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The A42H full-opening American Standard safety valve is a full-opening spring safety valve designed and manufactured in strict accordance with American standards (such as ASME Section I/VIII, API 526). The "H" in its name represents that the sealing surface is made of alloy steel. When the system experiences overpressure, the valve disc quickly opens fully to achieve high-flow discharge, and automatically closes after the pressure is restored. It fully meets the American Standard's specifications in terms of structure, dimensions, performance testing (such as pressure regulation and displacement certification), and materials, making it an ideal choice for export equipment or American Standard projects where there are mandatory compliance requirements for safety valves. It is mainly used in boilers, pressure vessels, petrochemical plants, liquefied natural gas (LNG) equipment, offshore platforms, and complete sets of equipment exported, designed or built according to American standards, as a mandatory overpressure protection device that meets regulatory requirements.

A42H Full-Lift American Standard Safety Valve Product Diagram
Features:
1. Designed, manufactured, tested, and inspected in accordance with American standards. Strictly complies with ASME, API, and other standards. The pressure-temperature ratings, structural lengths, flange dimensions, etc. fully meet American standards, ensuring international universality and compliance.
2. The sealing surface between the alloy steel hard seal ("H" type) valve disc and valve seat is made of alloy steel (such as 13Cr, 410SS) through build-up welding or integral machining, featuring high hardness, wear resistance, high temperature resistance, and reliable sealing.
3. The fully-open type large-displacement relief valve adopts a fully-open structure, featuring a large discharge area and strong relief capacity (displacement). Its displacement is usually certified by authoritative institutions (such as NB), making it suitable for steam and gas systems that require rapid and large-scale pressure relief.
4. The spring structure is stable and reliable. The spring design meets American standard requirements, with stable performance, ensuring accurate set pressure, small opening and closing pressure difference, and good repeatability. The adjustment mechanism facilitates precise pressure setting on site.
5. The standard American standard flange connection for inlet and outlet adopts RF or RTJ flanges in accordance with the ASME B16.5 standard, with standard connection dimensions, allowing for seamless docking with American standard piping systems.

A42H Full-Lift American Standard Safety Valve Structural Diagram
Part Name Material
| NO. | 零件名称Name of part | A42Y-C/KA42Y-C Materials | A42Y-P/KA42Y-P Materials | A42Y-R Materials | DA42Y-P Materia |
| 1 | 阀 座 Nozzle | 2Cr13/1Cr18Ni9Ti | ZG1Cr18Ni9Ti | ZG1Cr18Ni12Mo2Ti | ZG1Cr18N |
| 2 | 阀 体 Body | WCB | ZG1Cr18Ni9Ti | ZG1Cr18Ni12Mo2Ti | LCB/ZG1C |
| 3 | 调 节 圈 Adjusting ring | 2Cr13 /1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti | 1Cr18Ni9T |
| 4 | Disc holder | 2Cr13 /1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti | 1Cr18Ni9T |
| 5 | 阀 瓣 Disc | 2Cr13 /1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti | 1Cr18Ni9T |
| 6 | 导 向 套 Guide sleeve | 2Cr13 /1Cr18Ni9Ti | 1Cr18Ni9Ti | 1Cr18Ni12Mo2Ti | 1Cr18Ni9T |
| 7 | 阀 盖 Bonnet | ZG230-450 | ZG230-450 | ZG230-450 | ZG1Cr18N |
| 8 | 弹 簧 Spring | 50CrVA | 50CrVA Coated Teflon | 50CrVA Coated Teflon | 50CrVA |
| 9 | 阀 杆 Stem | 2Cr13 | 1Cr18Ni9Ti/1Cr18Ni12Mo2Ti | 1Cr18Ni9Ti/1Cr18Ni12Mo2Ti | 1Cr18Ni9T |
| 10 | Adjusting bolt | 45 | 2Cr13 | 2Cr13 | 2Cr13 |
| 11 | Cap | ZG200-400 | ZG200-400 | ZG200-400 | ZG230-45i |
Performance Specifications Table
| 型号 model | 铸钢型 Cast steel type |
| 口径范围 Caliper range | DN20-DN400 |
| 适用温度 application temperature | ≤300℃ |
| 适用介质 application media | 空气、石油气、液体 Air, petroleum gas, liquid |

A42H Full-Lift American Standard Safety Valve Outline Drawing
Dimension Chart
| 公称通径 DN(mm) | do | DN' | L | L1 | ≈H |
| 20 | 15 | 25 | 100 | 85 | 291 |
| 25 | 16 | 32 | 110 | 95 | 291 |
| 32 | 20 | 40 | 115 | 100 | 293 |
| 40 | 25 | 50 | 120 | 110 | 302 |
| 50 | 32 | 65 | 135 | 120 | 323 |
| 65 | 40 | 80 | 160 | 135 | 394 |
| 80 | 50 | 100 | 170 | 135 | 410 |
| 100 | 65 | 125 | 195 | 175 | 545 |
| 100 | 65 | 150 | 176 | 185 | 581 |
| 125 | 80 | 150 | 210 | 190 | 578 |
| 150 | 100 | 175 | 255 | 230 | 601 |
| 150 | 100 | 200 | 250 | 210 | 619 |
| 200 | 125 | 250 | 300 | 260 | 734 |
| 250 | 150 | 300 | 350 | 320 | 885 |
| 300 | 220 | 400 | 380 | 350 | 1243 |
| 350 | 250 | 500 | 500 | 450 | 1340 |
| 400 | 280 | 500 | 500 | 450 | 1340 |

Model:
A27H-16C/A27H-25C/A27H-40C/A27H-64C/A27H-16P/A27H-25P/A27H-40P/A27H-64P/A27H-16T/A27H-25T/A27H-40T/A27H-64TSpecification:
DN15-DN80Pressure:
16PN-64PNMaterial:
cast steel, stainless steel, copper
Model:
AHN42FSpecification:
DN10~DN600Pressure:
PN1.6~PN32Material:
stainless steel WCB, ZG1Cr18Ni9Ti, CF8M
Model:
A37H-10C/A37H-16C/A37H-25C/A37H-40C/A37H-64C/A37H-100C/A37H-10C/A37H-16P/A37H-25P/A37H-40P/A37H-64P/A37H-100P/A37H-10C/A37H-16R/A37H-25R/A37H-40R/A37H-64R/A37H-100RSpecification:
DN15-DN80Pressure:
10PN-100PNMaterial:
cast steel, stainless steel, bi-directional stainless steel