fluid from the high-pressure region of the channel is ported directly from the fluid flow path in the channel at the high-pressure region of the channel to the shaft chamber and directly from the shaft chamber to the fluid path in the channel at the low-pressure region of the channel. This is accomplished by ports, each of which can be a machined port, channel, drilled hole, cast in feature, hose, tube, or the like, in a singular location in certain embodiments and multiple locations in other embodiments. Again, the fluid captured and diverted to the low-pressure region of the channel automatically increases fluid flow through the channel and automatically relieves the pressure differential across the bearings and seals thereby arresting or at least reducing lubricant loss from the bearings.

Various embodiments of the invention are configured to use the circumferential pressure rise in a regenerative blower-compressor to tune the pressures in the vent ports to accomplish additional tasks in the blower-compressor, such as arresting or at least reducing high-pressure fluid leakage where the working fluid is flammable, dangerous, valuable, or similar circumstances where low to no leakage is desired. Additional functions can include accommodating different pressure needs of seals in and between two-stage regenerative blowers-compressors, and providing positive air pressure to ventilate motors and other incorporated components. Certain embodiments of the invention are also configured to operate at high pressures while overlapping the lower range of compressor systems.

For the balance of this disclosure, the term regenerative compressor and regenerative blower are used interchangeably. The interchangeability of these terms is well understood by skilled artisans. Moreover, it is known that regenerative machines are primarily used to move and compress gases, but are also used as liquid pumps in some cases. The same general advantages of this invention apply to them as well. Accordingly, the various embodiments of the invention are each referred to simply as regenerative blower-compressor.

Turning now to the drawings, in which like reference characters indicate corresponding elements throughout the several views, attention is directed in relevant part to <FIG> and <FIG>, in which there is illustrated a regenerative blower-compressor <NUM> including impeller <NUM> and housing <NUM>. Housing <NUM> includes annular housing <NUM> and can <NUM>. Annular housing <NUM> includes upper part or cover <NUM> and lower part, bottom, or base <NUM>. Annular housing <NUM> surrounds impeller <NUM>, and impeller <NUM> is rotatable within annular housing <NUM> about axis A of rotation, as is well-known in the art.

Annular housing <NUM> is an assembly of cover <NUM> and opposed base <NUM>, which are connected together to surround impeller <NUM> and define the customary toroidal flow channel <NUM>. Cover <NUM> and base <NUM> are rigidly affixed together with fasteners (not shown), such as nut-and-bolt fasteners, as is also well-known in the art. Annular housing <NUM> defines channel <NUM> for a fluid, such as a gaseous fluid, such as air or other gas, or a chosen liquid, inlet <NUM> to admit the fluid to channel <NUM>, outlet <NUM> to discharge the fluid from channel <NUM>, and annular volume <NUM> where impeller <NUM> resides, and this arrangement is also known in the art.

Impeller <NUM> is mounted directly on motor or drive shaft <NUM>. Drive shaft <NUM> passes or otherwise extends from impeller <NUM> downwardly through hole <NUM> in the center of base <NUM> of annular housing <NUM> to into a shaft chamber of housing <NUM>. Shaft <NUM> is arranged and rotates about axis A of rotation and is driven for rotation by an electric motor (not shown), which, in turn, imparts rotation to impeller <NUM> in the direction of arrow B for driving the fluid through channel <NUM> from inlet <NUM> to outlet <NUM>. Shaft <NUM> is customarily mounted for rotation to housing <NUM> by internal rotary bearings described below. Shaft <NUM> rotates impeller <NUM> at a chosen speed, such as from about <NUM>-<NUM> revolutions per minute, which is a common and well-known range, and beyond the upper limit of this range to about <NUM>,<NUM> revolutions per minute in some arrangements depending on the capability of the motor. Impeller <NUM> has numerous conventional blades <NUM> formed on its circumference.

Impeller <NUM> extends radially outward through annular volume <NUM> within annular housing <NUM> of housing <NUM> from axis A of rotation and shaft <NUM> to numerous impeller blades <NUM> in channel <NUM>. The number, size, and angle of blades <NUM> are chosen to define the pneumatic performance characteristics of blower-compressor <NUM>. Impeller <NUM> spins or otherwise rotates about axis A of rotation within annular housing <NUM>. As impeller <NUM> rotates, blades <NUM> rotate through channel <NUM> in the direction of arrow B, which forces the fluid through channel <NUM> from inlet <NUM> to outlet <NUM>. The fluid is increasingly pressurized as it passes through channel <NUM> from inlet <NUM> to outlet <NUM>, in which the fluid discharged through outlet <NUM> is at a higher relative pressure than that of the fluid entering channel <NUM> through inlet <NUM>. The fluid pressure in channel <NUM> inherently increases gradually from inlet <NUM> to outlet <NUM>. This is an inherent characteristic of regenerative blowers-compressors. The fluid thereby translates through channel <NUM> from a low fluid-pressure region <NUM> of channel <NUM> proximate to inlet <NUM> to a comparatively high fluid-pressure region <NUM> of channel <NUM> proximate to outlet <NUM>.

The intake region of channel <NUM> near, or otherwise adjacent to, inlet <NUM> is low fluid-pressure region <NUM> of blower-compressor <NUM>, and the discharge region of channel <NUM> near, or otherwise adjacent to, outlet <NUM> is high fluid-pressure region <NUM> of blower-compressor <NUM>. As the fluid is forced through channel <NUM> from inlet <NUM> to outlet <NUM> via rotating impeller <NUM>, the fluid is captured between each blade <NUM> on the circumference of impeller <NUM> and is pushed both outward and forward into channel <NUM> and then back to the base of each blade <NUM>. This regeneration process is repeated over and over as impeller <NUM> spins. It is this regeneration that gives blower-compressor <NUM> its inherent pressure/vacuum capabilities. Blower-compressor <NUM> thereby operates like a staged reciprocal compressor and while each blade to blade regeneration stage results in slight pressure increases, such as from <NUM>-<NUM> pounds per square inch gauge (psig) (<NUM>-<NUM> kPa) the sum of the slight pressure increases through channel <NUM> from inlet <NUM> to outlet <NUM> can yield comparatively higher continuous operating pressures, such as approximately <NUM> psig (<NUM> kPa).

Base <NUM> is carried by can <NUM>. Referring to <FIG> and <FIG> in relevant part, can <NUM> includes continuous sidewall <NUM> having outer surface <NUM>, inner surface <NUM>, upper edge <NUM>, and lower edge <NUM>. Horizontal top or head <NUM> is affixed to upper edge <NUM>. Horizontal base or bottom <NUM> is affixed to lower edge <NUM>. Continuous sidewall <NUM> extends upright from lower edge <NUM> affixed to bottom <NUM> to upper edge <NUM> affixed to head <NUM>. Head <NUM> and bottom <NUM> cooperates with inner surface <NUM> to form enclosed volume <NUM> in <FIG> configured to accept an electric motor for imparting rotation to drive shaft <NUM>. Base <NUM> is formed in, and is integral with, head <NUM>. Head <NUM> can be considered a part or otherwise an extension of base <NUM>. In an altemate arrangement, base <NUM> can be a separate part affixed to head <NUM> or to upper edge <NUM> of can <NUM> with fasteners or other chosen joinery.

