Patent Application
20240175207
This disclosure relates to apparatuses and methods of moving fluid in an axial direction in rotating cylinders, particularly (but without limitation) cylinders used in continuous manufacturing processes in which the cylinders have a heat transfer function. Examples of suitable cylinders are heated dryer drums used in paper manufacturing and cooling cylinders used in spinning metal and/or mineral wool.
Paper products may be made using rotating dryer drums, and metal wool may be made using rotating spinner wheels. While both use rotating hollow cylinders-a dryer drum or the shell of a spinner wheel-their size and function are different. Many conventional dryer drums have a large diameter (usually about 1-3 meters), a length that is multiple times greater than the diameter (usually between about 5-11 meters), operate at rotational speeds of about 300 meters per minute or more, and are used to heat paper web to evaporate water therein. By contrast, many conventional spinner wheels have much smaller diameters (usually between about 50-60 cm), a length that is usually less than the diameter (usually between about 25-35 cm), operate at relatively higher rotational speeds of about 5,000 rotations per minute or more, and may be fully filled with coolant to absorb heat from a shell used to spin threads of molten material. Because of their differences in size and operational conditions, art relating to dryer drums may not be analogous to spinner wheels and art relating to spinner wheels may not be analogous to dryer drums. However, in conventional configurations for both applications, shaft horsepower is generally used to rotate a hollow cylinder, not to move fluid within the cylinder in an axial direction, i.e., from one end or location within the cylinder to another.
Paper Manufacturing. Despite increasing energy costs, and efforts to reduce environmentally harmful emissions therefrom, energy intensive methods of making paper products have remained largely unchanged for more than a century. Drying cellulosic pulp to form paper consumes most of the energy—up to 80% of the total—used by conventional methods of making paper. For example, conventional methods may use more than 1 million joules per pound of water to be evaporated from a paper web. Any improvement that would increase efficiency, even slightly, would result in substantial savings to the industry.
The resistance to heat flow from the steam inside the dryer drum to the paper web consists of a complex conduction system with several layers of thermal resistance. Condensate must be removed from the drum because excess liquid in the drum inhibits heat transfer from the steam inside the drum to the paper web outside. Condensate also requires additional drive power for drum rotation.
For the steam inside a dryer drum, the internal condensate layer is the first major resistance to heat transfer. The level of resistance is subject to multiple factors such as condensate thickness and behavior. During normal steady state operation of the system, condensate is continuously removed, but some condensate is always present inside the drum. As rotational velocities increase to operational levels, centrifugal forces progressively increase on the condensate within the drum until it forms a substantially uniform, annular layer on the inner surface of the drum, a phenomenon called “rimming.” See
To remove condensate from a rotating dryer drum, a siphon may be used. (However, siphons are not generally used in spinner wheels.) In the paper making context, condensate must be moved up through a siphon tube (i.e., away from the inner surface of the cylinder and generally toward a central axis of the cylinder) to the outlet. Rotary siphons, which rotate with the dryer drum, and stationary siphons, which do not, are described in U.S. Pat. No. 5,335,427, issued Aug. 9, 1994, which is hereby incorporated by reference in its entirety.
In conventional configurations, the difference in pressure between a higher-pressure “supply” steam header and lower-pressure “return” condensate header is used to remove the condensate from the cylinder. To further ease its removal, some “supply” steam may be evacuated with the condensate, breaking it up into an aspirated vapor and thereby decreasing its density. The vapor is then carried out as a two-phase flow. (The vapor arises from two sources: (i) supply steam and (ii) condensate flashing into a vapor state due to the pressure drop as it travels through the siphon tube.) The “supply” steam that blows through the cylinder without condensing and giving up its latent heat to the drum system is known as “blow through” steam.
For a conventional dryer drum configuration, significant amounts of “blow through” steam, representing up to 35% or more of total steam, may be required to evacuate the condensate from the rotating dryer drum. For example, rotary siphons, which rotate with the dryer drum and require condensate to overcome centrifugal forces in the siphon shaft, may require up to 35% or more blow through steam. By contrast, because stationary siphons may utilize the relative velocity and momentum of the condensate to help move it up a stationary siphon shaft, they may require less blow through steam than rotary siphon configurations.
