FIELD

The present disclosure relates to shoes used to remove condensate from a rotating process vessel.

BACKGROUND

The background information herein below relates to the present disclosure but is not necessarily prior art.

Conventional drying machines utilize a condensate pickup shoe attached to an end of a siphon which extracts condensate built up inside the cylinder of the drying machine. The shoe is typically attached to a holder and the holder is fastened to the siphon pipe. The shape of the shoe is typically a flat face at the condensate inlet area inside the cylinder. The condensate rim hitting on this flat face causes high drag forces which pushes the shoe in a backward direction. Moreover, there is a low pressure zone formed at the trailing edge of the shoe which also causes a pull in the same direction as the drag force mentioned before. As the shoe is supported by the siphon, these drag forces causes a bending and twisting force in the siphon, thus resulting in the breakage of the siphon at high speeds of rotation of the cylinder. Another force experienced in a shoe is due the sudden change of direction of the condensate when it flows into the siphon pipe. This force is similar to the force experienced by a turbine impeller and at times has a very large component that pulls the siphon pipe downwards. The downward pull causes the siphon pipe to bend and for the shoe to rub on the cylinder inner surface. This reduces the life of the shoe and results in the rupture of siphon pipe. This further results in reduced performance of the shoe in efficiently removing the condensate at a desired flow rate.

There is, therefore, felt a need, for a shoe for condensate removal, and which alleviates the above mentioned drawbacks.

OBJECTS

Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows: An object of the present disclosure is to provide a shoe for condensate removal that efficiently evacuates the condensate at a higher flow rate.

Another object of the present disclosure is to provide a shoe for condensate removal that prevents damage to the siphon pipe carrying the condensate fluid.

Still another object of the present disclosure is to provide a shoe for condensate removal that offers enhanced flow characteristics.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY

The present disclosure envisages a shoe secured to a siphon pipe for removing condensate formed inside a cylinder. The shoe comprises outer side walls extending vertically in a top direction, inner side walls extending vertically in a top direction and at an inclination to the outer side walls. The shoe further comprises a leading bottom edge that is inclined to the front outer side wall and a trailing bottom edge that extends horizontally. The shoe is configured to transport a condensate fluid entering from the leading bottom edge into the inner side walls.

In a preferred embodiment, the inclination of the inner side walls is in the range of 30 to 60 degrees.

In a preferred embodiment, the inclination of the leading bottom edge with the front outer side wall is in the range of 5 to 30 degrees.

In a preferred embodiment, the outer side walls have a curved profile to facilitate streamlining of condensate flow from the leading bottom edge to the trailing bottom edge.

In a preferred embodiment, a first shoe clamp 27 and a second shoe clamp 28 are provided to secure the shoe 31 to the siphon pipe.

In a preferred embodiment, nylock nuts are provided to fasten the shoe to the siphon pipe.

In a preferred embodiment, the shoe is made of polytetrafluoroethylene.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING A shoe for condensate removal of the present disclosure will now be described with the help of the accompanying drawing, in which:

Figure 1 shows an isometric view of a drying machine;

Figure 2 shows a sectional view of the drying machine of the Figure 1 ; Figure 3 shows an isometric view of a shoe of prior art;

Figure 4 shows an isometric view of a shoe, in accordance with an embodiment of the present disclosure;

Figure 5shows another isometric view of the shoe of the Figure 4;

Figure 6 shows a sectional view of the shoe of the Figure 4; Figure 7 shows a detail of the Figure 6; and

Figures 8a-8c show velocity profiles evaluated through Computational Fluid Dynamics (CFD) studies performed on the shoe.

LIST OF REFERENCE NUMERALS USED IN DETAILED DESCRIPTION AND DRAWING 1 stationary steam inlet pipe

2 high speed rotary joint

3 stationary condensate outlet pipe

4 mounting bracket

5 dryer bearing housing 6 dryer cylinder

7 rotary joint cover

8 rotary joint end cap

9 horizontal siphon pipe 10 vertical siphon pipe

11 dryer shaft

12 condensate suction unit

13 condensate rim 14 shoe holder

15 shoe (prior art)

27 shoe clamp 1

28 shoe clamp 2 29 stream lined shoe holder 30 shoe holder clamp

31 shoe (present disclosure)

32 locknuts

33 mlO hexagonal bolts

34 outer sidewalls 34a front outer side wall

35 inner sidewalls

36 leading bottom edge

37 trailing bottom edge

38 condensate entry section 39 condensate guide section

40 condensate pick up section A transverse plane

DETAILED DESCRIPTION

Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.

Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.

Referring to the figures l-8c, a condesate suction unit 12 for condensate removal will be explained in detail. As shown in the figures 1 and 2, a wet paper web is passed over a dryer cylinder 6, which is maintained at high temperature by passing steam therethrough. Rotary joint 2 interfaces components between a stationary inlet steam pipel and the rotating dryer cylinder 6. The steam enters from the stationary steam inlet pipe 1 and passes into the dryer cylinder 6 through the annular area between the horizontal siphon pipe 9 and the dryer shaft 11 bore. When the dryer cylinder 6 rotates along its axis, the thermal energy in the steam gets passed through the inner surface of the dryer cylinder 6 to the paper web passed over the external surface of the cylinder 6. This causes the evaporation of water in the paper web passed over the external surface of the dryer cylinder 6. The surface speeds of dryers vary from 0 to 1200 meters per minute (MPM). When the steam loses energy, condensate is formed inside the dryer cylinder 6, which is evacuated out using the vertical siphon pipe 10. When the dryer cylinder 6 reaches speeds of 250MPM, the condensate starts rotating with the dryer cylinder 6 inner surface, forming a condensate rim 13 due to the centrifugal action of the rotating dryer cylinder 6. A condensate suction unit 12 is provided at the operative bottom end of the vertical siphon pipe lOwhich prevents the end of the siphon pipe from rubbing the inner surface of the dryer cylinder 6, as well as forms a path for the removal of the condensate. The condensate reaches the rotary joint outlet manifold or known as the end cap 8 to finally exit from a stationary steam pipe 3. Condensate removal occurs due to two different reasons: firstly differential pressure maintained between the inlet steam pipe and the outlet condensate line, which is typically in the range of 0.2 bar to 0.4 bar, and secondly the velocity of the condensate rim 13 inside the dryer cylinder 6. Both these factors cause evacuation of the condensate into the shoe 31. The velocity head of the condensate and the inner profile of the condensate suction unit 12 help the condensate to be removed from the dryer cylinder 6.