In <FIG>, drive shaft <NUM> is elongate, is arranged and rotates about axis A of rotation, and includes lower end <NUM> and opposed upper end <NUM>. Lower end <NUM> of drive shaft <NUM> is mounted to bottom <NUM> of can <NUM> for rotation by bearing 114A fitted in socket <NUM> formed centrally in bottom <NUM>. Intermediate part <NUM> of drive shaft <NUM> between its lower end <NUM> and upper end <NUM> is mounted to head <NUM> of can <NUM> for rotation by bearing 114B fitted in socket <NUM> formed centrally in head <NUM>. Shaft <NUM> extends upright centrally through volume <NUM> from its lower end <NUM> mounted for rotation to bottom <NUM> by bearing 114B to its intermediate part <NUM> mounted for rotation to head <NUM> by bearing 114B, and with additional reference to <FIG> beyond bearing 114B through shaft chamber <NUM> formed in centrally head <NUM> on the underside of impeller <NUM> and to hole <NUM> formed centrally in head <NUM> and base <NUM> and beyond hole <NUM> centrally through and beyond impeller <NUM> to upper end <NUM> received and held by central recess <NUM> of cover <NUM> on the upper side of impeller <NUM>. Shaft chamber <NUM> in <FIG> and <FIG> is defined by sidewall <NUM> extending between end wall <NUM> and bearing 114B rotatably connecting intermediate part <NUM> of drive shaft <NUM> to head <NUM>.

As described above, volume <NUM> is configured to accept and house an electric motor operatively connected to drive shaft <NUM> between bearings 114A and 114B, whereby actuation of the electric motor imparts corresponding rotation to drive shaft <NUM>. Bearings 114A and 114B are identical and entirely conventional rotary bearings customarily lubricated with a chosen amount of a suitable lubricant, such as a customary chosen grease, a customary chosen oil, or both, sufficient to enable each of them to operate smoothly and orderly in accordance with standard operating parameters.

During operation of blower-compressor <NUM>, fluid in channel <NUM> inherently constantly leaks through housing <NUM> through the inherent clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C in <FIG> and <FIG> from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and downwardly in the direction of arrow D in <FIG> and <FIG> through the inherent clearance between drive shaft <NUM> and hole <NUM> formed in base <NUM> and head <NUM> into shaft chamber <NUM> thereby pressurizing shaft chamber <NUM> with the leaked fluid, termed herein as leaked or bypass fluid, from high fluid-pressure region <NUM>. The constant fluid leakage direction of arrow C from high fluid-pressure region <NUM> toward low fluid-pressure region <NUM> is perpendicular relative to drive shaft <NUM> and axis A of rotation of impeller <NUM>, and of arrow D is parallel relative to drive shaft <NUM> from volume <NUM> to shaft chamber <NUM>. The inherent leaking of fluid from high fluid-pressure region <NUM> toward low fluid-pressure region <NUM> in the direction of arrow C and downwardly in the direction of arrow D to into shaft chamber <NUM> is a function of the pressure differential across the interior volume of housing <NUM> during blower-compressor <NUM> operations. Accordingly, shaft chamber <NUM> of blower-compressor <NUM> is inherently configured in blower-compressor <NUM> to constantly receive fluid that constantly leaks through housing <NUM> between impeller <NUM> and annular volume <NUM> and between drive shaft <NUM> and hole <NUM> through base <NUM> and head <NUM> to into shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM>, and this is a known inherent characteristic of blower-compressor <NUM>.

In short, blower-compressor <NUM> includes impeller <NUM> mounted to drive shaft <NUM> within housing <NUM> including channel <NUM> extending from inlet <NUM> adjacent to into low fluid-pressure region <NUM> of channel <NUM> to outlet <NUM> adjacent to comparatively high fluid-pressure region <NUM> of channel <NUM>. Drive shaft <NUM> is mounted rotatably to housing <NUM>. Impeller <NUM> extends radially outward through annular volume <NUM> within housing <NUM> from drive shaft <NUM> to blades <NUM> in channel <NUM>. Impeller <NUM> is configured to rotate about axis A of rotation for rotating blades <NUM> through channel <NUM> for forcing fluid through channel <NUM> from inlet <NUM> to outlet <NUM> in response to rotation of drive shaft <NUM> about axis A of rotation. Drive shaft <NUM> extends from impeller <NUM> within annular volume <NUM> into shaft chamber <NUM> within housing <NUM>. Shaft chamber <NUM> is configured to constantly receive leaked fluid, i.e. the so-called bypass fluid that constantly leaks thereinto through housing <NUM> between impeller <NUM> and annular volume <NUM> and between drive shaft <NUM> and hole <NUM> through base <NUM> and head <NUM> from high fluid-pressure region <NUM> of channel <NUM>. Blower-compressor <NUM> described thusly is generally representative of a conventional single-stage regenerative blower. With the exception of the improvements to blower-compressor <NUM> discussed in the various arrangements and embodiments below, the further conventional details of blower-compressor <NUM> will readily occur to the skilled artisan and are not discussed.

Blower-compressor <NUM> is constructed and arranged to constantly and directly return/supply the bypass fluid leaked through housing <NUM> from high fluid-pressure region <NUM> into shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> from shaft chamber <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This is accomplished by port <NUM> in <FIG> and <FIG>.

Port <NUM> is operatively connected in fluid communication between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> to constantly receive fluid from shaft chamber <NUM> and constantly supply it to low fluid-pressure region <NUM> of channel <NUM>, whereby fluid constantly leaked through housing <NUM> to into shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM> is constantly and directly returned by port <NUM> into low fluid-pressure region <NUM> of channel <NUM> from shaft chamber <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is a return port or return re-vent coupled directly in fluid communication between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> for independently, directly, and constantly returning/venting the fluid constantly leaked to into shaft chamber <NUM> from high fluid-pressure region <NUM> of channel from shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM>. In the arrangement of <FIG> and <FIG>, port <NUM> is formed directly through the material of head <NUM> and base <NUM>, such as by drilling or machining or the like, from sidewall <NUM>, between end wall <NUM> and bearing 114B, to base <NUM> at low fluid-pressure region <NUM> of channel <NUM>, shown also in <FIG>, on the underside of impeller <NUM> in <FIG> and <FIG>. This directly couples shaft chamber <NUM> to channel <NUM> at low fluid-pressure region <NUM> in fluid communication enabling low fluid-pressure region <NUM> of channel <NUM> to receive fluid from shaft chamber <NUM> via port <NUM>.

