Patent Grant
7018513
1. Technical Field
The invention relates to a device, system, and method, for use with a rotary joint and heat transfer cylinders used typically in the papermaking process. Generally, the device, a secondary bearing support, and a stationary siphon system which may employ it, improves the reliability and efficiency of various papermaking machines.
2. Related Art
A papermaking machine typically includes three main sections: Forming, Pressing and Drying. The raw material, called furnish, is largely water, and is converted to a sheet by these three sections. The first section, Forming, uses vacuum and other means to remove most of the water. At the same time, the fibers of the sheet are formed into the desired mat. The second section, Pressing, removes more water by pressing the sheet between felted rolls. The final phase of removing water from a sheet in a paper machine relies on heated cylinders, called dryers. The Drying frequently consumes more energy than any other section of the machine and, in many cases, more than any other operation in a papermaking mill.
One manner of drying the sheet is to use heated cylinders (a.k.a. dryers or cans). These rotating cylinders are heated by a heat transfer medium, typically this may be steam. A dryer section usually includes of many cans arranged in single or multiple tiers. The sheet is threaded through this arrangement of dryers, wrapping partially around a can and passing from can to can. The sheet is heated by the rotating dryer cans and most or all of the remaining water is evaporated from the sheet.
Several factors determine the rate of evaporation, or drying, of this remaining water within the sheet. One of these factors is the rate of transfer of the heat from the steam inside the dryer can to the exterior surface of the dryer can. As the sheet contacts a dryer, and the steam within the dryer is condensing, heat is transferred from the condensing steam inside the dryer through the dryer shell and into the sheet. A principle of heat transfer is that heat moves from higher temperatures to lower ones. The rate of this transfer depends on the temperature differential and the resistance to the heat transfer. A significant resistance to the transfer of the heat is the quantity of condensed steam, or condensate, inside the can.
A rotary joint, or union, is typically used as a junction point wherein fixed parts of the system meet, or have a junction with, rotating parts of the system. The rotating parts include the can itself and portions of the rotary joint. The fixed parts include other portions of the rotary joint and fixed piping attached to the rotary joint. The steam is supplied to the inside of the can typically through a portion of the rotary joint, or union. In some cases, the condensed steam (i.e., condensate) is evacuated through another portion of the same rotary joint, while in others it is removed through a second rotary joint. Since the condensate collects inside the dryer shell or cylinder, a siphon may be employed to remove the condensate from the shell. The siphon, with its inlet, or pickup, close to the interior surface of the dryer shell, is connected to the rotary joint by a horizontal pipe. The condensate is collected at a tip of the siphon inlet. The condensate then passes into the siphon; then through the horizontal pipe; and, finally through the rotary joint and to the fixed piping connected beyond.
Multiple forces must be overcome to remove the condensate from of the can. This is accomplished, in part, by creating a pressure differential. The pressure differential is typically measured between a steam inlet port leading into the rotary joint and a condensate outlet port, also located on the rotary joint. Optimally, the condensate is removed from the can at the same rate at which it is being created from the condensing steam, while concurrently being done with the lowest possible differential pressure. During normal operating conditions, some steam will also exit the dryer in the same manner as the condensate. This exiting steam is commonly referred to as “blowthrough steam”. Blowthrough steam is undesirable.
Although condensate is being removed from the dryer can, the amount of condensate that remains in the dryer can at any time is determined, in part, by the distance between the siphon tip and the interior surface of the dryer can and the stability of this interface. The closer the siphon tip can be located to the surface of the dryer shell without contacting the shell, the more of the condensate can be removed from inside the dryer, and the smaller the quantity of condensate remains in the bottom of the inside of the dryer. Exacerbating this issue is that siphon tips also move. The siphon tip movement may be caused by movement in several areas including movement in: the rotary joint; the siphon assembly including both the horizontal and vertical pipe portions; the condensate; the rotating dryer can; paper machine vibration; or, a combination of these. Any reduction in this movement permits the siphon tip to maintain its close and consistent proximity with the condensate and to be placed closer to the interior surface of the can, thereby minimizing the amount of the condensate remaining in the can.