A streamlined shoe 31 is shown in the figure 4-7 in accordance with an embodiment of the present disclosure. The profile of the shoe 31 has an elliptical outer profile. The shoe 31 is clamped to a shoe holder 29 using a first shoe clamp 27 and a second shoe clamp 28 as shown in the figures 5-7. The first shoe clamp 27 has a plate welded to two threaded protrusions which are put through the shoe 31 as well as the shoe holder 29, and are fastened with a nylock nut 32 on top as shown in the figure 4. The plate remains in the bottom, in a slot, and offers no resistance to the condensate flowing into the shoe. As shown in the figure 7, a chamfer of 10° and 5° at the entry point of the condensate rim 13 allows the condensate to build pressure head at the entry point, as well as give an upward lifting force to the shoe 31. The condensate 13 enters the condensate suction unit 31 as it flows over internal walls that are inclined 30degrees to the horizontal bottom surface of the shoe 31. This facilitates reduction in downward pulling force being acted on the shoe 31 by the condensate 13, as this downward pulling force is caused due to the change in direction of the condensate rim 13 at the entry of the tapered surface of the shoe 13.

The shoe (31) comprises outer side walls (34) and inner side walls (35). The outer side walls (34) extend vertically in a top direction. The inner side walls (35) extend vertically in the top direction but at an inclination to the outer side walls 35.The shoe 31 further comprises a leading bottom edge (36) that is oriented at an inclination to the front outer side wall (34a), and a trailing bottom edge (37) that extends horizontally. The trailing bottom edge (37) has a flat profile. The shoe (31) is configured to transport the condensate fluid entering from the leading bottom edge (36) into said inner side walls (35). In an embodiment, the inclination of the inner side walls (35) is in the range of 30 to 60 degrees. The outer side walls (34) have a curved profile to facilitate streamlining of condennsate flow from the leading bottom edge (36) to the trailing bottom edge (37). The length of the shoe 31 is defined in the direction from the leading bottom edge 36 and the trailing bottom edge 37. The cross section of the shoe 31 is defined to ttaken along a plane A, which is perpendicular to the length of the shoe 31. Thus, the width of the shoe 31 is defined in the direction perpendicular to the length of the shoe 31. The cross section of the shoe 31 is configured to vary along the length of the shoe 31. The cross section of the shoe 31 is configured to be narrow towards the leading bottom edge 36 and the trailing bottom edge 37, while being maximum at the center of the length of the shoe 31.

Figures 8a-8c show velocity profiles evaluated through Computational Fluid Dynamics (CFD) studies performed on the shoe 12. The streamlined profile provides a drag force that is lesser than the conventional shoes that are currently being used. The proposed profile permits more discharge of condensate than the contemporary shoe profiles. Downward forces estimated are also lesser than the contemporary designs. The shoe holder 29 has a clamping arrangement that is parallel to the condensate flow drag force direction. Thereby, the load from the condensate drag force is not subjected on the bolts. The bolts are subjected only to clamping forces and thus likelihood of bolt failures is lessened.

In an embodiment, the condensate enters at the leading bottom edge 36 of a condensate entry section 38 which is inclined at 10° with a horizontal plane to facilitate the smooth entry. A condensate guide section 39 which is inclined at 5° ensures smooth flow of the condensate towards a condensate pick up section 40. The condensate pick up section 40 is inclined at 30° with the horizontal plane which causes a smooth flow of condensate to vertical siphon pipe 10 with minimum reversible vortices. In an embodiment, this optimized configuration of angles ensures maximum smooth flow through vertical syphon pipe 10 and reduces the drag force which is experienced suddenly on the front outer side wall 34a. In addition to above, the optimized angles of condensate entry section 38 and condensate guide section 39 helps to increase the pressure head of condensate flow due to constantly reducing area which increases velocity at the condensate pick up section 40. This results into maximizing the condensate flow in vertical siphon pipe 10, thereby reducing the suction power required by a pump to evacuate the condensate. The power saved is thus 4 to 9 percent, conditional to the rate of condensate generation. As stated earlier the optimized angles of condensate entry section 38 and condensate guide section 39 helps to built the pressure head of condensate flow which further increases the lift force in upward direction. This reduces the chance of the shoe 31 experiencing a downward pull, thereby reducing the possibility of rubbing the inner surface of dryer cylinder 10.

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.

TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a shoe secured to a siphon for condensate removal that:

• has efficient flow characteristics;

• evacuates condenseate at a higher flow rate; and

• prevents damage to the drying machine components.

The foregoing description of the specific embodiments so fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, step, or group of elements, steps, but not the exclusion of any other element, step, or group of elements, or steps. While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.