During operation of blower-compressor <NUM>, fluid in channel <NUM> constantly leaks through housing <NUM> between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C in <FIG> from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and downwardly in the direction of arrow D between drive shaft <NUM> and hole <NUM> formed in base <NUM> and head <NUM> to into shaft chamber <NUM>. Accordingly, shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> to into shaft chamber <NUM>. Port <NUM> coupled directly in fluid communication between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> independently, directly, and constantly vents the leaked fluid from shaft chamber <NUM> to into low fluid-pressure region <NUM> of channel <NUM> from base <NUM> and thereby to into the functional fluid flow through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Accordingly, port <NUM> directly and constantly supplies/vents/ports the leaked fluid from shaft chamber <NUM> to into the fluid path of channel <NUM> through base <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This constant recirculation supply of the bypass fluid from shaft chamber <NUM> to into low fluid-pressure region <NUM> of channel <NUM> by port <NUM> inherently increases the fluid flow through channel <NUM> thereby inherently improving the volumetric efficiency and operation of blower-compressor <NUM>, and at the same time constantly relieves the pressure in shaft chamber <NUM>, which thereby arrests or at least reduces the pressure differential across bearing 114B at shaft chamber <NUM> to, in turn, thereby arrest or at least reduce lubricant loss from bearing 114B. Although blower-compressor <NUM> has one return port <NUM>, it can be formed with two or more separate return ports <NUM> in altemate arrangements at different locations between shaft chamber <NUM> and along low fluid-pressure region <NUM> of channel <NUM>.

In <FIG> and <FIG>, the previously described blower-compressor <NUM> is shown modified by radial shaft seal <NUM> thereby forming an alternate arrangement of a regenerative blower-compressor denoted at 50A. The reference numerals used in the description of blower-compressor <NUM> are also used where appropriate in the arrangement denoted at 50A.

In blower-compressor 50A, radial shaft seal <NUM> is within shaft chamber <NUM> of regenerative blower-compressor 50A between end wall <NUM> and bearing 114B, and is configured to seal drive shaft <NUM> to sidewall <NUM> between end wall <NUM> and bearing 114B thereby inherently dividing shaft chamber <NUM> into a first or upper volume 120A between end wall <NUM> and radial shaft seal <NUM> and a second or lower volume 120B between bearing 114B and radial shaft seal <NUM>. First and second volumes 120A and 120B are on either side of radial shaft seal <NUM>. First volume 120A is on the upper side of radial shaft seal <NUM>, and second volume 120B is on the opposite lower side of radial shaft seal <NUM>. Radial shaft seal <NUM> seals first volume 120A from second volume 120B, and thereby from bearing 114B at second volume 120B. In this arrangement, first volume 120A is greater than second volume 120B, and port <NUM> is coupled directly in fluid communication between first volume 120A of shaft chamber <NUM>, at sidewall <NUM> between radial shaft seal <NUM> and bearing 114B, and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> thereby enabling low fluid-pressure region <NUM> of channel <NUM> to receive bypass fluid from first volume 120A of shaft chamber <NUM>.

Blower-compressor 50A is constructed and arranged to constantly and directly return/supply leaked fluid, i.e. the so-called bypass fluid that constantly leaks from high fluid-pressure region <NUM> through housing <NUM> into first volume 120A of shaft chamber <NUM> from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM>. This is accomplished in blower-compressor 50A by the previously-described port <NUM>.

Port <NUM> is operatively connected in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> to constantly receive fluid from first volume 120A of shaft chamber <NUM> and constantly supply it to low fluid-pressure region <NUM> of channel <NUM>, whereby fluid constantly leaked into first volume 120A of shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM> is constantly returned by port <NUM> into low fluid-pressure region <NUM> of channel <NUM> from first volume 120A and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is a return port or return re-vent coupled directly in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> for independently, directly, and constantly returning/venting fluid constantly leaked into first volume 120A of shaft chamber <NUM> from high fluid-pressure region <NUM> from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is coupled in fluid communication directly between first volume 120A of shaft chamber <NUM>, at sidewall <NUM> between end wall <NUM> and radial shaft seal <NUM>, and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> at the underside of impeller <NUM>. This directly couples first volume 120A of shaft chamber <NUM> to channel <NUM> at low fluid-pressure region <NUM> in fluid communication enabling low fluid-pressure region <NUM> of channel <NUM> to receive fluid from first volume 120A of shaft chamber <NUM> via port <NUM>.

During operation of blower-compressor 50A, fluid in channel <NUM> constantly leaks through housing <NUM> through the inherent clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C in <FIG> and <FIG> from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and downwardly in the direction of arrow D through the inherent clearance between drive shaft <NUM> and hole <NUM> formed in head <NUM> into first volume 120A of shaft chamber <NUM>. Accordingly, first volume 120A constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 120A. Port <NUM> coupled directly in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> independently, directly, and constantly supplies/vents/ports the leaked fluid from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> from base <NUM> and thereby into the functional fluid flow through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Accordingly, port <NUM> constantly and directly supplies/vents/ports the bypass fluid directly and independently from first volume 120A of shaft chamber <NUM> into the fluid path of channel <NUM> through base <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This constant recirculation supply of the bypass fluid from first volume 120A shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> advantageously increases the fluid flow through channel <NUM> thereby inherently improving the volumetric efficiency and operation of blower-compressor 50A as described above in connection with blower-compressor <NUM>, and at the same time constantly relieves the pressure in first volume 120A of shaft chamber <NUM>, which thereby arrests or at least reduces the pressure differential across radial shaft seal <NUM>. This arrests or at least reduces lubricant loss from bearing 114B, and reduces the stress across radial shaft seal <NUM>, thereby inherently improving the useful functional life of radial shaft seal <NUM>, and across bearing 114B at second volume 120B of shaft chamber <NUM> to, in turn, thereby arrest or at least reduce lubricant loss from bearing 114B. Although blower-compressor 50A has one return port <NUM>, it can be formed with two or more separate return ports <NUM> in alternate arrangements at different locations between shaft chamber <NUM> and along low fluid-pressure region <NUM> of channel <NUM>.

In <FIG>, the previously described blower-compressor 50A is modified by port <NUM> thereby forming an altemate arrangement of a regenerative blower-compressor denoted at 50B. The reference numerals used in the description of blower-compressor 50A are also used where appropriate in the arrangement denoted at 50B.

Blower-compressor 50B is constructed and arranged to constantly and directly supply fluid directly from high fluid-pressure region <NUM> of channel <NUM> into second volume 120B of shaft chamber <NUM>. This is accomplished in blower-compressor 50B by port <NUM>, which is operatively connected in fluid communication directly between high fluid-pressure region <NUM> of channel <NUM> and second volume 120B of shaft chamber <NUM>. At the same time, blower-compressor 50B is constructed and arranged to constantly and directly return/supply leaked fluid, i.e. the so-called bypass fluid that constantly leaks from high fluid-pressure region <NUM> through housing <NUM> into first volume 120A of shaft chamber <NUM> from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM>. This is accomplished in blower-compressor 50B by the previously-described port <NUM>.