Although conventional means exist to promote heat transfer through a rimming condensate later, they principally act by creating turbulence. See, for example, U.S. Pat. No. 4,195,417, issued Apr. 1, 1980, and U.S. Pat. No. 7,673,395, issued Mar. 9, 2010, both of which are hereby incorporated by reference in their entirety, showing plural turbulence bars positioned parallel to the drum's central axis. While such turbulence bars may disrupt a rimming condensate layer as it overtops the bars, they are not pitched at an angle that would tend to move the condensate in an axial direction (e.g., toward the mouth of a siphon for evacuation).
Metal Wool Manufacturing. Spinner wheels may be used to manufacture metal wool and/or mineral wool. Molten material is dripped or applied onto the shell of a fast rotating spinner wheel, creating strands of the “wool” that cool mid-air. The molten material's high temperatures damage the shell of the spinner wheel, which must be regularly replaced at significant expense. Although conventional systems circulate water within a filled cylinder in an attempt to cool them, the cylinder's extremely high rates of rotation (e.g., typically between 5,000 and 6,500 rpm), inhibit circulation near the inner surface of the cylinder and prevent effective convective cooling within the cylinder. Without effective cooling, the cylinders become damaged and must be replaced.
There is a need to utilize shaft horsepower for rotating cylinders to move a fluid in an axial direction within the rotating cylinder. Nonlimiting examples of a suitable cylinder include a dryer drum and a spinner wheel shell. In the paper manufacturing context, a significant amount of energy is lost because of blow through steam requirements ranging from 10-35% of the total steam delivered to the system. Accordingly, if steam could be used almost exclusively for drying paper pulp, instead of moving and removing condensate, up to 35% of energy savings could be realized. Likewise, for wool spinning applications, if water could be moved and circulated more efficiently within a cooling cylinder, greater convection could prevent damage from molten metals, significantly reducing shell replacement costs.
In one embodiment of the invention, a helical blade may be positioned on the inner surface of a cylinder such that the blade rotates with the cylinder. The blade may follow a spiral path having a central axis and one or more loops. The central axis of the spiral path may be collinear with a central axis of the cylinder. In some forms of the invention, the blade may be formed as one or more grooves in the inner surface of the cylinder wall itself or be comprised of plural, non-unitary structures that effectively act as a blade for moving fluid in an axial direction within the cylinder. Some embodiments may comprise plural blades, either at least in parallel or end-to-end.
A helical blade preferably has at least a portion of the blade with a pitch with respect to its central axis greater than 0 degrees and more preferably greater than 3 degrees and even more preferably greater than 5 degrees. To maximize axial movement of the fluid within a rotating cylinder, optimizing the blade pitch and position in the cylinder depends on several factors that depend on the implementation. Some factors include: the size and shape of the cylinder, the fluid's centripetal acceleration, viscosity, and specific gravity, and net pressure differential between the fluid inlet and outlet of the cylinder.
In some embodiments, the pitch may vary, i.e., may be different at different points, along the length of the blade. For example, a first portion of the blade (e.g., proximate to a first end of the cylinder) may have a first pitch with respect to the central axis (e.g., about 70 degrees, 80 degrees or substantially perpendicular to the central axis, i.e., about 90 degrees, or any subrange). A second portion of the blade (e.g., proximate to a second end of the cylinder) may have a second pitch that may be different than the first pitch (e.g., about 60 degrees, about 45 degrees, or substantially parallel, i.e., about 0 degrees, or any subrange).
In some embodiments, a portion of the blade between first and second points may have a pitch that varies along the length of the blade. For example, in one embodiment comprising a blade with a varying pitch, the blade's pitch at a third point between the first and second points may be different than the pitches at the first and second points. In another example, a portion of the blade at one end may have a first pitch of about 90 degrees, a second pitch at the other end of about 0 degrees, and a pitch of about 45 degrees midway between the two ends. In other words, if the interior of a hollow cylinder was hypothetically separated into six zones having an equal axial length, a blade positioned on the inner surface of the cylinder may have at least a portion of the blade in each zone with the following linearly varying pitches: 90 degrees, 72 degrees, 54 degrees, 36 degrees, 18 degrees, and 0 degrees. Pitches may vary linearly, as in the foregoing example, or non-linearly. Numerous alternative varying pitch configurations are possible, however, ranging from 90 to 0 degrees and all subranges between them.
