Bray Series 31H Lug-Style Resilient-Seated Butterfly Valve

Lug-style resilient-seated butterfly valve for HVAC and industrial pipeline isolation, available with EPDM or BUNA-N seats.

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The Bray Series 31H is a lug-style resilient-seated butterfly valve available in sizes NPS 2 to 20 (DN 50 to 500), compatible with ASME Class 125/150 and EN 1092 PN16 flanges. The valve has a maximum working pressure of 250 psi (17.2 Bar), an operating temperature range of -29°C to 121°C, and bidirectional bubble-tight shutoff. It is suitable for isolation in HVAC water systems, high-pressure industrial pipelines, and utility service lines.

Specifications

Size Range: NPS 2 to 20 / DN 50 to 500
Body Material: Cast iron, ductile iron
Body Type: Lug
Operating Temperature Range: -29°C to 121°C
Maximum Operating Pressure: 250 psi (17.2 Bar)
Sealing Class: Bi-directional bubble-tight shutoff
Seat Material: Bonded EPDM, bonded BUNA-N
Disc Material: Nylon 11-coated ductile iron, nickel aluminum bronze, stainless steel
Stem Material: 416 stainless steel
Coating: Polyester coating
Flange Drilling Standard: ASME B16.1 Class 125, ASME B16.5 Class 150, EN 1092 PN16
Face-to-Face Standard: MSS SP-67, API 609 Category A, EN 558 Series 20
Testing Standard: MSS SP-61, API 598, EN 12266-1, ISO 5208
Certifications: ABS, ATEX, CRN, DNV, NSF 61/372, PED, PE(S)R, SIL, TR CU

Application scenarios

HVAC Water System Isolation

For isolating HVAC piping within the valve's pressure and temperature limits. The 31H series is compatible with ASME Class 125/150 and PN16 flanges, provides bidirectional bubble-tight sealing, and is listed for HVAC applications in the product literature.

High-Pressure Industrial Pipeline Isolation

For isolating industrial pipelines within the maximum allowable operating pressure of 250 psi and the temperature range of -29°C to 121°C. High-pressure service is listed as an application in the product literature, which specifies bidirectional bubble-tight sealing for the valve.

Terminal Service Pipeline Isolation

For isolating pipelines at terminal service locations. The 31H series is a lug-style resilient-seated butterfly valve compatible with ASME Class 125/150 and PN16 flanges, and provides bidirectional bubble-tight sealing; terminal service is listed as an application in the product literature.

Selection points

Bonded EPDM or BUNA-N Seat

The valve is available with bonded EPDM or bonded BUNA-N seat options. Select the seat material according to the process medium and temperature conditions.

Bidirectional Bubble-Tight Shutoff and Secondary Stem Seal

The product provides bidirectional bubble-tight shutoff, with primary and secondary seals between the disc and seat and between the stem and seat to reduce the risk of internal and external leakage.

Multiple Disc Materials and Polyester Coating Configurations

Available disc options include Nylon 11-coated ductile iron, nickel aluminum bronze, or stainless steel. The valve body features a polyester fiber coating, allowing material combinations to be selected according to media conditions.

Lug-Style Body and Multi-Standard Flange Drilling

The product features a lug-style body with flange drilling compliant with ASME B16.1 Class 125, ASME B16.5 Class 150, and EN 1092 PN16 standards.

Installation & maintenance notes

Verify Flange Standard and Disc Clearance

Before installation, verify that the mating flange complies with ASME B16.1 Class 125, ASME B16.5 Class 150, or EN 1092 PN16 standards. Confirm that the flange bore diameter and pipe alignment provide sufficient clearance for disc operation to prevent contact between the disc and adjacent pipe or flanges, which could cause disc or seat damage, improper operation, and sealing failure.

FAQ

What is the operating principle of the Series 31H resilient-seated butterfly valve?

The Series 31H features a one-piece stem connection, with primary and secondary seals between the disc and seat and between the stem and seat. Sealing is achieved through the interference fit between the disc and seat. During opening, the stem drives the disc to open, enabling fluid control.

What key points should be considered when selecting this valve?

Consider the size range (DN/nominal diameter), flange standards and drilling (ASME B16.1/125, 150, EN 1092 PN16), body material, stem material, sealing material, temperature and pressure limits, and applicable testing and certifications to ensure compatibility with the medium and system conditions.

How does the Series 31H demonstrate durability in harsh environments?

It combines a corrosion-resistant polyester-coated body, a 416 stainless steel stem, a dual-seal design, and a Nylon 11-coated disc with a cast iron or ductile iron body to provide good corrosion resistance and long-term sealing performance.

How can the sealing performance and leakage class of this valve be determined?

The valve incorporates primary and secondary seals. Its design provides containment of pipeline media and achieves bi-directional bubble-tight shutoff in accordance with relevant industry testing standards. The specific leakage class should be confirmed based on the actual model and operating conditions.

What installation parameters require attention to ensure performance?

Ensure that the valve bore matches the flange holes (ASME/EN standards), that the medium temperature and pressure ranges are correctly defined, and that the appropriate seat material (EPDM/BUNA-N) is selected. Do not exceed the specified temperature and pressure limits, and ensure the flange connection is properly tightened to achieve effective sealing.

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