Port <NUM> is a supply port or re-vent operatively connected in fluid communication directly between second volume 120B of shaft chamber <NUM> and high fluid-pressure region <NUM> of channel <NUM> to constantly receive fluid from high fluid-pressure region <NUM> of channel and constantly supply it to second volume 120B, whereby fluid from high fluid-pressure region <NUM> of channel <NUM> is constantly supplied by port <NUM> to into second volume 120B. Port <NUM> is coupled in fluid communication directly between second volume 120B of shaft chamber <NUM>, at sidewall <NUM> between rotary shaft seal <NUM> and bearing 114B, and high fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> at the underside of impeller <NUM>. Port <NUM> is formed directly through the material of head <NUM>, such as by drilling or machining or the like, from sidewall <NUM>, between radial shaft seal <NUM> and bearing 114B, to base <NUM> at high fluid-pressure region <NUM> of channel <NUM> shown also in <FIG>, which is a top plan view of base <NUM>. This directly couples shaft chamber <NUM> to channel <NUM> at high fluid-pressure region <NUM> in fluid communication enabling shaft chamber <NUM> to receive fluid from high fluid-pressure region <NUM> of channel <NUM>.

During operation of regenerative blower-compressor 50B as described above in blower-compressor 50A, fluid in channel <NUM> constantly leaks through housing <NUM> through the clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C in <FIG> from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and downwardly in the direction of arrow D through the clearance between drive shaft <NUM> and hole <NUM> formed in head <NUM> into first volume 120A of shaft chamber <NUM> on the upper side of radial shaft seal <NUM>. Accordingly, first volume 120A of shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 120A of shaft chamber <NUM>. At the same time, port <NUM> coupled directly between second volume 120B of shaft chamber <NUM>, at sidewall <NUM> between radial shaft seal <NUM> and bearing 114B, and high fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM>, independently, directly, and constantly supplies/ports/vents fluid from high fluid-pressure region <NUM> of channel <NUM> into second volume 120B of shaft chamber <NUM> on the lower side of radial shaft seal <NUM>. The constant supply of first volume 120A with bypass fluid leaked into first volume 120A of shaft chamber <NUM> through housing <NUM> from high fluid-pressure region <NUM> of channel <NUM> and the concurrent constant supply of second volume 120B with fluid supplied directly into second volume 120B of shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM> by port <NUM> inherently equalizes the pressure on either side of, or otherwise across, radial shaft seal <NUM>.

Port <NUM> coupled directly in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> independently, directly, and constantly supplies/vents the leaked fluid from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> from base <NUM> and thereby into the functional fluid flow through channel <NUM>. Accordingly, port <NUM> constantly supplies/vents/ports the bypass fluid directly and independently from first volume 120A of shaft chamber <NUM> into the fluid path of channel <NUM> through base <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This constant recirculation supply of the bypass fluid from first volume 120A shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> advantageously increases the fluid flow through channel <NUM> thereby inherently improving the volumetric efficiency and operation of blower-compressor 50B as described above in connection with blower-compressor 50A, and at the same time constantly relieves the pressure in first volume 120A of shaft chamber <NUM>. While the pressure in first volume 120A is continuously relieved and first and second volumes 120A and 120B are continually supplied with fluid from high fluid-pressure region <NUM>, first volume 120A by fluid leaked into first volume 120A through housing <NUM> from high fluid-pressure region <NUM> and second volume 120B by fluid supplied directly into second volume 120B from high fluid-pressure region <NUM> by port <NUM>, the pressures in first volume 120A and second volume 120B equalize across radial shaft seal <NUM>, which thereby arrests or at least reduces pressure differentials across radial shaft seal <NUM> or otherwise on either side of radial shaft seal. This arrests or at least reduces lubricant loss from bearing 114B, and reduces the stress across radial shaft seal <NUM>, thereby inherently improving the useful functional life of radial shaft seal <NUM>, and across bearing 114B at second volume 120B of shaft chamber <NUM> to, in turn, thereby arrest or at least reduce lubricant loss from bearing 114B, according to the principle of the invention.

Although blower-compressor 50B has one supply port <NUM>, it can be formed with two or more separate supply ports <NUM> in altemate arrangements at different locations between shaft chamber <NUM> and along high fluid-pressure region <NUM> of channel <NUM>. Although blower-compressor 50B has one return port <NUM>, it can be formed with two or more separate return ports <NUM> in altemate arrangements at different locations between shaft chamber <NUM> and along low fluid-pressure region <NUM> of channel <NUM>.

In <FIG>, the previously described blower-compressor 50B is modified by port <NUM> and by a modification to port <NUM> thereby forming an altemate arrangement of a regenerative blower-compressor denoted at 50C. This regenerative compressor-blower is according to the invention. The reference numerals used in the description of blower-compressor 50B are also used where appropriate in the arrangement denoted at 50B.

Blower-compressor 50C is constructed and arranged to constantly and directly supply fluid directly from high fluid-pressure region <NUM> of channel <NUM> into first volume 120A of shaft chamber <NUM> and into second volume 120B of shaft chamber <NUM>. This is accomplished in blower-compressor 50C by port <NUM>, which is operatively connected in fluid communication between high fluid-pressure region <NUM> of channel and first volume 120A of shaft chamber <NUM>, and by the previously-described port <NUM>, which is operatively connected in fluid communication between high fluid-pressure region <NUM> of channel <NUM> and second volume 120B of shaft chamber <NUM>. At the same time, blower-compressor 50C is constructed and arranged to constantly and directly return/supply the fluid supplied into second volume 120B from high fluid-pressure region <NUM> of channel <NUM> by port <NUM> from second volume 120B into low fluid-pressure region <NUM> of channel <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM>, and to constantly and directly return/supply the fluid supplied into first volume 120A from high fluid-pressure region <NUM> of channel <NUM> by port <NUM> in addition to the leaked fluid, i.e. the so-called bypass fluid that constantly leaks from high fluid-pressure region <NUM> through housing <NUM> into first volume 120A of shaft chamber <NUM> from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM>. This is accomplished in blower-compressor 50C by port <NUM> that is modified in blower-compressor 50C by being operatively connected in fluid communication between low fluid-pressure region <NUM> of channel <NUM> and both first volume 120A and second volume 120B of shaft chamber <NUM>.

In regenerative blower-compressor 50C, port <NUM> is formed directly through the material of head <NUM>, from sidewall <NUM>, between end wall <NUM> and radial shaft seal <NUM>, and base <NUM> at low fluid-pressure region <NUM> of channel <NUM>, which thereby couples first volume 120A of shaft chamber <NUM> to channel <NUM> at low fluid-pressure region <NUM> in fluid communication. Port <NUM> is additionally configured with branch 130A, which operatively couples second volume 120B in fluid communication with port <NUM> and, thereby low fluid-pressure region <NUM> of channel <NUM>. In this arrangement, branch 130A extends through the material of head <NUM> from second volume 120B at sidewall <NUM> between radial shaft seal <NUM> and bearing 114B to port <NUM> between sidewall <NUM> of shaft chamber <NUM> and channel <NUM>.

Port <NUM> is a supply port or re-vent operatively connected in fluid communication directly between first volume 120A of shaft chamber <NUM> and high fluid-pressure region <NUM> of channel <NUM> to constantly receive fluid from high fluid-pressure region <NUM> and constantly supply it to first volume 120A of shaft chamber <NUM>, whereby fluid from high fluid-pressure region <NUM> of channel <NUM> is constantly supplied by port <NUM> to into first volume 120A thereby bypassing the bypass fluid leak pathway through housing <NUM> defined by arrows C and D. As shown in <FIG>, port <NUM> is formed directly through the material of head <NUM>, such as by machining or drilling or the like, from base <NUM> at the underside of impeller <NUM> at high fluid-pressure region <NUM> of channel <NUM> to sidewall <NUM> between end wall <NUM> and radial shaft seal <NUM>. Port <NUM> directly couples first volume 120A of shaft chamber <NUM> to channel <NUM> at high fluid-pressure region <NUM> in fluid communication enabling first volume 120A of shaft chamber <NUM> to receive fluid from high fluid-pressure region <NUM> of channel <NUM>.

