We manufacture more than a thousand specifications of over ten series of products, including safety valves, power station valves, steam extraction check valves, gate valves, globe valves, check valves, hard-sealed ball valves, all-welded ball valves, ball valves, butterfly valves, and other models and specifications.
DN700
Cylindrical fixed full-welded ball valve
Product Classification:
Key words:
Overview
Fixed Ball Structure: The fixed ball structure has upper and lower rotating shafts. The lower part of the ball is embedded with bearings and fixed by the lower valve stem, while the upper part is connected to the upper valve stem. The ball can only rotate along the vertical axis of the valve passage and cannot move to one side like a floating ball valve. Therefore, when the fixed ball valve is working, the pressure of the fluid before the valve and the spring force push the valve seat to tightly press the ball, forming a reliable pre-valve seal. The fixed ball valve has a DBB function, which means that the valve can simultaneously cut off the medium upstream and downstream of the pipeline, and the valve sealing is safe and reliable.
Product Features
• Low flow resistance coefficient
The pressure loss of the ball valve at the nominal flow rate is the smallest among all valve types, equivalent to the flow resistance coefficient of a pipe of the same length, which is almost zero; our company's reduced diameter ball valve has been analyzed and theoretically calculated by fluid mechanics, and the flow channel design maximizes the valve's flow capacity and reduces the flow resistance generated by the reduced diameter part.
• Bidirectional sealing
The ball valve is not affected by the direction of the fluid medium. Either end of the valve can be used as the upstream end, and the fixed ball valve can simultaneously cut off the fluid medium from upstream and downstream.
• Good sealing performance
Double valve seat and bidirectional sealing. The valve seat seal is composed of VITONB+ (suitable for different pressure levels) non-metallic polymer + hard seal, ensuring that the ball valve can achieve bubble-level sealing (i.e., zero leakage) under different pressure differences, with safe and reliable sealing.
• Long service life
The non-metallic sealing surface has good lubricity and low friction and wear with the ball. The multi-stage sealing structure, combined with the spring pre-tightening force, makes the sealing safe and reliable, thereby improving the service life of the ball valve.
Product Installation
1. The pipelines connected to the valve should be thoroughly cleaned to avoid iron filings, mud, welding slag, and other debris from damaging the valve sealing surface.
2. This series of ball valves can be installed in any position, and either end of the valve can be used as the upstream end. Both horizontal and vertical installation are possible, but reverse installation is prohibited to prevent valve stem corrosion;
3. During installation, the valve should be kept fully open (adjusted to the position at the factory), otherwise it may cause damage to the valve; Warning: Do not leave the valve half-open or half-closed.
4. After the center of the valve is aligned with the center of the pipe and pipeline, welding installation can be carried out:
5. Welding connections should be constructed according to welding procedures that have passed welding process qualification, and during installation welding, prevent welding slag and weld beads from entering the valve cavity and damaging the sealing surface. During installation, the valve should be in the fully open position, otherwise it may cause valve damage. Warning: For butt-welded ball valves, please do not install them when the valve is closed. If the valve must remain closed, apply grease to the exposed ball surface to protect it from damage by flying welding slag.
6. During preheating, welding, and thermal stress relief, the temperature at any point on the valve body 75 mm away from the weld seam must not exceed 200 ℃. Please use a thermometer to check the temperature.
7. During valve installation, the cleanliness of the valve body cavity should be ensured to prevent debris from entering the cavity;
8. After installation welding of the welding end valve, visual inspection or non-destructive testing should be carried out to confirm that there are no cracks, weld beads, undercuts, and other harmful defects, and non-destructive testing of the weld seam should be carried out as required:
9. For valves with actuators, the electrical, pneumatic, and hydraulic pipelines should be connected according to the wiring diagram or piping diagram in the manual, and the correctness of the circuit should be confirmed before turning on; the open and closed positions of the valve have been adjusted at the factory and do not need to be readjusted.
10. The actuator of the underground pipeline valve cannot be immersed in water or mud to prevent damage to the actuator;
Note: If the valve is inevitably immersed in water or mud for a long time, please inform the manufacturer in advance so that the manufacturer can take corresponding measures in advance.
11. When installing large-diameter welded ball valves, the weight of the valve cannot be entirely applied to the pipeline, and fixed piers or supports should be set up for support.
12. Valves with external insulation requirements should have protective layers constructed before the medium is introduced. Set up fixed piers or brackets for support.
12. Valves with external insulation requirements should have protective layers constructed before the medium is introduced.
Design Parameters
Design and Manufacturing: GB/T12237、GB/T37827、GB/T12224、ASME B16.34
Inspection and Testing: GB/T13927、JB/T9092、I5O 5208
Fire Test: GB/T26479、APl 6FA、API607
Pressure Level: 1.6Mpa~4.0Mpa;
Nominal Diameter Range: DN15~1400mm;
Applicable Media: Water, gas, oil, etc;
Applicable Temperature: -29℃~200℃.
Main Component Material Details
| Part Name | Standard Material | Stainless Steel Material | Forging Material |
| Valve Body | 20# | 304 | A105 |
| Valve Cover | 20# | 304 | A105 |
| Ball | 304 | F304 | F304 |
| Valve seat | A105+ENP | 304 | A105+ENP |
| Valve seat seal ring | RPTFE | RPTFE | RPTFE |
| Stem | 20CR13 | 304SS | 20CR13 |
| Packing gland | 20# | 304 | A105 |
| Spring | INCONEL X-750 | INCONELX-750 | INCONEL X-750 |
| Pivot | 20CR13 | 304SS | 20CR13 |
| Upper and lower diameter | 20# | 304 | A105 |
| Sliding bearing | 304+MOS2+PTFE | 304+MOS2+PTFE | 304+MOS2+PTFE |
| O-ring | Fluororubber | Fluororubber | Fluororubber |
| Anti-static device | 304SS | 304SS | 304SS |
Troubleshooting
Malfunction | Cause of malfunction | Troubleshooting method |
Operation jam | 1. Drive unit damage 2. Packing gland installed at an angle 3. Valve seat area blockage 4. Stem bending and seizing | 1. Maintain and repair the drive unit 2. Loosen the packing gland screws and reinstall the packing gland 3. Turn the handwheel and switch several times in small increments 4. Rectify or replace the stem (please contact our company) |
Valve seat leakage | 1. Valve not fully closed 2. Incorrect setting of the drive unit limit switch 3. Sealing surface damaged due to abrasion | 1. Operate the valve to the fully closed position 2. Adjust the limit switch of the drive unit appropriately 3. Please contact our company for repair |
Stem leakage | 1. Stem seal damaged 2. Stem damaged | 1. Replace stem packing 2. Repair or replace stem (please contact our company) |
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