The behavior of the condensate inside the can is related to the rotating speed of the can. At very low speeds of rotation, the condensate puddles at the bottom of the can as a result of the forces of gravity. As the speed of rotation increases, however, the combination of centrifugal forces and the adhesion of the condensate to the interior surface of the dryer cylinder causes portions of the condensate puddle to move up the cylinder wall in the same direction as the rotation. This movement of condensate is called “puddling” or “cascading”.
During speeds when the condensate is puddling or cascading, a stationary siphon can be used. The stationary designation results from the fact that the siphon is not rotating along with the can (Cf. other siphon designs, such as rotary siphons, which have a siphon which rotates along with the can). Two beneficial features of the stationary siphon include being able to permanently position the siphon tip close to the condensate puddle, and some stationary siphons may be installed and/or removed without personnel having to enter the dryer cylinder.
Inherent to the process of removing condensate from the can with a siphon, a portion of the supplied steam will also exit. The quantity of this blowthrough steam is determined, in part, by the magnitude of the differential pressure. In part, the amount of differential pressure is dictated by the flow restrictions in the siphon-rotary joint-piping assembly. Thus, the greater the flow restrictions in the assembly, the greater the requisite differential pressure to adequately pull condensate from the can. Unfortunately, the greater the differential pressure is, the greater amount of blowthrough steam that is also removed from the can.
Another deficiency in current stationary siphon systems is mechanical in nature. The entire siphon (i.e., both the horizontal and vertical portions of pipe) frequently is only singularly attached to the interior of the rotary joint at the very end of the horizontal pipe. The siphon may also be supported additionally at a second point close to the aforementioned single point of attachment. These types of siphon connections result in a cantilever of upwards of 50 inches. The cantilever, and the long vertical reach of the vertical portion of the siphon pipe, creates a significant moment arm and resultant stresses on various parts in the rotary joint, including, inter alia, seals and bearings.
In summary, a need exists to overcome the above stated, and other, deficiencies in the art.
It is an advantage of the invention to overcome the above deficiencies in the art.
For example, the present invention provides a stable stationary siphon system that when installed will allow the tip of the siphon to be placed close to the interior wall of the dryer cylinder.
Further, the present invention improves rotary joint life by transferring a portion of the siphon and horizontal pipe loads off of the rotary joint bearings and seals, which are wear parts of the joint.
Also, the present invention reduces the wear and failure of the joint and siphon system by reducing movement of the system in the dryer cylinder.
Also, the present invention improves fluid flow by reducing the movement of the siphon tip relative to the condensate puddle.
Also, the present invention minimizes the resistances to the flow of fluid through the siphon support.
Also, the present invention minimizes the required internal diameter of the dryer journal opening required for optimum fluid flow.
Also, the present invention allows the joint and siphon system to be completely assembled prior to installation in a dryer cylinder.
Also, the present invention can be employed with conventional rotary joint and siphon designs and commercial pipe for the horizontal pipe.
To overcome the aforementioned, and other, deficiencies, the present invention provides a siphon support, a system that employs the support, and method for installing the support
In a first general aspect, the present invention provides an apparatus for use with a rotary joint and siphon comprising:
a siphon support having a first end and a second end, wherein said first end has an internal bearing surface for rotary engagement with said siphon, and wherein said siphon support includes an opening intermediate said first end and said second end for flow of fluid from an interior to an exterior of said siphon support.
In a second general aspect, the present invention provides in a stationary siphon system for rotating heat exchanger rolls having an axis of rotation and a journal concentric to the axis of rotation, said stationary siphon system further includes a rotary joint which includes an inlet port for providing a flow of fluid, said siphon system comprising:
a siphon support with a plurality of openings extending between an exterior and an interior of said siphon support, said plurality of openings adapted to allow said flow of fluid between said rotary joint and an interior of said journal; and
a bearing rotatably attached to said siphon support.