During operation of regenerative blower-compressor 50C, fluid in channel <NUM> constantly leaks through housing <NUM> through the clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C in <FIG> from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and downwardly in the direction of arrow D through the clearance between drive shaft <NUM> and hole <NUM> formed in head <NUM> into first volume 120A of shaft chamber <NUM> thereby inherently constantly supplying first volume 120A of shaft chamber <NUM> on the upper side of radial shaft seal <NUM> with the leaked fluid, i.e. the bypass fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 120A of shaft chamber <NUM>. Accordingly, first volume 120A of shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into shaft chamber <NUM>. At the same time, port <NUM> coupled directly between first volume 120A of shaft chamber <NUM>, at sidewall <NUM> between radial shaft seal <NUM> and end wall <NUM>, and high fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM>, independently, directly, and constantly supplies/ports/vents fluid from high fluid-pressure region <NUM> of channel <NUM> into first volume 120A of shaft chamber <NUM>. First volume 120A of shaft chamber <NUM> on the upper side of radial shaft seal <NUM> thereby constantly receives fluid from high fluid-pressure region <NUM> by port <NUM>. Accordingly, first volume 120A constantly receives fluid from high fluid-pressure region <NUM> that constantly leaks into first volume 120A through housing <NUM> from high fluid-pressure region <NUM> of channel <NUM> and that is constantly supplied/ported/vented directly into first volume 120A from high fluid-pressure region <NUM> of channel <NUM> by port <NUM>. Also at the same time, port <NUM> coupled directly between second volume 120B of shaft chamber <NUM>, at sidewall <NUM> between radial shaft seal <NUM> and bearing 114B, and high fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM>, independently, directly, and constantly supplies/ports/vents fluid from high fluid-pressure region <NUM> of channel <NUM> into second volume 120B of shaft chamber <NUM> on the lower side of radial shaft seal <NUM>. This concurrent application of fluid from high fluid-pressure region <NUM> of channel to into first volume 120A and to into second volume 120B equalizes the pressure on either side of, or otherwise across, radial shaft seal <NUM>.

Port <NUM> coupled directly in fluid communication between low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> and first and second volumes 120A and 120B of shaft chamber <NUM> independently, directly, and constantly concurrently supplies/vents the fluid from first and second volumes 120A and 120B of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> from base <NUM> and thereby to into the functional fluid flow through channel <NUM>. Accordingly, port <NUM> constantly, concurrently, and directly supplies/vents/ports the fluid directly and independently from first and second volumes 120A and 120B of shaft chamber <NUM> into the fluid path of channel <NUM> through base <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This constant concurrent recirculation of the fluid from first and second volumes 120A and 120B to into low fluid-pressure region <NUM> of channel <NUM> advantageously increases the fluid flow through channel <NUM> thereby inherently improving the efficiency and operation of blower-compressor 50C, and at the same time constantly and concurrently relieves the respective pressures in first and second volumes 120A and 120B of shaft chamber <NUM>. While the pressures in first and second volumes 120A and 120B are continuously relieved by port <NUM> and first and second volumes 120A and 120B continually receive fluid from high fluid-pressure region <NUM> at the same time, first volume 120A by fluid supplied thereinto by port <NUM> and leaked thereinto through housing <NUM> from high fluid-pressure region <NUM>, and second volume 120B by fluid supplied directly thereinto from high fluid-pressure region <NUM> by port <NUM>, the pressures in first volume 120A and second volume 120B equalize across radial shaft seal <NUM>, which thereby arrests or at least reduces pressure differentials across radial shaft seal <NUM> or otherwise on either side of radial shaft seal. This arrests or at least reduces lubricant loss from bearing 114B, and reduces the stress across radial shaft seal <NUM>, thereby inherently improving the useful functional life of radial shaft seal <NUM>. Although blower-compressor 50C has two supply ports <NUM> and <NUM>, it can be formed with more in alternate arrangements at different locations between shaft chamber <NUM> and along high fluid-pressure region <NUM> of channel <NUM>. Although blower-compressor 50C has one return port <NUM>, it can be formed with two or more separate return ports <NUM> in alternate arrangements at different locations between shaft chamber <NUM> and along low fluid-pressure region <NUM> of channel <NUM>.

In <FIG>, the previously described blower-compressor 50A is modified by shaft chamber <NUM>, bearing 114C, radial shaft seal <NUM>, and port <NUM>, thereby forming a further arrangement of a regenerative blower-compressor denoted at 50D not forming part of the invention. The reference numerals used in the description of blower-compressor 50A are also used where appropriate in the arrangement denoted at 50D.

Like blower-compressor 50A, intermediate part <NUM> of drive shaft <NUM> is mounted to head <NUM> of can <NUM> for rotation by bearing 114B fitted in socket <NUM> formed centrally in head <NUM>, and shaft <NUM> extends upright beyond bearing 114B through shaft chamber <NUM> formed in centrally head <NUM> on the lower side of impeller <NUM> to hole <NUM> formed centrally in head <NUM> and beyond hole <NUM> centrally through impeller <NUM>. In blower-compressor 50D, shaft <NUM> extends upright beyond impeller <NUM> through shaft chamber <NUM> formed centrally in cover <NUM> on the upper side of impeller <NUM> to upper end <NUM> mounted to cover <NUM> of annular housing <NUM> for rotation by bearing 114C fitted in socket <NUM> formed centrally in cover <NUM>. Like bearings 114A and 114B, bearing 114C is an identical and entirely conventional rotary bearing lubricated with a chosen amount of a lubricant, such as a chosen grease, a chosen oil, or both, sufficient to enable bearing 114C to operate smoothly and orderly in accordance with standard operating parameters. Shaft chamber <NUM> is defined by sidewall <NUM> extending between impeller <NUM> and bearing 114C rotatably connecting upper end <NUM> of drive shaft <NUM> to cover <NUM>.

Radial shaft seal <NUM> is within shaft chamber <NUM> of regenerative blower-compressor 50D between impeller <NUM> and bearing 114C, and seals drive shaft <NUM> to sidewall <NUM> between end impeller <NUM> and bearing 114C thereby inherently dividing shaft chamber <NUM> into a first or lower volume 190A between impeller <NUM> and radial shaft seal <NUM>, and a second or upper volume 190B between radial shaft seal <NUM> and bearing 114C. First and second volumes 190A and 190B are on either side of radial shaft seal <NUM>, in which first volume 190A is on the lower side of radial shaft seal <NUM> and second volume 190B is on the opposite upper side of radial shaft seal <NUM>. Radial shaft seal <NUM> seals first volume 190A from second volume 190B, and thereby from bearing 114C at second volume 190B. In this embodiment, first volume 190A is greater than second volume 190B.