In addition or alternatively, at least a portion of the blade may have a uniform pitch that does not vary in the axial direction. (See, e.g.,
As the cylinder and blade rotate together, fluid on the inner surface of the cylinder may be channeled along the helical blade in at least a partially axial direction. Generally, the velocity of such fluid may be inversely proportional to the blade's pitch (relative to the central axis). For example, fluid channeled along a portion of a blade with a relatively higher pitch (e.g., 70-90 degrees) may have a lower velocity than fluid channeled along a portion of the blade with a relatively lower pitch (e.g., 70-45 degrees or less). In this example, as fluid is channeled along the blade in the cylinder, the fluid velocity in an axial direction increases, i.e., accelerates, as the pitch of the blade decreases in an axial direction. In some embodiments, the pitch may decrease to zero, becoming substantially parallel with a central axis of the cylinder.
Liquid fluid rimming on the inner surface of a cylinder forms a substantially annular shape. If the fluid is incompressible (e.g., liquid water), the fluid that is incident to, and channeled along, a blade may move at least some of the remaining fluid body in the same axial direction of its flow. In this manner, at least one helical blade may move an entire fluid body in an axial direction, even though the blade may be in contact with only a portion of such fluid body.
An inlet of a siphon may be positioned to maximize the momentum of the fluid to assist with its removal from the cylinder. At sufficient rotational speeds, the kinetic energy of the fluid may assist with overcoming the centrifugal forces within the siphon. In some embodiments, a mouth of a siphon may be positioned proximate to a blade within the cylinder.
Paper Manufacturing. In one embodiment, a helical blade may be positioned on the inner surface of a dryer drum. As the dryer drum and blade rotate, supply steam may condense on the inner surface of the cylinder. Such condensate may be channeled along the helical blade in an at least partially axial direction along the length of the dryer drum. In some embodiments, an inlet of a siphon may be positioned at one end of the blade, and, at sufficient rotational speeds, the total kinetic energy the condensate may assist with overcoming the centrifugal forces within the siphon. This may allow the drive motor rotating the dryer drum to act as a principal means of evacuating condensate, significantly reducing or eliminating the need for blow through steam.
The blade may be sized and shaped to act as a barrier such that the condensate cannot overtop the blade at rimming speeds. In addition or alternatively, at least a portion of the blade may be designed so that condensate overtops the blade. The exact shape of the blade may depend on the system's optimal operating conditions and condensate thickness, but one preferred form is an r-shape.
In one embodiment, one or more variable pitch blades may promote a substantially uniform depth of the condensate layer across the axial length of the cylinder. In the papermaking context, this may enable uniform resistance to heat transfer from supply steam, through the condensate layer and dryer drum itself, and across the width of the external paper web.
In an alternative embodiment, a constant pitch blade (i.e., a blade that is uniform and does not vary in the axial direction) may be used for systems that do not require highly uniform heat transfer or where the system includes other means to handle accumulation of fluid at one end of the cylinder. This is in part because a constant pitch spiral blade may tend to have a non-uniform condensate thickness across the axial length of the cylinder, with a smaller condensate layer thickness at one end of the cylinder (e.g., from which condensate may be drawn) and a greater condensate layer thickness at the other end (e.g., where condensate may be directed, near a siphon outlet), which may lead to a non-uniform heat profile across the external paper web.
Metal Wool Manufacturing. In one embodiment, a helical groove may be formed in the inner surface of a shell of a spinner wheel. The helical groove may follow a spiral path having a central axis and one or more loops. In some embodiments, the shell may be partially filled with any suitable coolant, such as water or ethylene glycol. In other embodiments, the shell may be substantially fully filled. As the shell rotates, fluid may be channeled along the helical groove in an axial direction. In some embodiments, the groove may have a variable pitch. In other embodiments, the groove may have a uniform pitch.
