Method of manufacturing a butterfly valve

The method of manufacturing a butterfly valve from plate steel which comprises flame cutting the outer configuration of the valve body and flame cutting a circular disc from the center of the body resulting in a water opening through the body and utilizing the disc as the closure member. The valve is constructed in such a manner that no castings or welding is required.

This invention pertains in general to butterfly valves and more 
particularly to a butterfly valve wherein no casting or weldments are 
utilized in construction of the valve. 
Conventional valves of the butterfly type employ a disc like closure member 
carried by shaft means such as a through shaft or shaft trunnions 
journalled in the valve body. The disc is movable through 90 degrees 
between a closed position in which the disc extends substantially at right 
angles to the axis of the flow passage and an open position in which the 
disc extends substantially coincident with such axis. 
In the past, it has been the practice to construct butterfly valves of 
castings having axially spaced twin mounting flanges which were bolted to 
the water pipe. An example of such a prior art butterfly valve is shown in 
U.S. Pat. No. 3,532,321 issued to G. K. Bowman et al, Oct. 6, 1970. 
Examples of other prior art butterfly valves are shown in the following 
U.S. Pat. Nos: 2,853,267; 2,946,553 and 3,591,133. Although these patents 
do not specifically state how the butterfly valve is constructed, it has 
been the usual practice in the past to form the valve housing and disc by 
casting or by utilizing welding procedures. 
It is the intention and general object of this invention to construct a 
butterfly valve without utilizing any casting or welding procedure. This 
is accomplished by flame cutting a piece of plate steel into the outside 
configuration of the valve body. The desired water passage opening through 
the valve body is then provided by cutting a circular disc from the center 
of the valve body. This disc is utilized as the closure disc. Both the 
closure disc and valve body are machined and the necessary sealing 
elements are bolted thereto. In this manner, no casting or welding is 
necessary. 
A more specific object of the subject invention is to provide a method for 
manufacturing a butterfly valve from plate steel by flame cutting the 
outside configuration of the valve body and flame cutting a closure disc 
from the center of the valve body to provide the water passageway 
therethrough. 
A more specific object is to provide a method of manufacturing a butterfly 
valve of the hereinbefore described type wherein machining operations are 
provided on the valve body and closure disc to provide mounting space for 
sealing elements attached to each member.

Referring to the drawing, and particularly FIG. 1, a piece of plate steel 
generally designated 6 is shown having the desired composition and 
thickness necessary to withstand the forces which will be imposed upon the 
valve when in operation. A torch generally designated 7 is utilized to cut 
the valve body 8 into the desired outside configuration from the steel 
plate. The torch is also utilized to cut an opening 9 through the central 
portion of the valve body to provide the desired water passageway 
therethrough. The disc 11 which remains after the torch 7 has cut the 
opening 9 is utilized as the closure disc for the valve. As shown herein 
for purposes of illustration, the valve body 8 is provided with a pair of 
oppositely disposed bearing bosses 12 and 13. After the valve body has 
been cut to the desired configuration by the torch 7, the outside surface 
of the body 8 and the inner surface of the opening 9 are ground to the 
desired smoothness. A pair of aligned openings 14 and 16 (FIG. 2) are 
bored through the oppositely disposed bosses 12 and 13. Shaft sleeves 
bearings 17 may be provided in these openings. Each of the openings 14 and 
16 is provided with enlarged bores 18 and 19, respectively, at the outer 
ends thereof. 
An annular counterbore 21 is machined on one side of the body 8 about the 
water opening 9. A plurality of circumferentially spaced water pipe 
mounting holes 22 are drilled and depending on the application may be 
tapped about the outer surface on each side of the valve body 8. In 
certain instances, it may be desirable to stagger the mounting holes 22 on 
opposite sides of the valve body for strength purposes. 
An annular recess 23 is machined on one side of the disc 11 about the 
periphery thereof. A seal ring 24 which may be of stainless steel, 
depending on the application of the butterfly valve is bolted to the disc 
11 by means of a plurality of circumferentially spaced cap screws 26. The 
disc 11 also has a pair of oppositely disposed bores 27 therein which are 
alignable with the shaft openings 14 and 16 in the valve body when the 
disc is located in the operating position within the valve body as shown 
in FIG. 2. 
The valve is assembled by inserting the valve disc 11 with the seal ring 24 
attached within the opening 9 in the valve body. Stubshafts 28 and 30 
extend through the openings 14 and 16 in the valve body into the bores 27 
provided in the valve disc. Pin holes 29 are then bored through the valve 
disc and the associated stubshaft as shown in FIG. 2. One end of these 
holes 29 may be threaded as shown for sealing purposes and pins are then 
passed through these openings to securely attach the disc 11 to the shafts 
28 and 30. A composition seal ring 31 is positioned in the annular 
counterbore 21 to mate with the seal ring 24. The composition seal ring 31 
is held in place by a annular plate 32 which overlies the seal ring 31 and 
is bolted to the valve body by a series of circumferentially spaced cap 
screws 33. 
The stubshaft 28 may be formed with a shoulder thereon or as herein shown 
for purposes of illustration, a collar 34 is connected to one end of the 
shaft 28 by means of a pin 36. This collar is located in the annular 
enlarged opening 18 and a cover plate 37 is bolted to the outer surface of 
the boss 12 to hold the stubshaft in place. This plate, the collar and the 
shoulder formed between the enlarged bore 18 and opening 14 provide axial 
thrust bearing surfaces for the disc 11. 
Conventional shaft packing indicated at 38 is provided about the stubshaft 
30 in the enlarged opening 16 provided in the outer surface of the boss 
13. A valve operator (not shown) is in the conventional manner, connected 
to an extension of the stubshaft 30 to provide the necessary force to 
operate the valve disc 11. 
From the above description, it can be seen that an inexpensive and yet 
highly reliable butterfly valve can be constructed in accordance with this 
invention. In many instances, such as atomic energy applications, it is 
absolutely necessary to insure the mechanical integrity of the valve. When 
castings are utilized, expensive inspection procedures and test methods 
are necessary to insure that the casting does not have dangerous voids 
therein. Furthermore, whenever weldments are used to assemble a valve 
utilized in atomic aplications, the welds have to be carefully examined to 
insure their mechanical integrity. From the above description, it can be 
seen that the butterfly valve of this application does not utilize any 
casting or any weldments and therefore the mechanical integrity can be 
easily verified.