Field of Invention
The present invention generally relates to Globe Valves for high temperature and high pressure applications. More particularly the invention leads to an improved globe valve without welding between body and yoke. Still more particularly the invention relates to improved globe valve having modified components of valve assembly.
Background of the Invention
The company is manufacturing different types of valves to the highest standard for a wide range of critical applications in the power industry, oil and gas sector. The product range includes conventional gate, globe and non-return valve, safety valve etc.
The company is also supplying the Forged High pressure globe valves with welded body and yoke design for various systems like flow discharge line, feed water line (economizer inlet) and spray system in sub critical and super critical boilers. The forged high pressure globe Valves used for high temperature and high pressure applications are very common which are of welded design.
This project leads to an improved globe valve without welding between Body and Yoke. Still more particularly it relates to having modified stem assembly. The valve body is machined for inlet and outlet. In the middle of inlet and outlet boring operation is carried out centrally and stellite deposition is carried out

followed by post weld heat treatment. The machining operation is carried out internally on the stellite deposit portion for desired finish. Now, the yoke is to be welded with valve body.
The valve body is welded with Yoke by means of conventional Tungsten Inert Gas (TIG) welding for root and subsequently followed by Sub-merge Manual Arc Welding (SMAW) process.
This process takes normally 3 shifts per valve. The size of valve ranging from 1/4" to 2" depends upon the pipeline where these valves are used for high temperature and high pressure applications. The above welding process is limited for carbon steel and low alloy steels of grade F22 suited upto 525 deg C. For the temperature range more than 525 deg C, F91 alloy steel materials are used for body and yoke. The welding process is very stringent for F91 alloy materials because of pre-heat, post heat and stress relieving requirements. Moreover, if the defect is found in the welding, repairing takes more time for gouging, grinding, welding and again testing. This leads to more lead time for the assembly.
Combining item body and yoke, the assembly is put inside the furnace for stress relieving process. After the heat treatment is over, the assembly is taken out for visual examination. Sometimes it has been found that, some cracking occurs in the stellite deposition of the valve body. It is ir- repairable and the whole Body and Yoke assembly are thrown to scrap which leads to loss of material and time.

Hence, there is a need to find out a new method of making the valve body and Yoke as one assembly, without involvement of welding and there is also another need to make repairable stellite deposition on the seat area of the valve body. While hydro testing of valve, it is found that leakage occurred due to improper matching of disk retainer and packing bush. Moreover, due to load on the stem the stem collar is also broken out immediately. These problems are also addressed while developing a new method of manufacturing globe valve for the above applications.
Referring to the figure 1, the valve body (01) is machined for inlet and outlet. In the middle of inlet and outlet boring operation is carried out centrally and stellite deposition (16) is carried out on the surface of valve body (01) followed by post weld heat treatment. The machining operation is carried out internally on the stellite deposit portion of valve body (01) and externally on the stellite deposit portion of disc (21) for desired finish. Now, the yoke (04) is to be welded with valve body (01) in the area of body-yoke welding (02) as shown Figure.1. The valve body (01) is welded with Yoke (04) by means of conventional Tungsten Inert Gas (TIG) welding for root and subsequently followed by Sub-merge Manual Arc Welding (SMAW) process. This process takes normally 3 shifts per valve. The size of valve ranging from 1/4" to 2" depends upon the pipeline where these valves are used for high temperature and high pressure applications. The above welding process is limited for carbon steel and low alloy

steels of grade F22 suited upto 525 deg C. For the temperature range more than 525 deg C, F91 alloy steel materials are used for body and yoke. The welding process is very stringent for F91 alloy materials because of pre-heat, post heat and stress relieving requirements. Moreover, if the defect is found in the area of welding (02), then the repairing takes more time for gouging, grinding, welding and again testing. This assembly is put inside the furnace for stress relieving process. After the heat treatment is over, the assembly is taken out for visual examination. Sometimes it has been found that, some cracking occurs in the stellite deposition (16) of the valve body (01). It is ir-repairable and the whole Body (01)-Yoke (04) assembly are thrown to scrap which leads to loss of material and time.
Referring to the figure 2, stem disc assembly consists of following processes, that is, Lapping of stellite deposit portion of disc (21) is done and the thrust plate (20) is placed in the middle of the disc then the stem (05) is inserted on the thrust plate (20) along with disc retainer (18). Disc retainer (18) is well screwed with disc (19) and free rotation of disc (19) on the stem (05) is ensured. Punchingis done on the outer surface of stem disc assembly to ensure the tightness of disc (19) with disc retainer (18). This stem-disc assembly is moved to valve assembly.
In valve assembly, all components and tools are collected for assembly and lapping is carried out on the stellite deposit portion of valve body (16) for