During operation of blower-compressor 50D, fluid in channel <NUM> inherently constantly leaks through housing <NUM> through the inherent clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, downwardly in the direction of arrow D through the inherent clearance between drive shaft <NUM> and hole <NUM> formed in head <NUM> into first volume 120A of shaft chamber <NUM>, and also upwardly in the direction of arrow E through the inherent clearance between annular volume <NUM> and impeller <NUM> into first volume 190A of shaft chamber <NUM>. Accordingly, first volume 120A of shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 120A of shaft chamber <NUM>. Additionally, first volume 190A of shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 190A of shaft chamber <NUM>, and also second volume 190B of shaft chamber <NUM> when fluid blows by radial shaft seal <NUM> into second volume 190B from first volume 190A. The constant fluid leakage direction of arrow C is perpendicular relative to drive shaft <NUM> and axis A of rotation of impeller <NUM> from high fluid-pressure region <NUM>, toward low fluid-pressure region <NUM>, and of arrows D and E is parallel relative to drive shaft <NUM> from volume <NUM> to shaft chamber <NUM>. The inherent leaking of fluid from high fluid-pressure region <NUM> toward low fluid-pressure region <NUM> in the direction of arrow C and downwardly in the direction of arrow D downwardly into shaft chamber <NUM> and in the direction of arrow E upwardly into first volume 190A and second volume 190B of shaft chamber <NUM> is a function of the pressure differential across the interior volume of housing <NUM> during blower-compressor 50D operations. Accordingly, shaft chambers <NUM> and <NUM> of blower-compressor 50D are each inherently configured to constantly receive leaked fluid that constantly leaks through housing <NUM> into shaft chambers <NUM> and <NUM> from high fluid-pressure region <NUM> of channel <NUM>.

Blower-compressor 50D is constructed and arranged to constantly and directly return the bypass fluid leaked to into first volume 120A of shaft chamber <NUM> through housing <NUM> from high fluid-pressure region <NUM> into low fluid-pressure region <NUM> of channel <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This is accomplished by the previously-described port <NUM> of the arrangement denoted at 50A. At the same time, blower-compressor 50D is also constructed and arranged to constantly and directly return the bypass fluid leaked to into shaft chamber <NUM> through housing <NUM> from high fluid-pressure region <NUM> to into low fluid-pressure region <NUM> of channel <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This is accomplished by port <NUM> in blower-compressor 50D.

As described above in the arrangement denoted at 50A, port <NUM> is operatively connected in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> to constantly receive fluid from first volume 120A of shaft chamber <NUM> and constantly supply it to low fluid-pressure region <NUM> of channel <NUM>, whereby fluid constantly leaked to into first volume 120A of shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM> is constantly and directly returned by port <NUM> into low fluid-pressure region <NUM> of channel <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is a return port or return re-vent coupled directly in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> for independently, directly, and constantly returning/venting fluid constantly leaked into first volume 120A of shaft chamber <NUM> from high fluid-pressure region <NUM> from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is coupled in fluid communication directly between first volume 120A of shaft chamber <NUM>, at sidewall <NUM> between end wall <NUM> and radial shaft seal <NUM>, and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> at the underside of impeller <NUM>.

In regenerative blower-compressor 50D, port <NUM> is formed directly through the material of cover <NUM>, such as by machining or drilling or the like, from sidewall <NUM>, between radial shaft seal <NUM> and bearing 114C, and cover <NUM> at low fluid-pressure region <NUM> of channel <NUM> at the upper side of impeller <NUM>, which thereby couples second volume 190B of shaft chamber <NUM> to channel <NUM> at low fluid-pressure region <NUM> in fluid communication. Port <NUM> is additionally configured with branch 210A similarly formed through the material of cover <NUM>, which operatively couples first volume 190A in fluid communication with port <NUM> and thereby low fluid-pressure region <NUM> of channel <NUM>. In this arrangement, branch 210A extends through the material of cover <NUM> from first volume 190A at sidewall <NUM> between impeller <NUM> and radial shaft seal <NUM> to port <NUM> between sidewall <NUM> of shaft chamber <NUM> and channel <NUM>.

Port <NUM> is operatively connected in fluid communication between low fluid-pressure region <NUM> of channel <NUM> and first and second volumes 190A and 190B of shaft chamber <NUM> to constantly return/supply fluid from first and second volumes 190A and 190B of shaft chamber <NUM> and constantly supply it to low fluid-pressure region <NUM> of channel <NUM>, whereby fluid constantly leaked into first and second volumes 190A and 190B of shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM> is constantly returned/supplied by port <NUM> into low fluid-pressure region <NUM> of channel <NUM> and thereby into the functional fluid path through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is a return port or re-vent coupled directly in fluid communication between first and second volumes 190A and 199B of shaft chamber <NUM> of cover <NUM> and low fluid-pressure region <NUM> of channel <NUM> for independently, directly, and constantly returning/venting leaked fluid, i.e. the bypass fluid leaked into first and second volumes 190A and 190B of shaft chamber <NUM> from high fluid-pressure region <NUM>. This directly couples first and second volumes 190A and 190B of shaft chamber <NUM> to channel <NUM> at low fluid-pressure region <NUM> in fluid communication enabling low fluid-pressure region <NUM> of channel <NUM> to receive fluid from first and second volumes 190A and 190B of shaft chamber <NUM> via port <NUM>.

During operation of blower-compressor 50D, fluid in channel <NUM> constantly leaks through housing <NUM> through the inherent clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and downwardly in the direction of arrow D through the inherent clearance between drive shaft <NUM> and hole <NUM> formed in head <NUM> into first volume 120A of shaft chamber <NUM>. Accordingly, first volume 120A of shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 120A of shaft chamber <NUM>. Port <NUM> coupled directly in fluid communication between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> independently, directly, and constantly vents the leaked fluid from first volume 120A of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> from base <NUM> and thereby into the functional fluid flow through channel <NUM> at low fluid-pressure region <NUM> of channel <NUM>. Accordingly, port <NUM> constantly and directly supplies/vents/ports the bypass fluid directly and independently from first volume 120A of shaft chamber <NUM> into the fluid path of channel <NUM> through base <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This constant recirculation supply of the bypass fluid from first volume 120A shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> by port <NUM> advantageously increases the fluid flow through channel <NUM> thereby inherently improving the volumetric efficiency and operation of blower-compressor 50D as described above in connection with blower-compressor <NUM>, and at the same time constantly relieves the pressure in first volume 120A of shaft chamber <NUM>, which thereby arrests or at least reduces the pressure differential across radial shaft seal <NUM>. This arrests or at least reduces lubricant loss from bearing 114B, and reduces the stress across radial shaft seal <NUM>, thereby inherently improving the useful functional life of radial shaft seal <NUM>, and across bearing 114B at second volume 120B of shaft chamber <NUM> to, in turn, thereby arrest or at least reduce lubricant loss from bearing 114B.