In a third general aspect, the present invention provides a support device adapted for use with a rotary joint and stationary siphon system and rotating heat exchanger rolls having an axis of rotation and a journal concentric to the axis of rotation, wherein said rotary joint has an steam inlet pressure and a condensate outlet pressure wherein a pressure differential is measured between said inlet pressure and said outlet pressure, comprising:
a flow section adapted to receive steam from said rotary joint and transmit steam to said journal, wherein said flow section is further adapted to raise said pressure differential less than about 2 p.s.i.; and
wherein said support device is only attached to a rotatable portion of said rotary joint and to a siphon pipe of said stationary siphon system.
In a fourth general aspect, the present invention provides for use in a stationary siphon system and at least one rotating roll having an axis of rotation comprising:
a hollow support having at least one opening extending between an exterior and an interior thereof, said at least one opening adapted to allow a flow of steam from said interior of the hollow support to an interior of a journal of said rotating roll, wherein a sum of all areas of the at least one opening is defined, AT;
said hollow support being further adapted to allow for a return condensate pipe to pass through said hollow support, wherein D3 is defined as an exterior diameter of said return condensate pipe; and
said hollow support having a first interior diameter, D1, and said hollow support further adapted so that: AT≧π(D12−D32)/4±10%.
In a fifth general aspect, the present invention provides a support device adapted for use with a portion of a papermaking system, said system including a rotary joint, stationary siphon, and rotating heat exchange cylinder, wherein said stationary siphon is solely attached to a stationary portion of said rotary joint thereby creating a cantilever, said support device comprising:
a support point, wherein said support point reduces said cantilever by attaching said stationary siphon at a rotatable portion of said rotary joint; and
said support device is only attached to said stationary siphon and said rotary joint.
In a sixth general aspect, the present invention provides a system for papermaking comprising:
a siphon support having a first end and a second end, wherein said first end has an internal bearing surface for rotary engagement with a siphon, and wherein said siphon support includes an opening intermediate said first end and said second end for flow of fluid from an interior to an exterior of said siphon support; and
a rotary joint operatively attached to said siphon support.
In a seventh general aspect, the present invention provides a system for papermaking comprising:
a siphon support having a first end and a second end, wherein said first end has an internal bearing surface for rotary engagement with a siphon, and wherein said siphon support includes an opening intermediate said first end and said second end for flow of fluid from an interior to an exterior of said siphon support; and
said siphon operatively attached to said siphon support.
In an eighth general aspect, the present invention provides a system for papermaking comprising:
a siphon support having a first end and a second end, wherein said first end has an internal bearing surface for rotary engagement with a siphon, and wherein said siphon support includes an opening intermediate said first end and said second end for flow of fluid from an interior to an exterior of said siphon support;
a rotary joint operatively attached to said siphon support; and
said siphon operatively attached to said siphon support.
In an ninth general aspect, the present invention provides a method of assembly for use with a rotary joint and siphon system comprising:
attaching a siphon support to said rotary joint, wherein said siphon support has a first end and a second end, wherein said first end has an internal bearing surface for rotary engagement with a siphon of said siphon system, and wherein said siphon support includes an opening intermediate said first end and said second end for flow of fluid from an interior to an exterior of said siphon support;
attaching said siphon to said rotary joint; and
placing said siphon through said siphon support.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of embodiments of the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention.
The features of the present invention will best be understood from a detailed description of the invention and an embodiment thereof selected for the purposes of illustration and shown in the accompanying drawings in which:
Although certain preferred embodiments of the present invention will be shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present invention will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of an embodiment. The features and advantages of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings.