required finish (.8µ) by lapping tool then the packing bush (03) and backseat area of valve body is also lapped for required finish. This leads more time for lapping because irregularities in the surface of backseat area of the valve body is to be leveled by stop facing tool manually. Then the stem-disc assembly (Fig.2) is placed in the middle of the valve body (01) after that packing bush (03) and retainer ring (15) are inserted through the stem-disc and screwed with valve body (01). Tightening of retainer ring is done by pneumatic wrench which requires more man power (3 person) even small range of valve (1/4” to 2”) and also creates more noise in the work place. Stop ring (14), packing cartridge (13), gland follower (11) and gland flange (10) are inserted into the valve body (01) followed by screwing of yoke bush (06) on the top of yoke (04).Then the stud (12) and nut (09) are assembled and tightened with suitable spanner. Finally handle (07) and handle nut (08) are assembled in the top of the stem (05) after that valve is moved to hydro testing. During hydro testing more backseat leakage is observed in the valve (Backseat leakage means Passing/leakage through stuffing box). Hence, the valve is to be reworked by dismantling of all valve components, re-lapping of packing bush, disc retainer and backseat area of valve body, re-assembling of valve and re-testing of valve. Here, Flat backseat area (17) on the stem is one of the main cause for backseat leak during the hydro testing and it is also found that leakage occurred due to improper matching of disk retainer (18) and packing bush (03). Moreover, due to load on the stem (05) the stem collar (22) is also broken out immediately. This leads to more lead time for the assembly and also more process cost of valve.

Hence, there is a need to find out a new method of making the valve body (01) and Yoke (04) as one assembly, without involvement of welding and there is also another need to make repairable stelliting on the seat area of the valve body (01). Hence, these problems are also to be addressed while developing a new method of manufacturing globe valve for the above applications.
Object of the Invention
It is therefore, an object of the invention is to propose a new Globe Valve without welding body and Yoke.
Another object of the invention is to propose a method of making access for repairing stelliting.
A further object of the invention is to propose a new design of stem with a tapered backseat on the stem.
Summary of the Invention.
Accordingly, the valve body is made with internal thread ranging from M50 to M68 depends upon the valve size as shown in the table 1. And the yoke is also made with the internal thread ranging from M50 to M68 depending upon the valve size as shown in the table 2. The bonnet is used as connecting piece between yoke and valve body. Based on the experiments carried out, the optimum size for the bonnet is obtained to connect the valve body and yoke.

Now without welding, we got body and yoke assembly having strength equal to welding of Body and Yoke. Thereby, the whole welding process is eliminated and the drawbacks said in the background are eliminated.
The stem is manufactured with a tapered portion at the bottom side and corresponding matching taper is made in the bonnet so that, while applying pressure on the stem, it won’t affect the collar and hence damage to the stem collar is totally avoided. By introduction of this taper feature on the stem, leads to elimination of backseat leakage totally.
By the introduction of a bonnet in between the body and yoke, interchangeability of different yoke materials is possible, than prescribed in the existing method of manufacturing.


Brief description of the Accompanying drawings.
Figure 1 - shows the sectional views of existing globe valve assembly with all the
part assembled. Figure 2 - shows the sectional view of the existingstem-disc assembly Figure 3 - shows the sectional view of the new type globe valve assembly with all
the part assembled with introduction of bonnet between valve body
and yoke Figure 4 - shows the sectional view of newstem-disc assembly (Detail. A) With
taper introduced on stem. Figure 4A - View A of figure 4 Figure 5 - shows single view of the bonnet (24N) with external threading and
counter boring details. Figure 6 - shows the modified stem (05M) showing the taper backseat area.
Detailed description of the preferred embodiment of the invention
As shown in the figure 3 and 4, now the improved valve assembly consist of the tapered backseat stem (17M), Lock Ring (23N), spiral wound gasket (26N) and bonnet (24N), assembly of the valve is as follows.
Referring figure.3, modified valve body (01M) is a single casting body which is machined for inlet and outlet. In the middle of inlet and outlet boring operation is carried out centrally and stellite deposition on the surface of modified valve body (16M) is carried out followed by machining of satellite deposit portion of modified

valve body (01M) after that the internal threading operation is done in the modified valve body (01M) and internal threading operation is done in the modified yoke (04M) as per the dimension given in the table.1 and table.2 depending upon the size of the valve ranging from 1” to 2”. A bonnet (24N) is introduced for connecting the modified valve body (01M) and modified yoke (04M).
Referring to the Figure 3, Machining operation of bonnet (24N) including external threading to assemble with modified valve body (01M) and modified yoke (04M) and counter boring to accommodate packing cartridge (13M), step turning is carried out to seat spiral wound gasket (26N) and internal taper machining (25N) to match with backseat area of stem (17M) are carried out in the bonnet (24N).
Referring figure.4, new stem-disc assembly consists of the following process, a lock ring (23N) is inserted into slot portion of modified stem (05M) then the modified thrust plate (20M) is placed into the modified disc (19M) after that modified stem (05M) is inserted in the modified disc (19M) along with modified disc retainer (18M) and screwed with modified disc (19M).
In this assembly, stem is made with taper backseat area (17M) which makes line contact with the backseat area of bonnet (25N) to prevent the backseat leakage/passing during the hydro testing of valve. Modifications of design of disc,