At the same time during operation of blower-compressor 50D, fluid in channel <NUM> constantly leaks through housing <NUM> through the inherent clearance between impeller <NUM> and annular volume <NUM> of housing <NUM> in the direction of arrow C from high fluid-pressure region <NUM> of channel <NUM> toward low fluid-pressure region <NUM> of channel <NUM> to shaft <NUM>, and upwardly in the direction of arrow E to into first volume 190A of shaft chamber <NUM>. Accordingly, first volume 190A of shaft chamber <NUM> constantly receives the so-called bypass fluid, the fluid that constantly leaks from high fluid-pressure region <NUM> into first volume 190A of shaft chamber <NUM>. As the pressure in first volume 190A increases, fluid can blow by radial shaft seal <NUM> from first volume 190A into second volume 190B. Port <NUM> coupled directly in fluid communication between first and second volumes 190A and 190B of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> at base <NUM> of annular housing <NUM> independently, directly, and constantly concurrently vents the leaked fluid from first and second volumes 190A and 190B of shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> from base <NUM> and thereby into the functional fluid flow through channel <NUM>. Accordingly, port <NUM> constantly and directly supplies/vents/ports the bypass fluid directly and independently concurrently from first and second volumes 190A and 190B of shaft chamber <NUM> into the fluid path of channel <NUM> through base <NUM> at low fluid-pressure region <NUM> of channel <NUM>. This constant recirculation of the bypass fluid from first and second volumes 190A and 190B shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM> advantageously increases the fluid flow through channel <NUM> thereby inherently improving the volumetric efficiency and operation of blower-compressor 50D as described above in connection with blower-compressor <NUM>, and at the same time constantly relieves the pressure in first and second volumes 190A and 190B of shaft chamber <NUM>, which thereby arrests or at least reduces the pressure differential across radial shaft seal <NUM>. This arrests or at least reduces lubricant loss from bearing 114C, and reduces the stress across radial shaft seal <NUM>, thereby inherently improving the useful functional life of radial shaft seal <NUM>.

Although blower-compressor 50D has one return port <NUM> between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM>, it can be formed with two or more separate supply ports <NUM> in alternate arrangements at different locations between shaft chamber <NUM> and along low fluid-pressure region <NUM> of channel <NUM>. Although blower-compressor 50D has one return port <NUM> between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM>, it can be formed with two or more separate return ports <NUM> in altemate arrangements at different locations between shaft chamber <NUM> and along low fluid-pressure region <NUM> of channel <NUM>.

Those having ordinary skill in the art will readily appreciate that new and improved regenerative blowers-compressors with shaft bypass fluid re-vents are disclosed, which are simple in structure, and harvest and divert fluid from the high fluid-pressure region <NUM> of channel <NUM> to the low fluid-pressure region <NUM> of channel <NUM> for improving volumetric efficiency, relieving stress across radial shaft seals, and for arresting lubricant loss from the rotary bearings <NUM>.

Regenerative blower-compressor <NUM> includes impeller <NUM> mounted to drive shaft <NUM> within housing <NUM> including channel <NUM> extending from inlet <NUM> adjacent to low fluid-pressure region <NUM> of channel <NUM> to outlet <NUM> adjacent to high fluid-pressure region <NUM> of channel <NUM>. Impeller <NUM> extends radially outward through annular volume <NUM> within housing <NUM> from drive shaft <NUM> to blades <NUM> in channel <NUM>. Impeller <NUM> is configured to rotate for rotating blades <NUM> through channel <NUM> for forcing fluid through channel <NUM> from inlet <NUM> to outlet <NUM> in response to rotation of drive shaft <NUM>. Drive shaft <NUM> extends from impeller <NUM> within annular volume <NUM> into shaft chamber <NUM> within housing <NUM>. Shaft chamber <NUM> is configured to receive fluid leaked through housing <NUM> into shaft chamber <NUM> from high fluid-pressure region <NUM> of channel <NUM>. Port <NUM> is coupled in fluid communication directly between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> for venting fluid directly from shaft chamber <NUM> into low fluid-pressure region <NUM> of channel <NUM>. Shaft chamber <NUM> is defined by sidewall <NUM> extending between end wall <NUM> and bearing 114B rotatably connecting drive shaft <NUM> to housing <NUM>. In the regenerative blower denoted at 50A, drive shaft <NUM> is sealed to sidewall <NUM> by radial shaft seal <NUM> within shaft chamber <NUM> thereby dividing shaft chamber <NUM> into first volume 120A between end wall <NUM> and radial shaft seal <NUM> and second volume 120B between bearing 114B and radial shaft seal <NUM>. First volume 120A is configured to receive fluid leaked through housing <NUM> into first volume 120A from high fluid-pressure region <NUM> of channel <NUM>, and port <NUM> is coupled in fluid communication directly between first volume 120A of shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM>. First volume 120A is greater than second volume 120B.

Another arrangement of a regenerative blower-compressor 50B includes impeller <NUM> mounted to drive shaft <NUM> within housing <NUM> including channel <NUM> extending from inlet <NUM> adjacent to low fluid-pressure region <NUM> of channel <NUM> to outlet <NUM> adjacent to high fluid-pressure region <NUM> of channel <NUM>. Impeller <NUM> extends radially outward through annular volume <NUM> within housing <NUM> from drive shaft <NUM> to blades <NUM> in channel <NUM>. Impeller <NUM> is configured to rotate for rotating blades <NUM> through channel <NUM> for forcing fluid through channel <NUM> from inlet <NUM> to outlet <NUM> in response to rotation of drive shaft <NUM>. Drive shaft <NUM> extends from impeller <NUM> within annular volume <NUM> to into shaft chamber <NUM> within housing <NUM>. Shaft chamber <NUM> is defined by sidewall <NUM> extending between end wall <NUM> and bearing 114B rotatably connecting drive shaft <NUM> to housing <NUM>. Drive shaft <NUM> is sealed to sidewall <NUM> by radial shaft seal <NUM> within shaft chamber <NUM> thereby dividing shaft chamber <NUM> into first volume 120A between end wall <NUM> and radial shaft seal <NUM> and second volume 120B between bearing 114B and radial shaft seal <NUM>. First volume 120A is configured to receive fluid leaked through housing <NUM> to into first volume 120A from high fluid-pressure region <NUM> of channel <NUM>. First port <NUM> is coupled in fluid communication directly between high fluid-pressure region <NUM> of channel <NUM> and second volume 120B for venting fluid directly from high fluid-pressure region <NUM> of channel <NUM> into second volume 120B. Second port <NUM> is coupled in fluid communication directly between first volume 120A and low fluid-pressure region <NUM> of channel <NUM> for venting fluid directly from first volume 120A into low fluid-pressure region of channel <NUM>. First volume 120A is larger than second volume 120B.

