UN Series Union Bonnet Needle Valves
Union bonnet needle valves are a type of valve that is used to control the flow of liquids and gases. They are typically used in applications where precise control is required, such as in instrumentation and process control systems.
Union bonnet needle valves are characterized by their union bonnet construction. This means that the bonnet, or body, of the valve is connected to the stem by a union joint. This allows the bonnet to be removed without having to disconnect the piping from the valve. This makes it easy to inspect and maintain the valve without disrupting the flow of fluid.
Needle valves are also characterized by their fine needle-like stem. This stem allows for very precise control of the flow of fluid. Needle valves are typically used to regulate the flow of small amounts of fluid, but they can also be used to control the flow of larger amounts of fluid by using multiple valves in series.
Union bonnet needle valves are available in a variety of materials and sizes to meet the needs of a wide range of applications. Some of the most common materials used for union bonnet needle valves include stainless steel, brass, and bronze. Union bonnet needle valves are also available in a variety of end connections, such as pipe threads, flanges, and compression fittings.


| Item | Component | Valve Body Material | |||||||||||||||||||||||||||||||||||||||||
| 316 SS | Alloy 400 | Titanium | Alloy C-276 | ||||||||||||||||||||||||||||||||||||||||
| 1 | Handle | Anodized aluminum or stainless steel or black knob | |||||||||||||||||||||||||||||||||||||||||
| 2 | Set Screw | Stainless steel | |||||||||||||||||||||||||||||||||||||||||
| 3 | Upper Stem | 316 SS/A276 | |||||||||||||||||||||||||||||||||||||||||
| 4 | Packing Bolt | 321 SS/A276 | |||||||||||||||||||||||||||||||||||||||||
| 5 | Lock Nut | 316 SS/A276 | |||||||||||||||||||||||||||||||||||||||||
| 6 | Panel Nut | 316 SS/B783 | |||||||||||||||||||||||||||||||||||||||||
| 7 | Gland | 316 SS/A276 | Alloy R-405/B164 | Titanium Gr 4/B348 | Alloy C-276/B574 | ||||||||||||||||||||||||||||||||||||||
| 8 | Packing | PTFE or PEEK or graphite | |||||||||||||||||||||||||||||||||||||||||
| 9 | Bonnet | 316 SS/A479 | Alloy R-405/B164 | Titanium Gr 4/B348 | Alloy C-276/B574 | ||||||||||||||||||||||||||||||||||||||
| 10 | UInion Nut | 316 SS/A276 | |||||||||||||||||||||||||||||||||||||||||
| 11a11b | Lower Stem | 316 SS/A276 | Alloy R-405/B164 | Titanium Gr 4/B348 | Alloy C-276/B574 | ||||||||||||||||||||||||||||||||||||||
| 12 | Body | 316 SS/A182 | Alloy 400/B164, | Titanium Gr 4/B348 | Alloy C-276/B564 | ||||||||||||||||||||||||||||||||||||||

| Basic Ordering Number | Connection Type and Size | Orifice In.(mm) | Cv | Dimension, in.(mm) | |||||||||
| Inlet | Outlet | L1 | L2 | L3 | L4 | C | D | E | F | H | |||
| -UN-FN2-4 | 1/8 Female NPT | 1/8 Female NPT | 0.16(4.0) | 0.35 | 1.00(25.4) | 1.00(25.4) | 0.89(22.6) | 1.00(25.4) | 0.39(10.0) | 1.77(45.0) | 1.09(27.7) | 0.59(15.0) | 3.04(77.2) |
| -UN-FN4-4 | 1/4 Female NPT | 1/4 Female NPT | 0.16(4.0) | 0.35 | 1.03(26.2) | 1.03(26.2) | 0.89(22.6) | 1.00(25.4) | 0.39(10.0) | 1.77(45.0) | 1.09(27.7) | 0.59(15.0) | 3.04(77.2) |
| -UN-FN6-6 | 3/8 Female NPT | 3/8 Female NPT | 0.25(6.4) | 0.80 | 1.13(28.6) | 1.13(28.6) | 1.00(25.4) | 1.13(28.6) | 0.50(12.7) | 2.50(63.5) | 1.34(34.0) | 0.78(19.8) | 3.70(94.0) |
| -UN-FN8-10 | 1/2 Female NPT | 1/2 Female NPT | 0.39(10.0) | 1.80 | 1.56(39.6) | 1.56(39.6) | 1.31(33.3) | 1.56(39.6) | 0.78(19.8) | 3.50(88.9) | 1.91(48.5) | 1.03(26.2) | 4.85(123) |
| -UN-FN12-10 | 3/4 Female NPT | 3/4 Female NPT | 0.39(10.0) | 1.80 | 1.63(41.3) | 1.63(41.3) | - | - | 0.78(19.8) | 3.50(88.9) | 1.91(48.5) | 1.03(26.2) | 4.85(123) |
| -UN-FN16-10 | 1 Female NPT | 1 Female NPT | 0.39(10.0) | 1.80 | 1.81(46.0) | 1.81(46.0) | - | - | 1.00(25.4) | 3.50(88.9) | 2.13(54.0) | 1.03(26.2) | 5.10(129) |
| -UN-MN2-4 | 1/8 Male NPT | 1/8 Male NPT | 0.16(4.0) | 0.35 | 1.00(25.4) | 1.00(25.4) | 0.89(22.6) | 1.00(25.4) | 0.39(10.0) | 1.77(45.0) | 1.09(27.7) | 0.59(15.0) | 3.04(77.2) |
| -UN-MN4-4 | 1/4 Male NPT | 1/4 Male NPT | 0.16(4.0) | 0.35 | 1.03(26.2) | 1.03(26.2) | 0.89(22.6) | 1.00(25.4) | 0.39(10.0) | 1.77(45.0) | 1.09(27.7) | 0.59(15.0) | 3.04(77.2) |
| -UN-MN6-6 | 3/8 Male NPT | 3/8 Male NPT | 0.25(6.4) | 0.80 | 1.13(28.6) | 1.13(28.6) | 1.00(25.4) | 1.13(28.6) | 0.50(12.7) | 2.50(63.5) | 1.34(34.0) | 0.78(19.8) | 3.70(94.0) |
| -UN-MN8-10 | 1/2 Male NPT | 1/2 Male NPT | 0.39(10.0) | 1.80 | 1.56(39.6) | 1.56(39.6) | 1.31(33.3) | 1.56(39.6) | 0.78(19.8) | 3.50(88.9) | 1.91(48.5) | 1.03(26.2) | 4.85(123) |
| -UN-MN12-10 | 3/4 Male NPT | 3/4 Male NPT | 0.39(10.0) | 1.80 | 1.63(41.3) | 1.63(41.3) | - | - | 0.78(19.8) | 3.50(88.9) | 1.91(48.5) | 1.03(26.2) | 4.85(123) |
| -UN-MN16-10 | 1 Male NPT | 1 Male NPT | 0.39(10.0) | 1.80 | 1.81(46.0) | 1.81(46.0) | |||||||
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