Metal working – Method of mechanical manufacture – Valve or choke making
Reexamination Certificate
1999-03-05
2001-02-13
Cuda, I (Department: 3726)
Metal working
Method of mechanical manufacture
Valve or choke making
Reexamination Certificate
active
06185821
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
The invention herein relates to a practical forged flange-type ball valve fabrication method that references blueprints of conventional flange-type valves to determine the appropriate position at the neck sections to delineate the separation needed to initially forge the water inlet seat and the ball valve seat of a one-piece flange-type ball valve or to initially forge the water inlet seat, the ball valve seat, the position limiter seat, and the water outlet seat of a two-piece flange-type ball valve. Then, friction welding is utilized to unite the welding surfaces of the water inlet seat and the ball valve seat into a structurally unitary one-piece flange-type valve or, in the case of the two-piece flange-type valve, the water inlet seat is welded to the water inlet seat and the position limiter seat is welded to the water outlet seat to form the left and right primary elements, of which all the center through-holes in the said forged components have already been formed in the same fabrication process to save material costs, shorten fabrication time, and reduce the detect rate.
2) Description of the Prior Art
Nearly all conventional metal ball valves are fabricated into shape by casting techniques because the left and right primary elements can be cast as a single physical entity and, furthermore, most of the interior and exterior features of the said initial blanks are already formed after being cast into shape and only require the finishing and drilling of various sections to complete the valve. However, cavitation readily occurs during the casting process and to lessen the fine surface pitting resulting from the said cavitation, the initial blanks are given additional thickness and then the actual thickness required is achieved by interior and exterior finishing. While this reduces fine pitting, the material removed constitutes an enormous waste and, furthermore, the complete elimination of the said pitting is not possible. As a result, defect rates tend to increase and defective products that are marketed may leak. Soldering or welding during maintenance could unavoidably result in explosions or fires, which are common disasters often observed.
Due to the said shortcomings of ball valves that are fabricated by casting, the industry expected to avoid pitting flaws by forging the valve blocks. Referring to
FIGS. 1A and 1B
, the initial blank of a forged two-piece flange-type valve of typical manufacture achieved the objective of single-entity shaping but still utilizes horizontal forging technology to forge the left and right primary elements A
1
and A
2
. Because of the limitations on easily opening the dies after forming, a die removal angle had to be included inside the die which left a vertically oriented border on the left and right primary elements A
1
and A
2
that was manifested in the die release angles A
11
and A
21
that facilitated the opening of the die and, furthermore, the required center through-holes A
12
and A
22
as well as the ball valve chamber A
13
of the left and right primary elements A
1
and A
2
could not be formed at the same time. The left and right primary elements A
1
and A
2
were solid blanks that still required shaping to become a ball valve, for example, the area indicated by the invisible line in the left and right primary elements A
1
and A
2
must be removed and, therefore, additional material has to be utilized in the said shape and forging must be followed by several stages of difficult finishing, which involves the waste of material. As such, although forging was expected to solve the shortcomings of casting such as high material and finishing costs, the cost remained high, the product did not impress users and could not be successfully promoted to consumers because improvement was still necessary.
Furthermore, referring to
FIG. 1C
, the one-piece flange-type ball valve C is forged as a single structural entity, but is still in a solid state. The die removal angle C
1
is unavoidable and, furthermore, the interior center through-hole C
2
and the ball valve chamber C
3
must be machined out, which requires the removal of the sections indicated by the invisible line C
1
. Referring to
FIG. 1D
, to position the ball valve D in the ball valve chamber C
3
, the external threads C
41
of the plug C
4
must be screwed to the internal threads C
21
along the right side of the center through-hole C
2
so the plug C
4
can be brought against the curvature of the ball valve. The plug C
4
is indispensable in the structure of the one-piece flange-type ball valve and since the exterior shaping and finishing of the plug C
4
is easy to complete, the inventor will continue utilizing this aspect of the structure. However, the internal finishing of the unitarily forged conventional one-piece flange-type ball valve involves a high degree of difficulty, which increases the finishing time, wastes material, and is essentially impractical.
Therefore, in view of the said shortcomings, the inventor of the invention herein addressed the said drawbacks by conducting research based on many years of production experience with efforts finally culminated in the research and development of the invention herein which is hereby submitted in application for the granting of the commensurate patent rights.
SUMMARY OF THE INVENTION
The primary objective of the invention herein is to provide a practical forged flange-type ball valve fabrication method for forging the left and right primary elements that are separated at the neck sections to comprise a one-piece flange-type ball valve or a two-piece flange-type ball valve, with the process including the direct forging of the water inlet seat and the ball valve seat for a one-piece flange-type ball valve the forging of the left primary element to form the initial blanks of the water inlet seat, the ball valve seat, and the forging of the right primary element to form the initial blanks of the position limiter seat and the water outlet seat, thereby enabling the fabrication of all the center through-holes and ball valve chamber in a single process without requiring the machining of the interior sections. Following this, all welding surfaces are brought flush and united utilizing friction welding methods to enable the welding of the water inlet seat to the ball valve seat of the one-piece flange-type valve as though the valve was fabricated entirely by forging and, furthermore, the welding together of the left and right primary elements of the two-piece flange-type ball valve to achieve the same forged fabricated appearance. All welding beads in the center through-holes are machined off utilizing a lathe to achieve a smooth surface in the center through-holes and the welding beads along the neck sections are removed during the surface finishing process, which thereby enables the saving of material costs and shortens the fabrication time, but retains the original strength of forging.
Another objective of the invention herein is to provide an emergency leakage structure, of which the bottom end of the ball valve seat in the said two-piece flange-type ball valve is machined into an inverted angle left sealing ring and the front end of the right primary element position limiter seat is machined into an inverted angle right sealing ring, such that when there is leakage of a hazardous gas or liquid, the bolts of left and right primary elements can be tightened to bring the left and right sealing rings into contact against the curved surface the ball valve seat as a temporary measure to stop the leakage until all liquid and gas content in the pipeline is expelled, at which time repair or replacement can be conducted. Furthermore, such a design prevents hazardous situations and reduces liquid and gas losses.
The fabrication method of the invention herein is further elaborated in the brief description of the drawings below which is followed by the detailed description of the invention herein.
REFERENCES:
patent: 3841601 (1974-10-01), Grove et al.
patent: 3869108 (19
Cuda I
Dougherty & Troxell
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