ZBXY/ZBBPXYL Series Loose Knot Type Flanged Pressure Relief Valve
Loose Knot Type Flanged Pressure Relief Valve for liquid, vapor and steam relief service requiring compact design, high sealing performance and high back-pressure suitability. Key selection data include Threaded and flanged sizes per catalog standard parameter table, NPT, Class 150, Class 300 and Class 600 inlet connection options by model code, Confirm by seal material, body material and service, materials, connection standard and set pressure.
Final set pressure, certified relieving capacity, material code and connection standard must be confirmed on the approved datasheet before purchase.
- Size range: Threaded and flanged sizes per catalog standard parameter table
- Pressure rating: NPT, Class 150, Class 300 and Class 600 inlet connection options by model code
- Temperature: Confirm by seal material, body material and service
- Connection: Male NPT, female NPT, Class 150/300/600 flanged inlet options
- Media: Gas, vapor, liquid, steam and high-back-pressure applications
- Drawings, test records and material documents confirmed for the ordered configuration.
Technical Specifications and Selection Data
Product Model
ZBXY/ZBBPXYL Series
Size Range
Threaded and flanged sizes per catalog standard parameter table
Pressure Rating
NPT, Class 150, Class 300 and Class 600 inlet connection options by model code
Temperature Range
Confirm by seal material, body material and service
Applicable Media
Gas, vapor, liquid, steam and high-back-pressure applications
Connection Type
Male NPT, female NPT, Class 150/300/600 flanged inlet options
Standards and Compliance
ISO 4126-1, API RP 520, API Std 526, API Std 527, ASME Boiler and Pressure Vessel Code Section VIII Division 1, and ASME B16.5 flange references where applicable.
Engineering Insight: Model Logic and Application Boundary
Model code: ZBXY = gas/vapor valve; ZBBPXYL = liquid valve; inlet connection code M/F/01/03/06 identifies NPT or flange class; material code C/S/SM/SL identifies body material.
Typical application: liquid, vapor and steam relief service requiring compact design, high sealing performance and high back-pressure suitability
Capacity review: Balanced piston design compensates for back-pressure changes. Final capacity is selected by gas, vapor, liquid or steam service and set pressure.
This product family should not be selected from model code, nominal size or pressure class alone. Confirm the relieving scenario, required capacity, set pressure, operating margin, temperature, back pressure and actual connection standard.
Dimensions and Selection Guide
Critical dimensions are configuration-specific. Use the verified specification fields below for preliminary review and request the controlled GA drawing for final piping or fabrication approval.
RFQ checklist
RFQ checklist: model or valve type, DN/NPS, PN/Class, set pressure, relieving medium, operating temperature, body and trim material, inlet/outlet connection standard, cap/lever/pilot options, quantity, drawing, certificate and inspection requirements.
Failure Analysis, Manufacturing Evidence and Quality Control
Common misapplication risks: incorrect thread or connection standard, insufficient certified relieving capacity, unsuitable body or trim material, operating pressure too close to set pressure, unreviewed back pressure, and installation loads transferred to the valve.
Material review: body materials: WCB, CF8, CF8M or CF3M body material codes; full 316 stainless, Monel, Hastelloy and NACE-compliant options are available. Trim and internals: Stainless steel internal parts for corrosion resistance; optional 316, Monel, Hastelloy and NACE materials. Spring and stem: Alloy steel or stainless steel spring according to temperature range and material code.
Testing and inspection: Set pressure tolerance within +/-3 percent, overpressure and blowdown per ASME/API service, API 527 seat tightness, shell/seat test, material review and dimensional inspection according to the confirmed order.
Source and scope: product data is based on Zobai Safety Valve Product Catalog.pdf, catalog page 097-102. Project compliance remains subject to the approved datasheet, drawing, calculation and controlled certificates for the ordered configuration.
Review material traceability, type-test scope and project certificate requirements.
Related Products
FAQ
Safety Valve FAQs
What models are covered by this ZBXY/ZBBPXYL Series Loose Knot Type Flanged Pressure Relief Valve page?
ZBXY/ZBBPXYL Series
What size, pressure and temperature data should be confirmed?
Size: Threaded and flanged sizes per catalog standard parameter table. Pressure: NPT, Class 150, Class 300 and Class 600 inlet connection options by model code. Temperature: Confirm by seal material, body material and service. Confirm the exact combination for the selected model.
Which media can this product family handle?
Gas, vapor, liquid, steam and high-back-pressure applications. Material and sealing compatibility require review for the actual fluid composition and temperature.
Can the catalog dimension table be used for final fabrication?
Use it for preliminary review only. Confirm critical dimensions, connection details and orientation on the approved order drawing before piping or equipment fabrication.
What should be included in the RFQ?
RFQ checklist: model or valve type, DN/NPS, PN/Class, set pressure, relieving medium, operating temperature, body and trim material, inlet/outlet connection standard, cap/lever/pilot options, quantity, drawing, certificate and inspection requirements.