disc retainer, Stellite deposition on the disc and thrust plate are made only for standardizing the dimension and improving the design of valve.
In valve assembly, lapping operation of modified valve body (01M) is done for required finish (.8µ) then spiral wound gasket (26N) is inserted in the valve body after that bonnet (24N) is inserted into new stem-disc assembly and screwed with modified valve body (01M), then modified Packing cartridge (13M) is inserted into the bonnet (24N). Modified gland follower (11M) and modified gland flange (10M) are inserted in the modified valve body. After that modified yoke (04M) is screwed with bonnet (24N) and modified yoke bush (06M) is screwed on the top of modified yoke (04M) then modified handle (07M) and handle nut (08M) are assembled. After that modified stud (12M) and nut (09M) are assembled. Modification of design of yoke bush, stud, nut, gland follower, gland flange, handle and handle nut are made only for standardizing the dimension and improving the design of valve.
Earlier body and yoke were welded, but in this process/design, body and yoke are screwed. In addition to this, taper backseat is introduced to avoid backseat leakage. Thus it eliminates the welding process and subsequent operations to the welding. In addition to bonnet, components like stop ring, Packing bush, retainer ring are eliminated in the new type valve assembly.
This not only reduces the process time, but also reduces the number of rejections and increases the productivity.

Thus, as claimed above, the drawbacks said in the background of the invention are totally eliminated which leads to productivity by reduction of cycle time in the manufacturing.
Flow chart for assembly of valve
Lapping these at area of modified valve body (01M)
Assembly of stem-disc (Figure-4)
Inserting the spiral wound gasket (26N) into the body
Screwing the bonnet into modified valve body (01M) along with the stem-disc assembly
Inserting the packing cartridge into the bonnet
Screwing the modified yoke (04M) into the bonnet along with gland follower, gland flange
Assembling the modified yoke bush (06M) in the top of the yoke
Connecting the gland flange, yoke and body with stud & nut
Assembling the handle and handle nut
at the top of stem

Note: Item no. with ‘M’ denotes Modified and ‘N’ denotes New item and few components are eliminated in the new type valve which are indicated in the bold letters.
01-VALVE BODY 01M-MODIFIED VALVE BODY
02-BODY-YOKE WELDING AREA 04M-MODIFIED YOKE
03-PACKING BUSH 05M-MODIFIED STEM
04-YOKE 06M-MODIFIED YOKE BUSH
05-STEM 07M-MODIFIED HANDLE
06-YOKE BUSH 08M-MODIFIED HANDLE NUT
07-HANDLE 09M-MODIFIED NUT
08-HANDLE NUT 10M-MODIFIED GLAND FLANGE
09-NUT 11M-MODIFIED GLAND FOLLOWER
10-GLAND FLANGE 12M-MODIFIED STUD
11-GLAND FOLLOWER 13M-MODIFIED PACKING CARTRIGE
12-STUD 16M-STELLITE DEPOSITION ON THE MODIFIED VALVE BODY
13-PACKING CARTRIGE 17M-TAPER BACKSEAT AREA IN THE STEM
14-STOP RING 18M-MODIFIED DISC RETAINER
15-RETAINER RING 19M-MODIFIED DISC
16-STELLITE DEPOSITION ON THE VALVE 20M-MODIFIED THRUST PLATE
BODY
17-FLAT BACKSEAT AREA IN THE STEM 21M-STELLITE DEPOSITION ON THE MODIFIED DISC
18-DISC RETAINER 23N-LOCK RING
19-DISC 24N- BONNET
20-THRUST PLATE 25N- TAPER BACKSEAT AREA OF BONNET
21-STELLITE DEPOSITION ON THE DISC 26N- SPIRAL WOUND GASKET
22-STEM COLLAR

We claim
1. New type of high temperature, high pressure application of globe valves without welding body and yoke comprising:
- a modified valve body (01M) having an inlet and outlet; the said valve body (01M) being bored centrally for stellite deposition on the surface (16M);
- the distal end of the valve body (01M) having internal thread;
- the said internal thread of the valve body (01M) fits into the external thread of a component bonnet (24N) at the first end of the intermediate space between bonnet (24N) and the modified valve body (01M) seat being filled by spiral wound gasket (26N);
- the second end of the bonnet (24N) also having external thread that fits with the internal thread of modified yoke (04M);
- the assembly being placed centrally around the central axis of a modified stem (05M);
- the modified stem (05M) having taper backseat area (17M);
- the bottom end of the stem (05M) placed within modified disc (19M) with modified disc retainer (18M), lock ring (23N) and modified thrust plate (20M) in between for gripping the joint tightly;

- the lower end of the modified disc (19M) having stellite deposition (21M), the arrangement having the stem (05M) with backseat area (17M) which makes line contact with the taper backseat area (25N) of bonnet to prevent the backseat leakage passing during hydro-testing of valve, which replaced the weak welding joint (02) between the modified valve body (01) and original yoke (4).