As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
Referring now to the drawings,
The sectional view in
The present invention which provides for an improvement for rotary joint and siphon systems is shown in the installed position in
As the sheet (not shown) contacts the exterior surface 41, heat is transferred from the cylinder 40 to the sheet. The steam inside the dryer 40 replenishes the heat transferred to the sheet. As the steam contacts the interior surface 42 of the dryer cylinder 40, it releases heat and eventually becomes a liquid or condensate 100. The condensate 100 is evacuated from the dryer 40 by a siphon 30. As shown in
The entire rotary joint and siphon system, including the siphon support 10 and bearing 20 are shown in the elevational view of FIG. 6 and the sectional elevational view of
The rotary joint 50 may have an internal spider 55, or sleeve, in contact with the horizontal pipe 32. The rotary joint 50 inter alia has a stationary portion 58, a rotating portion 54, one or more bearings 56, and one or more seals 57. The stationary portion 58 of the rotary joint 50 is supported by the bearing 56, which also contacts the rotating portion 54. The seals 57 are also in contact with the stationary portion 58 and the rotating portion 54. Thus, the bearing 56 and the seal 57 are wear parts in the rotary joint 50. With the addition of device 10 and bearing 20 an additional horizontal support point is provided to the siphon 30. As a result, the moment arm created by the cantilever of the siphon 30 and the vertical portion of the siphon 30 is decreased and the resultant stresses on the various wear, and contact, points within the rotary joint 50 are lessened.
A close up elevation sectional view of an embodiment of the invention is shown in detail in FIG. 8.
In order to improve fluid flow (i.e., lessen turbulence, increase or maximize flow, etc.) a pipe system should, inter alia, decrease the quantity of bends in the pipe system, lessen the magnitude of any bends in the pipe system (i.e., decrease the angles in the bends), and avoid narrowing of passageways in the pipe system. Thus, improved fluid flow can be obtained by, for example, avoid having any bends in the pipe system of 90° or more. Conversely, by narrowing passageways resistance is built up against the fluid flow. In the present use, a narrowing of passageways results in an increase in the aforementioned pressure differential. This increase, in turn, has the deleterious effect of increasing the volume of blowthrough steam picked up by the siphon 30. Measured pressure differentials in the art, without the installation of the present invention, typically are of the magnitude of about 3 to 4 psi measured between steam inlet and condensate outlet. The unique shape and configuration of the present invention, when added to a rotary joint and siphon system, does not increase the aforementioned pressure differentials measurably. The invention increases the pressure differential by less than about 2 psi. Thus, an advantage of the present invention, is that the pressure differential remains close to the original range of about 3 to 4 psi. As
AT≧π(D12−D32)/4±10% Equation 1
Thus, the total area of the openings 11 are generally sized to equal, or exceed, the total area of the annular space between the interior surface of the second portion 13 and the exterior surface of the adjacent section of the horizontal pipe 32. An other embodiments of the invention, the device 10 and bearing support 20 together may be sized according to Equation 2, wherein D1 and D2 are referred to in FIG. 3:
AT≧π(D12−D22)/4±10% Equation 2
A method of installation of the present invention is as follows:
A rotary joint and siphon system employing the present invention has an advantage over the prior art of being fully assembled prior to installation into the dryer cylinder 40 . Further, the assembly requires only attachment of the rotary joint 50 to the dryer 40. No additional attachment points of the assembly to exterior or interior parts of the dryer 40 (including the dryer journal 43) are required. This assembly can be accomplished following several procedures. One such procedure is to first attach the horizontal pipe 32 to the rotary joint 50. Most commonly, the rotary joint 50 has a female threaded fitting in the stationary portion 58 of the rotary joint 50. Both ends of the horizontal pipe 32 typically are threaded. One end of the horizontal pipe 32 can be in installed in the female threaded fitting of the rotary joint 50.
Next the siphon support 10 and bearing 20 can be installed. The device 10 and the bearing 20 are fabricated such that the bearing 20 can be inserted into the bore of the first end 14. The device 10 and bearing 20 interface may be lubricated. In alternative embodiments, this interface may be made from materials that do not require lubrication or are self-lubricating.
