When a butterfly valve on a mud system or a water line has to be replaced, the part number on its tag is often all there is to go on. DEMCO numbers are more useful than most because the number is the specification: size, body, stem, disc and seat are all encoded, and reading them avoids ordering a lug valve for a wafer slot or a Buna-N seat for a hot line.
/01The base number: series and size.
| Size | NE-C | NE-I | NE-D |
|---|---|---|---|
| 2" | 19 | 28 | 81 |
| 2-1/2" | 20 | 29 | — |
| 3" | 21 | 30 | — |
| 4"Highlighted | 22 | 31 | 83 |
| 5" | 23 | 32 | 84 |
| 6" | 24 | 33 | 85 |
| 8" | 25 | 34 | — |
| 10" | 26 | 35 | — |
| 12" | 27 | 36 | — |
The bases in this table are the 200 psi shut-off valves, numbered J0221xx. Bases beginning J0222 cover the other shut-off ratings — 285 psi high-pressure, 50 psi low-torque and throttling — so J022230, for example, is a 6" valve at 285 psi. A J prefix and the leading zeros are part of the Cameron numbering and carry no size information.
/02The suffix, character by character.
| Position | Meaning | Codes |
|---|---|---|
| 1Highlighted | Body style | 1 wafer; 5 lug |
| 2 | Body material | 1 ductile iron; 2 cast (grey) iron; 4 carbon steel |
| 3 | Stem | 1 416 stainless; 2 316 stainless |
| 4 | Disc | 2 316 stainless; 3 Monel; 4 aluminium bronze; 5 nickel-plated ductile iron; 6 PVF-coated ductile iron |
| 5–6 | Seat | 31 Buna-N; 34 Viton; 35 EPDM; 36 natural rubber |
| 7 | Operator | Not decoded — confirm the handle or gear separately |
/03Two worked examples.
J022122-1215311: base 22 is a 4" NE-C; suffix 1 wafer, 2 cast iron body, 1 416 stem, 5 nickel-plated ductile iron disc, 31 Buna-N seat, then the operator code. It is one of the part numbers on our 4" NE-C wafer listing. J022122-5122351: the same 4" NE-C, but 5 lug, 1 ductile iron body, 2 316 stem, 2 316 disc and 35 EPDM seat — on our 4" NE-C lug listing. Changing one digit changed the body style, body, stem, disc and seat.
/04Wafer or lug, and the two pressure ratings.
A wafer valve is clamped between two flanges by bolts that pass around it, so it cannot hold pressure with the downstream pipe removed. A lug valve has tapped lugs that bolt to each flange separately, and our lug listings are marked as capable of end-of-line service. Two pressures appear on every listing: the body rating, ASME Class 150 at 285 psi non-shock, and the drop-tight shut-off rating, 200 psi bi-directional on the standard valves. The valves are also rated for vacuum to 29.9 in Hg. Our NF-C valves, 14" to 36", shut off at 150 psi standard.
/05Choosing seat and disc.
The seat sets the temperature window: on our listings Buna-N is 0 °F to 180 °F (−18 °C to 82 °C), EPDM 20 °F to 275 °F (−7 °C to 135 °C) and Viton 20 °F to 300 °F (−7 °C to 149 °C). Buna-N suits oil, water and drilling mud at ambient temperature; EPDM hot water and steam-cleaned lines but not oil; Viton hot oils and chemicals. The disc meets the flow: nickel-plated ductile iron for general duty, aluminium bronze and Monel for seawater, 316 stainless for corrosive and food service. Sanitary NE-I and Teflon-lined NEI-T valves are listed for FDA service.
Frequently asked questions
- What size is a DEMCO J022125 valve?
- An 8" NE-C — base digits 25 on the NE-C series. The suffix then gives the body style and materials.
- What does seat code 34 mean?
- Viton (FKM). The other seat codes are 31 Buna-N, 35 EPDM and 36 natural rubber.
- Can a wafer butterfly valve be used at the end of a line?
- No. A wafer valve needs flanges on both sides to hold it. Use a lug valve, which our listings mark as end-of-line capable.
- What pressure does a DEMCO NE-C valve shut off?
- 200 psi drop-tight, bi-directional, in an ASME Class 150 body rated 285 psi. Other bases are available for 285 psi, 50 psi low-torque and throttling.
DEMCO butterfly valves
IH-VAL-BFLY-NEC-W-4DEMCO Series NE-C Wafer Butterfly Valve, 4″, 200 psiDEMCO
IH-VAL-BFLY-NEC-L-4DEMCO Series NE-C Lug Butterfly Valve, 4″, 200 psiDEMCO
IH-VAL-BFLY-NEC-L-6DEMCO Series NE-C Lug Butterfly Valve, 6″, 200 psiDEMCO
IH-VAL-BFLY-NEI-W-6DEMCO Series NE-I Wafer Butterfly Valve, 6″, 200 psiDEMCO
IH-VAL-BFLY-NED-W-4DEMCO Series NE-D Wafer Butterfly Valve, 4″, 200 psiDEMCO- IH-VAL-BFLY-NFCDEMCO Series NF-C Large-Bore Butterfly Valve, 14″–36″DEMCO
- IH-VAL-BFLY-NEITDEMCO Series NEI-T Teflon-Lined Sanitary Butterfly Valve, 2″–10″DEMCO
- IH-VAL-BFLY-WGODEMCO Worm-Gear Operator for Butterfly Valves, 2″–36″DEMCO