In addition or alternatively, a siphon may be positioned within a spinner wheel. In some embodiments, a stationary siphon may be positioned within a partially filled spinner wheel.
In addition or alternatively, a helical blade may be positioned within a spinner wheel. The helical blade may rotate with the spinner wheel, which may be substantially filled. The helical blade preferably has an outer diameter that may be less than the inner diameter of the shell or cage, if any, whichever is smaller. In some embodiments, the blade may have a variable pitch. In other embodiments, the blade may have a uniform pitch.
In some embodiments, a spinner wheel comprising blades and/or grooves may facilitate heat transfer from the outside of the shell to the coolant. Grooves on the inner surface of the shell increase the surface area exposed to the coolant. In addition or alternatively, a blade may be positioned to contact the inner surface of the shell such that it acts as a conductive heat sink.
The above summary is not intended to describe each illustrated embodiment or every possible implementation. These and other features, aspects, and advantages of the invention that will become better understood with regard to the accompanying drawings, description, and claims.
The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, serve to illustrate exemplary embodiments, forms, and aspects of the invention and to explain principles and advantages thereof:
Apparatus and methods of moving fluid in a rotating cylinder are described. An apparatus embodying features of the present invention is shown in
As shown in
The blade 300 may be formed from any suitable material that can withstand the operating environment within the cylinder 100, such as stainless steel, carbon steel, aluminum, and other corrosion-resistant alloys and polymers. In addition or alternatively, the blade 300 may be formed as a groove 370 in the inner surface of the cylinder 100 itself (see e.g.,
As shown in
By adjusting the pitch of the blade 300, the velocity of the fluid at a given point in the drum may be increased or decreased. Accordingly, alternative embodiments may have more or fewer loops with varying and/or uniform pitches, depending on the length of the cylinder, its diameter, steady-state rotational velocity and centripetal force, viscosity of the fluid, pressure differential between inlet and outlet, and desired axial velocity of condensate at a given point, e.g., proximate to the mouth of a siphon.
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By contrast,
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At steady-state rimming speeds, the force applied by the blade 300 on the condensate may be transmitted throughout the incompressible condensate medium (not shown). In other words, the force of the blade 300 on condensate incident to blade 300 may be transmitted through the rimming condensate medium, causing the entire body of fluid to flow toward the second end 104. Condensate is preferably accelerated in an axial direction by the blade 300 to speeds that may be sufficient to at least enter a rotary siphon 200. In more preferably embodiments, the fluid may have sufficient moment to also overcome centrifugal forces within the siphon 200 using little to no blow through steam, and exit the cylinder 100 through outlet 124.
In some embodiments, a rotary siphon 200 may be preferred because it can be fixedly positioned on or near a terminal end of the blade 300 proximate to the outlet 124. The rotary siphon 200 also allows for a very small gap (less than 8 mm) between the siphon inlet and the inner surface 101 of cylinder 100. This gap may define the thickness of the condensate layer, thereby reducing resistance to heat transfer from the steam to the dryer drum 100.
Turning to
Certain configurations may require blow through steam, but such blow through steam is preferably less than 15% of the supply steam, and more preferably less than 1-10% of the supply steam, and even more preferably less than 0.5-5% of supply steam, introduced into the dryer cylinder.
In other configurations without blow through steam, an end of the blade 300 may form a liquid seal with a siphon 200, i.e., the mouth of the siphon 200 may be substantially submerged in the condensate, enhancing evacuation efficiency and flow monitoring. Because the liquid seal prevents steam from exiting the cylinder through the siphon 200, the steam may be forced to impart substantially all its latent heat of vaporization to the system before condensation and evacuation, allowing further process heating optimization of the steam heating medium.
In the context of manufacturing paper products, the apparatus and methods described herein provide three significant advantages over an unmodified dryer drum or a drum with mere turbulence bars.
