FLOATING BALL VALVE VS. TRUNNION BALL VALVE DESIGN
FLOATING BALL VALVE VS. TRUNNION BALL VALVE DESIGN
| FLOATING BALL VALVE DESIGN |  |
| TRUNNION BALL VALVE DESIGN |  |
STEM PACKING DESIGNS
| SINGLE PIECE STEM PACKING |  |
| V-RING STEM PACKING |  |
| TRUNNION BALL VALVE DESIGN |  |
BALL SEATS RETAINER
BONOMI’S DOUBLE O-RING STEM DESIGN
- Bonomi's offer has 3 stem seals.
- The first stem seal is a PTFE thrust washer that guarantees the stem sealing, as it is pressed against the valve body. It also avoids the seizing of the stem to happen when the stem gets pushed up by the force of the fluid’s internal pressure. Please duly note that by using full balls there is such thing as a direct contact between the internal pressure of the fluid and the stem. Therefore the stem remains the protected. Such pressure can cause the seizing of the stem and create brass particles that slip between ball and stem seat. Furthermore the open-close system becomes harder to handle and irregular. Therefore the PTFE thrust washer in that position plays a very important role.
- The second stem seal is made by an NBR O-ring, guaranteeing the stem sealing in case the thrust washer lets something go through. It is suitable for contact with drinking water, gas and many other fluids. Moreover, it assures no leakage around the stem at extremely low temperatures.
- The solution we are offering does not have a packing gland because it is not necessary, as specified at point 4.5.1 of MSS-SP-110. Our solution (161N) can guarantee a perfect stem sealing in time under any conditions.
Summarizing, to answer to your comments pertaining to point 3, please note that:
- the valve model we are offering does not have a packing gland
- no packing gland means no stem seat exposed to the environment
- no packing gland means no action by the double-D shape in the handle while rotating.
- the three stem seals we offer in our valve are the perfect match to guarantee the stem sealing
- the double O-ring stem sealing was tested with the following standard: ASME B16.33, CGA 3.16-M88, CGA CR91-002, AGA Requirement N.3-88, ANSI/UL 256, ANSI/UL 842, FM 1140.
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