Pressure Seal Y-Pattern Globe Valve

A pressure seal Y-pattern globe valve is a 45 degree globe valve whose seat and stem are inclined to the pipe axis, closed by a bonnet that line pressure seals against itself. Built to API 623:2021 with a bonnet joint to MSS SP-144-2020, it covers NPS 2 to 24 in Class 600 to 2500 - the range where a straight-pattern body's pressure drop stops being an accounting detail and becomes pump head paid every hour.

Design Standard

Design Features

1. Segmental thrust ring absorbs the outward thrust along the stem generated by the internal pressure.
2. Thrust rings to prevent deformation of the gaskets.
3. Stainless steel intemals to ensure soundness and corrosion-resistance in the vital body sealing zone for carbon and alloy steel valves.
4. Soft steel gasket seal to provide large contact area for a perfect sealing.
5. Anti-blowout with collar design.
6. Compared with the gate valve, globe valve has a simple structure and easy for maintenance.
7. Short stroke, and short time for opening and shutoff.
8. Sealing surface is not easily worn and abraded during opening and shutoff, with good sealing performance and long service life.
9. Y-pattern design reduces the resistance of the flow.
10. Disc fully guided reduces the impact of medium onto both disc and stem,with excellent sealing performance.
11. Seat ring is overlay welded with Stellite 6 or equivalent.
12. By-pass and drain valve are available when required

Pressure Seal Y-Pattern Globe Valve drawing

Material of Construction

Dimension & Weight

Gear Operation

Class 600

Class 900

Class 1500

Class 2500

Valve Factory

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FAQ

What is the difference between a Y-pattern and a T-pattern globe valve?

A T-pattern body turns the flow through two right angles, with the stem perpendicular to the pipe axis. A Y-pattern body inclines the seat and stem about 45 degrees, so the same flow turns through two shallow bends instead. The trim is the same; the hydraulics and the body length are not. Crane TP-410 puts a straight-pattern globe at L/D 340 and a Y-pattern globe at L/D 55 at full open, so the Y body is a hydraulic decision inside the globe valve family rather than a different valve type.

Does a pressure seal Y-pattern globe valve have a standard face-to-face dimension?

Only at Class 150. ASME B16.10-2022 paragraph 1.5.2 covers Y-pattern globe and Y-pattern swing check valves in Class 150 alone, in Table 1.3-1, and no Y-pattern column exists for Class 300, 600, 900, 1500 or 2500. Since MSS SP-144 begins at Class 600, every pressure seal Y-pattern globe valve is dimensioned to the maker's drawing. Ask for a certified general arrangement drawing and check it against the spool before the valve is built.

What does NPS 6 x 4 x 6 mean on a pressure seal valve?

It is the size designation for a reduced port pressure seal valve: end size, port size, end size. ASME B16.10-2022 paragraph 2.1.3(b) sets the convention and adds the rule that matters: such a valve takes the face-to-face dimension of its port size, not of its end size. An NPS 6 x 4 x 6 valve is therefore as long as an NPS 4 valve. A supplier who dimensions by end size will deliver a valve that does not fit the gap it was measured for.

Is a pressure seal Y-pattern globe valve an API 600 valve?

No. API 600 is titled Steel Gate Valves - Flanged and Butt-welding Ends, Bolted Bonnets, and it covers gate valves only. The globe valve standard is API 623, whose second edition of 2021 is the current one. For two decades globe valve data sheets quoted API 600 wall thicknesses because no other document offered a wall table, which is the practice API 623 was written to correct.

Which standard governs: API 623, MSS SP-144 or BS 1873?

API 623:2021 for the valve and MSS SP-144-2020 for the bonnet joint. API 623 covers steel globe valves from NPS 2 to 24 in Class 150 to 2500, and its 2021 scope lists Y-pattern among the body types and pressure seal bonnet among the features covered. MSS SP-144 runs from NPS 2 to 50 and Class 600 to 4500 and adds the construction rules for the joint itself. BS 1873 is withdrawn and replaced by EN 13709, which stops at Class 600, so it cannot govern a valve in the classes where a pressure seal bonnet is used.

How much pressure drop does the Y body actually save?

At full open, Crane TP-410 gives L/D 55 for a Y-pattern globe against 340 for a straight-pattern body. Because the resistance coefficient is L/D multiplied by the friction factor, the Y body loses about 16 percent of what the straight body loses at the same friction factor, and at equal port size and equal pressure drop it passes about 2.5 times the flow. Two limits apply: those are full-open values, and once the disc is throttled well off its seat the trim governs and the body pattern matters much less.

What size and class range can you supply?

NPS 2 to 24 in Class 600, 900, 1500 and 2500, which is the overlap between API 623 and MSS SP-144-2020. MSS SP-144 itself covers NPS 2 to 50 and Class 600 to 4500, but above NPS 24 and above Class 2500 there is no globe valve parent standard, so those sizes are quoted against a drawing instead. Class 150 and Class 300 are not offered with a pressure seal bonnet, because the pressure is too low to energise the gasket and MSS SP-144 does not cover them.

Which body material for 540 °C main steam?

A217 WC6 or A217 WC9 with CoCr-A hardfacing on seat and disc. A216 WCB stops at 425 °C and belongs on feedwater, drains and blowdown rather than on the main steam line. Above about 600 °C the choice moves to A217 C12A. At 540 °C the bonnet bolting is often the limiting item: A193 B7 is limited to 538 °C, so the joint needs A193 B16 with A194 grade 4 or 7 nuts.

Why is the high-pressure seat test the one that matters here?

Because API 598 puts globe valves and parallel slide gate valves in one column, and in that column the high-pressure closure test is required from Class 900 upward while the low-pressure air test becomes optional. A purchase order that says only API 598 therefore buys the high-pressure test by default, and buys the air test only if it is named. For gear operated and power operated globe valves the test pressure is 110 percent of the design differential used to size the operator, not 1.1 times the cold rating.

Can a Class 2500 valve carry an API 624 certificate?

No. API 624 excludes valves above Class 1500 or larger than NPS 24, so at Class 2500 the type test cannot exist and no report can be issued against it. API 623 still asks for the design to be qualified to API 624, but the two documents do not meet at the top of the range. At Class 2500 ask for an API 622 qualified packing set and an ISO 15848-1 type test instead.

Is the pressure seal gasket reusable, and can the seat be repaired in line?

The gasket is single use: it is pressed into a plastic set between the body taper and the bonnet and cannot re-seat once disturbed. The seat cannot be reached without taking the bonnet off, so a seat repair is a workshop job rather than a line job. Keep one gasket per valve in stores, matched to that valve's drawing or serial number rather than to its size and class alone.

Will it replace a straight-pattern globe valve in the same spool?

Not without measuring. At Class 150 the standard dimensions diverge: Table 1.3-1 gives NPS 6 a Y-globe length of 368 mm against 406 mm in the straight globe column, so the Y body is 38 mm shorter in the same line. Above Class 150 the Y-globe length is not standardised at all and two suppliers can differ by more than the flange tolerance. Assume a spool piece or a pipe modification until the drawing proves otherwise.

What is the minimum order, lead time and documentation?

One piece is accepted, so a single valve can be bought for a maintenance job or for evaluation before a larger order. Common sizes in A216 WCB and A217 WC6 ship in about 7 days from stock; made-to-order valves in WC9, C12A or non-standard end connections run about 20 to 25 days plus transit from Tianjin. Documentation is EN 10204 3.1 as standard and 3.2 when independent witnessing is required, with the API 598 test report, positive material identification on alloy and stainless bodies, and marking to MSS SP-25.