First, the need to use blow through steam to remove condensate from the cylinder 100 may be significantly reduced or eliminated. The spiral shape of the blade 300 imparts a force to the condensate in an axial direction and provides the means for moving condensate within the cylinder 100 toward the outlet 124. Thereby the rotation of the cylinder 100 itself may be a principal source of the kinetic energy used for evacuating the condensate.
Second, unlike drums with turbulence bars, pitched blades 300 may accelerate condensate medium to turbulent flow velocities without interrupting its path toward evacuation near the second end 104. This reduces the amount of time condensate resides within the cylinder as well as reduces the heat resistance across the condensate layer.
Third, evacuating a single phase liquid eliminates the need for complex control systems and allows for significantly improved flow measurements. In particular, vapor recompression devices and other components required for recapturing two-phase flows with high levels of blow through steam are highly inefficient. Moreover, most conventional flow measurement technology cannot accurately measure two-phase flow comprising condensate aspirated at a siphon inlet because of widely divergent mass density, specific gravity, and velocity profiles associated with such media. A single phase liquid, by contrast, allows for highly accurate flow control, differential pressure control, and quantitative measurements using relatively inexpensive, conventional devices.
However, not all embodiments are required to have any or all the foregoing advantages.
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In addition or alternatively, embodiments with two or more blades 300, 301 may have one blade with more or fewer loops than the other blade or the same or different pitch profile.
At each successive segment, the velocity of condensate entering the segment may be progressively greater than the previous segment and, therefore, the velocity of condensate exiting each segment may be progressively greater. For example, the axial velocity of condensate may be approximately nil at the first loop of segment 310 proximate to first end 102. Condensate may then accelerate across the first segment 310 before entering the second segment 311 and then further accelerated before entering the third segment 312. Accordingly, use of plural segments may allow progressively higher condensate flow velocities along the longitudinal axis of the cylinder toward the end 104 of the cylinder. In some embodiments, a blade 300 comprising plural segments (e.g., as shown in
Apparatuses embodying features of the present invention suitable for spinner wheels are shown in
In operation, the wheel 150 may be at least partially filled with a coolant (not shown) and spun by a motor shaft 153 at high rotational speeds (e.g., 4,000 to 7,000 rotations per minute and any subrange between). In one application, molten metal may be dripped or poured onto the outer surface 1705 of the shell 170, and, on impact with the outer surface 1705, the metal elongates to become thin strands of metal, also known as “mineral wool” or “metal wool.” Without adequate cooling, the shell 170 may become damaged and must be replaced.
Turing to
Turning to
A cavity 165 may be defined by the shell 170 and inner and outer endcaps 175, 1751. Cage 160 is positioned within the cavity 165, forming a gap 1655 between the outer diameter of the cage 160 and the inner surface 171 of the shell 170.
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Turning to
As shown in
In some embodiments, the shoe 184 is positioned with a small clearance (between about 3-6 mm or any subrange between) between the mouth 185 and the inner diameter of the cage 160. Therefore, most of the volume of coolant within the wheel 150 resides in gap 1655 between the cage 160 and the inner surface 171 of the shell 170 (see
Returning to
In these and other embodiments, one or more helical grooves 370 may be configured to impart a force to move fluid from either or both first and second ends 172, 174 toward the siphon 180 and more preferably to its mouth 185 (see
In addition or alternatively, all or a portion of one or more grooves 370 may have a pitch with respect to a central axis 190 such that it has a uniform pitch or a varying pitch. Alternatively, a shell 170 may neither comprise a blade nor groove 370 on or in its inner surface 171.
Turning to
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A cavity 165 within the wheel 150 may be defined by an outer endcap 175, an inner endcap 1751, and an inner surface 171 of the shell 170. For embodiments comprising a cage 160, the cavity 165 may be formed in part by a gap 1655 between the outer diameter of the cage 160 and the inner surface 171 of the shell 170. The cavity 165 and/or gap 1655 may be partially or substantially fully filled with fluid.