Yet another arrangement of a regenerative blower-compressor 50C includes impeller <NUM> mounted to drive shaft <NUM> within housing <NUM> including channel <NUM> extending from inlet <NUM> adjacent to low fluid-pressure region <NUM> of channel <NUM> to outlet <NUM> adjacent to high fluid-pressure region <NUM> of channel <NUM>. Impeller <NUM> extends radially outward through annular volume <NUM> within housing <NUM> from drive shaft <NUM> to blades <NUM> in channel <NUM>. Impeller <NUM> is configured to rotate for rotating blades <NUM> through channel <NUM> for forcing fluid through channel <NUM> from inlet <NUM> to outlet <NUM> in response to rotation of drive shaft <NUM>. Drive shaft <NUM> extends from impeller <NUM> within annular volume <NUM> to into shaft chamber <NUM> within housing <NUM>. First port <NUM> is coupled in fluid communication directly between high fluid-pressure region <NUM> of channel <NUM> and shaft chamber <NUM> for venting fluid directly from high fluid-pressure region <NUM> of channel <NUM> to shaft chamber <NUM>. Second port <NUM> is coupled in fluid communication directly between shaft chamber <NUM> and low fluid-pressure region <NUM> of channel <NUM> for venting fluid directly from shaft chamber <NUM> to into low fluid-pressure region <NUM> of channel <NUM>.

Still another arrangement of a regenerative blower-compressor 50C includes impeller <NUM> mounted to drive shaft <NUM> within housing <NUM> including channel <NUM> extending from inlet <NUM> adjacent to low fluid-pressure region <NUM> of channel <NUM> to outlet <NUM> adjacent to high fluid-pressure region <NUM> of channel <NUM>. Impeller <NUM> extends radially outward through annular volume <NUM> within housing <NUM> from drive shaft <NUM> to blades <NUM> in channel <NUM>. Impeller <NUM> is configured to rotate for rotating blades <NUM> through channel <NUM> for forcing fluid through channel <NUM> from inlet <NUM> to outlet <NUM> in response to rotation of drive shaft <NUM>. Drive shaft <NUM> extends from impeller <NUM> within annular volume <NUM> to into shaft chamber <NUM> within housing <NUM>. Shaft chamber <NUM> is defined by sidewall <NUM> extending between end wall <NUM> and bearing 114B rotatably connecting drive shaft <NUM> to housing <NUM>. Drive shaft <NUM> is sealed to sidewall <NUM> by radial shaft seal <NUM> within shaft chamber <NUM> thereby dividing shaft chamber <NUM> into first volume 120A between end wall <NUM> and radial shaft seal <NUM> and second volume 120B between bearing 114B and radial shaft seal <NUM>. First port <NUM> is coupled in fluid communication directly between high fluid-pressure region <NUM> of channel <NUM> and first volume 120A for venting fluid directly from high fluid-pressure region <NUM> of channel <NUM> into first volume 120A. Second port <NUM> is coupled in fluid communication directly between first volume 120A and low fluid-pressure region <NUM> of channel <NUM> for venting fluid directly from first volume 120A into low fluid-pressure region <NUM> of channel <NUM>. Third port <NUM> is coupled in fluid communication directly between high fluid-pressure region <NUM> of channel <NUM> and second volume 120B for venting fluid directly from high fluid-pressure region <NUM> of channel <NUM> into second volume 120B. Second port <NUM> is additionally coupled in fluid directly between second volume 120B and low fluid-pressure region of channel <NUM> for venting fluid directly from second volume 120B to into low fluid-pressure region <NUM> of channel <NUM>. First volume 120A is larger than second volume 120B.

Still another arrangement of a regenerative blower-compressor 50C includes impeller <NUM> mounted to drive shaft <NUM> within housing <NUM> including channel <NUM> extending from inlet <NUM> adjacent to low fluid-pressure region <NUM> of channel <NUM> to outlet <NUM> adjacent to high fluid-pressure region <NUM> of channel <NUM>. Impeller <NUM> extends radially outward through annular volume <NUM> within housing <NUM> from drive shaft <NUM> to blades <NUM> in channel <NUM>. Impeller <NUM> is configured to rotate for rotating blades <NUM> through channel <NUM> for forcing fluid through channel <NUM> from inlet <NUM> to outlet <NUM> in response to rotation of drive shaft <NUM>. Drive shaft <NUM> extends from impeller <NUM> within annular volume <NUM> to into shaft chamber <NUM> within housing <NUM>. Shaft chamber <NUM> is defined by sidewall <NUM> extending between end wall <NUM> and bearing 114B rotatably connecting drive shaft <NUM> to housing <NUM>. Drive shaft <NUM> is sealed to sidewall <NUM> by radial shaft seal <NUM> within shaft chamber <NUM> thereby dividing shaft chamber <NUM> into first volume 120A between end wall <NUM> and radial shaft seal <NUM> and second volume 120B between bearing 114B and radial shaft seal <NUM>. First port <NUM> is coupled in fluid communication directly between high fluid-pressure region <NUM> of channel <NUM> and second volume 120B for venting fluid directly from high fluid-pressure region <NUM> of channel <NUM> to into second volume 120B. Second port <NUM> is coupled in fluid communication directly between second volume 120B and low fluid-pressure region <NUM> of channel <NUM> for venting fluid directly from second volume 120B to into low fluid-pressure region <NUM> of channel <NUM>. First volume 120A is larger than second volume 120B.

Claim 1:
A regenerative blower-compressor, comprising:
an impeller (<NUM>) mounted to a drive shaft (<NUM>) within a housing (<NUM>) including a channel (<NUM>) extending from an inlet (<NUM>) adjacent to a low fluid-pressure region (<NUM>) of the channel (<NUM>) to an outlet (<NUM>) adjacent to a high fluid-pressure region (<NUM>) of the channel (<NUM>), the impeller (<NUM>) extends radially outward through an annular volume (<NUM>) within the housing (<NUM>) from the drive shaft (<NUM>) to blades (<NUM>) in the channel (<NUM>), the impeller (<NUM>) is configured to rotate for rotating the blades (<NUM>) through the channel (<NUM>) for forcing fluid through the channel (<NUM>) from the inlet (<NUM>) to the outlet (<NUM>) in response to rotation of the drive shaft (<NUM>), the drive shaft (<NUM>) extends from the impeller (<NUM>) within the annular volume (<NUM>) into a shaft chamber (<NUM>) within the housing (<NUM>), the shaft chamber (<NUM>) is defined by a sidewall (<NUM>) extending between an end wall (<NUM>) and a bearing (114B) rotatably connecting the drive shaft (<NUM>) to the housing (<NUM>), and the drive shaft (<NUM>) is sealed to the sidewall (<NUM>) by a radial shaft seal (<NUM>) within the shaft chamber (<NUM>) characterized in that the shaft seal (<NUM>) divides the shaft chamber (<NUM>) into a first volume (120A) between the end wall (<NUM>) and the radial shaft seal (<NUM>) and a second volume (120B) between the bearing (114B) and the radial shaft seal (<NUM>);
a first port (<NUM>) is coupled in fluid communication directly between the high fluid-pressure region (<NUM>) of the channel (<NUM>) and the first volume (120A) for venting fluid directly from the high fluid-pressure region (<NUM>) of the channel (<NUM>) to the first volume (120A); and
a second port (<NUM>) is coupled in fluid communication directly between the first volume (120A) and the low fluid-pressure region (<NUM>) of the channel (<NUM>) for venting fluid directly from the first volume (120A) to into the low fluid-pressure region (<NUM>) of the channel (<NUM>).