The bores at the first end 14 and second end 15 in the device 10 allow it to be assembled over the horizontal pipe 32 and positioned next to the rotary joint 50. The siphon support 10 is aligned concentrically with the rotating portion 54 of the rotary joint 50. This alignment can be accomplished by a sleeve of the cylinder portion 13 on the siphon support 10 that fits tightly into the bore on the rotating portion 54 of the rotary joint 50. The attachment of the support 10 to the rotary joint 50 should eliminate any movement between the two parts.
If the method of attachment of the rotary joint 50 to the dryer cylinder 40 involves a tight fitting bore and seat on the dryer journal 43, another manner of alignment is possible. The siphon support 10 may have a small shoulder having the same outer diameter as the end of the rotating portion 54 of the rotary joint 50. When installed, this shoulder will register in the same tight fitting bore and seat at the end of the rotary joint 50. The rotary joint 50 is held firmly to the dryer journal 43 using a flanged arrangement. The shoulder of the siphon support 10 will be firmly sandwiched between the end of the rotary joint 50 and the seat of the dryer journal bore when the flange 53 is tightened. To maintain alignment before installation, a small tight fitting lip (See e.g.,
After the siphon support 10 has been installed on the rotary joint 50 and horizontal pipe 32, the bearing 20 can be installed. The internal bore 21 of the bearing 20 is dimensioned to accept the range of diameters found in commercial pipe. The bearing 20 slides over the end of the horizontal pipe 32 and the smaller external surface 24 of the bearing 20 fits into the siphon support 10. The bearing 20 is fixed in a concentric manner to the horizontal pipe 32. This can be accomplished in many manners. For example, a keyless mounting is possible.
Next a swivel, or hinge joint,33 and brace 34 and the vertical pipe section of the siphon 30 are attached to the free end of the horizontal pipe 32 usually via a threaded connection. The vertical pipe section of the siphon 30 is installed such that it will not rotate about the horizontal pipe 32 and that the siphon tip 31 will be in the desired orientation when the assembly is ultimately installed in the dryer cylinder 40. Note well that the siphon assembly (i.e., 30, 31, 32, 33, 34) shown is only one of several designs that can be installed in a dryer can 40 through the journal 43. For example, other siphon assemblies have different flex joint 33 configurations that those shown, while other assemblies have no brace 34.
Using the internal diameter of the dryer cylinder 40 as a guide, the optimum length of the vertical portion of the siphon 30 in the installed position can be determined. This vertical section of the siphon 30 can be fabricated to this optimum length. This fabrication can be done before or after assembly to the horizontal pipe 32.
With a stationary siphon 30 that incorporates a swivel or hinge 33 at its bending point, the entire rotary joint and siphon assembly (i.e. rotary joint 50, siphon 30 including horizontal pipe 32, and support 10 and bearing 20) can then be installed directly on, and into, a dryer 40. This type of a stationary siphon can be held in a straight alignment for installation. The assembly will assume the bent position after insertion into the dryer 40. The change from the straight position to the bent one may be accomplished by gravity or assisted by springs or other devices.
Properly installed the centerline of the joint and siphon assembly will closely agree with the centerline of the dryer cylinder 40. If this is true, there will be little or no movement of the stationary portion of the siphon 30 when the dryer cylinder 40 is rotating. Additionally, the siphon tip 31 will remain a nearly constant distance from the interior shell wall 42 of the dryer cylinder 40.
The foregoing description of the present 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 disclosed or to the materials in which the form may be embodied, and many modifications and variations are possible in light of the above teaching.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2166245 | Goff et al. | Jul 1939 | A |
| 2934831 | Tasker | May 1960 | A |
| 3946499 | Schiel | Mar 1976 | A |
| 4205457 | Sjostrand | Jun 1980 | A |
| 4691452 | Ferguson | Sep 1987 | A |
| 4792164 | Suemitsu | Dec 1988 | A |
| 5533569 | Reibel et al. | Jul 1996 | A |
| 5864963 | Komulainen | Feb 1999 | A |
| 6203072 | Berghuis et al. | Mar 2001 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 20040182534 A1 | Sep 2004 | US |