Viewing
Fluid may circulate through wheel 150 in either a partially or substantially fully filled configuration. Returning to
The embodiment of the helical blade 375 shown in
Turing to
Turning to
In preferred embodiments, the outer diameter of the blade 375 is in contact with the inner surface 171 of the shell 170, and the blade 375 comprises a material suitable (such as stainless steel) for conducting heat from the shell 170. In this manner, the blade 375 may act as a heat sink for the shell 170. The surface area of the blade 375 that is exposed to the coolant is preferably significantly greater than the surface area of the inner surface 171 of the shell 170.
In some embodiments, the blade 375 may be fixedly attached to the inner surface 171 of the shell 170 by welding or other coupling means. In addition or alternatively, the inner diameter of the blade 375 may be approximately sized to the outer diameter of the hub 168 such that fluid flowing from the inlet aperture 1682 must travel through the helical blade 375 to reach the outlet aperture 1687. In alternative embodiments, a gap (not shown), allowing fluid to flow around the blade 375, may be between either the inner diameter of the blade 375 and the outer diameter of the hub 168 and/or the outer diameter of the blade 375 and the inner surface 171 of the shell 170. For example, in one embodiment, the blade 375 may be coupled to the inner surface 171 of the shell 170 (or a cage 160) and there may be a gap (not shown) allowing fluid to flow between the inner diameter of the blade 375 and the outer diameter of hub 168. In an alternative embodiment, the blade 375 may be coupled to outer dimeter of the hub 168 and there may be a gap (not shown) allow fluid to flow between the outer diameter of the blade 375 and the inner surface 171 of the shell 170.
Viewing
In some embodiments, the cavity 165 may be partially filled with coolant such that less than 80% or 70% or 60% or 50% or 40% or 30% or 20% or 10% or 5% or 1% of its volume is filled with coolant. In alternative embodiments, the cavity 165 may be substantially fully filled with coolant such that more than 80% or 85% or 90% or 95% or 99% and up to 100% of its volume is filled with coolant. (To maintain fluid communication with the fluid, an outlet aperture 1687 may be designed within a hub 168 to be more or less proximate to the inner surface 171 of the shell 170 than is shown in
The blades shown in
As shown in
Turning to
At least a portion of the circumferential outer surface of wheel 170 may comprise any material suitably resistant to heat damage, such as metal or ceramic. The wheel 170 may further comprise material permitting heat transfer from its outer surface 1705 to its inner surface 171.
In the context of spinner wheels 150, the apparatus and methods described herein provide several significant advantages over an unmodified wheel.
First, for a spinner wheel 150 comprising a groove 370 and/or blade 375 and a cavity 165 that is partially or substantially fully filled with fluid, the groove 370 and/or blade 375 may promote significantly enhanced fluid circulation within the wheel 150.
Second, in addition or alternatively, fluid circulation may be enhanced by forcing fluid to travel from a first end 172 of the wheel 150 to a second end 174 of the wheel 150. For example, as shown in
Third, a wheel 150 comprising a siphon 180 may also promote fluid circulation and/or significantly reduce the volume of fluid needed to circulate within the cavity 165.
The first, second, and/or third advantages may apply even if the spinner wheel 150 is not exposed to high temperatures.
Fourth, for a spinner wheel 150 used to spin metal or other molten materials applied to the outer surface 1705 of a shell 170, a groove 370 and/or blade 375 may facilitate heat transfer from the shell 170 to a coolant. For example, the groove 370 may increase the surface area of the inner surface 171 to which the coolant is exposed. In addition or alternatively, the blade 375 may conduct heat from the shell 170, acting as a heat sink.
However, not all embodiments are required to have any or all the foregoing advantages.
Numerous industrial applications for the invention are possible. Any designer of a pipe or cylindrical system in which fluid must be moved in an axial direction may benefit from the teachings of this disclosure. Specifically, whether a process requires a rotating cylinder to be heated or cooled, the invention is directly applicable. Typical examples are dryer drums, “Yankee” tissue dryer cylinders, metal spinning drums, mineral wool spinning wheels, textile slashers, corrugator cans, calendar rolls, water tube boiler tubes, and condenser tubs, among others. Some specific examples of the invention are as follows.
Viewing
The blade pitch may be optimized according to the operating rotational velocity of the cylinder. Based on the foregoing preferred operating conditions, the first loop proximate to the first end 102 forms a pitch with the central axis 190 that is substantially perpendicular. The second pitch 1310 (approximately 83 degrees) and successive pitches 1312 (approximately 72 degrees), 1314 (approximately 58 degrees), 1316 (approximately 35 degrees), 1318 (approximately 14 degrees) have progressively smaller slopes until the end of the blade 300 is substantially perpendicular with the central axis 190. Accordingly, the distance 1320 (approximately 15 cm) between the first spiral and the second spiral may be less than the distance 1322 (approximately 25 cm) between the second and third spirals, which is less than the distance 1324 (approximately 64 cm) between the third and fourth spirals. Likewise, the distance 1326 (approximately 209 cm) between the fourth and fifth spirals may be greater than the distance 1324 but less than the distance 1328 (approximately 323 cm) between the fifth and sixth spirals.
The velocity of the condensate within the cylinder 100 accelerates along the longitudinal axis of the cylinder 100. For condensate contacting the first loop proximate to the first end 102 of the cylinder 100, the velocity is almost zero while condensate proximate to the second end 104 is approximately 1.1 m/s. In some siphon configurations, this may allow the condensate to be evacuated through a rotating siphon with little or no blow through steam.
Cylinder 100 in a paper making machine may have a diameter of about 1.52 meters and a length of about 9 meters. In operation, supply steam pressure may be 860 kpa with a flow rate of 9.1 liters per minute. At steady state conditions, the cylinder may be rotated at 96 RPM. The velocity of the condensate within the cylinder 100 accelerates along the longitudinal axis of the cylinder 100. For condensate contacting the first loop proximate to the first end 102 of the cylinder 100, the velocity is almost zero. In this example, condensate proximate to the second end 104 is approximately 0.78 m/s. In some siphon configurations, this may allow the condensate to be evacuated through a rotating siphon with less than about 10% blow through steam.
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In conclusion, the embodiments and examples shown in the drawings and described above are exemplary of numerous others that may be made within the scope of the appended claims. It is contemplated that numerous other configurations may be used, and the material of each component may be selected from numerous materials other than those specifically disclosed.
In conclusion, in the interest of clarity, not all features of an actual implementation—e.g., dimensions, tolerances, etc.—are described in this disclosure. As used in this disclosure, the terms “about,” “approximately,” and “substantially” apply to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In other words, such words of approximation refer to a condition or measurement that would be understood to not necessarily be absolute or perfect but considered close enough by those of ordinary skill in the art to warrant designating the condition as being present or the measurement being satisfied. For example, a numerical value or measurement modified by a word of approximation may vary from the stated value by 1, 2, 3, 4, 5, 6, 7, 10, 12, and up to 15%.
It will be appreciated that, in the development of a product or method embodying the invention, the developer must make numerous implementation-specific decisions to achieve the developer's specific goals, such as compliance with manufacturing and business-related constraints, that will vary from one implementation to another. Moreover, it will be appreciated that such a development effort may be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. For example, an embodiment comprising a singular element does not disclaim plural embodiments; i.e., the indefinite articles “a” and “an” carry either a singular or plural meaning and a later reference to the same element reflects the same potential plurality. A structural element that is embodied by a single component or unitary structure may be composed of multiple components. Ordinal designations (first, second, third, etc.) merely serve as a shorthand reference for different components and do not denote any sequential, spatial, or positional relationship between them.
The foregoing description of the embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form(s) disclosed, and modifications, and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined only by the following claims, as amended, and their equivalents.
This application is a continuation of U.S. application Ser. No. 17/582,840, filed on Jan. 24, 2022, which is a continuation of U.S. application Ser. No. 16/098,630, filed on Nov. 2, 2018, which is a national stage entry of International Application No. PCT/US17/30600, filed on May 2, 2017, which claims the benefit of U.S. Provisional Application No. 62/331,246, filed May 3, 2016, all of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62331246 | May 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17582840 | Jan 2022 | US |
| Child | 18435856 | US | |
| Parent | 16098630 | Nov 2018 | US |
| Child | 17582840 | US |
