HHSV Safety Relief Valve Range
Choose the protection function first. Then choose the valve architecture.
HHSV manufactures safety and pressure-relief products for industrial pressure protection. The range is organized by operating principle, special pressure-control function and system role – not by mixing lift, temperature, bellows and application labels into one level.
Product Architecture
Relief valves · special functions · protection systems
How the Range Is Structured
Three different classification layers - kept visibly separate.
A configuration such as Full Lift or Balanced Bellows can exist inside an operating family. A function such as Back-Flow answers a different system requirement. Accessories and combinations sit at the protection-system layer.
01 · Relief-Valve Operating Families
Spring-Loaded · Pilot-Operated · Impulse & Main systems. These change how pressure is sensed and how the relieving element is actuated.
02 · Special Pressure-Control Functions
Back-Flow · Vacuum / Breather. These are separated because the protected pressure direction or system function is different.
03 · Protection-System Layer
Quick crossover devices and bursting-disc + safety-valve combinations support the pressure-protection system; they are not another valve operating principle.
Product Family Explorer
Six buyer-facing entry points, but not six identical taxonomy concepts.
Each page has its own sizing or system-selection logic. Product features such as Full Lift, Low Lift, Duplex Spring, High Temperature, High Pressure, Radiator, Welded, Jacketed and Clean Service remain inside the appropriate family page.
Operating family
Spring-Loaded Safety Relief Valves
Direct spring force closes the disc. Includes conventional, balanced-bellows and multiple lift/service configurations.
Leaflet product coverage
HFA38 · HFA48SB · HFA44 · HFA42 · HFA41 · HFA40 · HFO/HFB · HFGS · HFA900 · HFA28 · HFA22 · HFXY/HFBPXYL · HFNJ · HFA21 and other leaflet spring-loaded/special-service records
Operating family
Pilot-Operated Safety Relief Valves
A pilot controls the main valve. Selection depends on relieving case, pressure behavior, backpressure and project/code requirements.
Leaflet product coverage
HFXD Series Pilot-Operated Safety Relief Valve
Special function
Back-Flow Safety Valves
A dedicated return/back-flow protection function. Do not confuse it with a balanced-bellows valve used to compensate backpressure.
Leaflet product coverage
HFAHN42F Series parallel/bellows safety back-flow valve
Operating system
Impulse & Main Safety Valve Systems
Impulse device and main safety valve work as a coordinated protection system for high-capacity steam/pressure service.
Leaflet product coverage
HFA49 Main Safety Valve · HFGA49 Impulse Safety Device
Special function
Vacuum & Breather Valves
Protect equipment against negative pressure or manage equipment/tank breathing rather than ordinary positive-pressure relief alone.
Leaflet product coverage
HFA72W Vacuum Negative Pressure Safety Valve · HFHX Breather Valve
System layer
Safety Relief System Accessories & Combinations
Changeover and combined protection devices used around the safety valve, not a separate pressure-relief actuation principle.
Leaflet product coverage
HFKH Quick Crossover Device · Bursting Disc + Safety Valve Combination
Critical Classification Distinction
Balanced Bellows is about backpressure. Back-Flow is about reverse/return flow.
The two terms can look similar in translated product literature, but they answer different engineering questions and must not be merged into one first-level family.
Balanced-Bellows Spring-Loaded Valve
A spring-loaded construction using bellows to reduce the influence of backpressure on set behavior and, where applicable, isolate bonnet internals. It belongs inside the Spring-Loaded Tank Page.
Back-Flow Safety Valve
A separate functional product for return/reverse-flow protection. The Leaflet identifies HFAHN42F as the dedicated back-flow series; bellows construction does not turn every balanced-bellows relief valve into a back-flow valve.
Leaflet Product Routing Matrix
Every product record should have one primary Tank Page route.
The table keeps the browsing structure stable while allowing configuration, application and standards taxonomies to cut across the product families.
| Tank-page route | Leaflet-listed series / products | Keep inside the page as configuration or service attributes |
|---|---|---|
| Spring-Loaded | HFA38; HFA48SB; HFA44; HFA42; HFA41; HFA40; HFO; HFB; HFGS high-temperature; HFA900; HFA28; HFA22; HFXY/HFBPXYL; HFNJ; HFA21; HFGS welded-type; other spring-labeled special-service records | Conventional / balanced bellows · full/low lift · duplex spring · high temperature / pressure · radiator · welded · threaded · jacketed · clean service |
| Pilot-Operated | HFXD Series Pilot-Operated Safety Relief Valve | Pilot/main-valve arrangement · pressure class · backpressure behavior · materials · connection |
| Back-Flow | HFAHN42F Series parallel/bellows safety back-flow valve | Back-flow function · bellows construction · service media · direction / installation requirements |
| Impulse & Main | HFA49 Main Safety Valve + HFGA49 Impulse Safety Device | Main/impulse roles · steam service · system actuation · piping / installation arrangement |
| Vacuum & Breather | HFA72W Vacuum Negative Pressure Safety Valve + HFHX Breather Valve | Vacuum / pressure direction · breathing capacity · set condition · service/application |
| Protection Systems | HFKH Safety Valve Quick Crossover Device + Bursting Disc and Safety Valve Combination | Changeover logic · isolation · rupture-disc interaction · maintenance / inspection strategy |
Leaflet records such as HFYA800 high-pressure relief valve and HFSVL488 clean-service stainless-steel safety valve should be assigned to a Tank Page only after the product record confirms the actual operating mechanism; service name alone is not a mechanism.
HHSV Published Overall Envelope
Company capability is not a universal model rating.
The Leaflet states the overall manufacturing envelope below. Each product series occupies only a subset. Contract selection must use the exact model datasheet, calculation, pressure-temperature rating and certificate scope.
Overall size envelope
DN10-600
1/2-24 in
Overall pressure envelope
0.6-42 MPa
Class 150-2500
Overall temperature envelope
-196 to 570 C
Model / material dependent
Media
Steam · Gas · Liquid
Service and model dependent
Materials
Carbon · alloy · stainless
Duplex / special alloys by product
Connections
Flanged · threaded · other
Series / drawing dependent
Sizing & Backpressure
Selection begins with the relieving or protection case - not the product label.
Provide medium/phase, required capacity or protection duty, operating and set pressure, relieving temperature, superimposed/built-up backpressure, connection, material and applicable code. API 520 or ISO 4126 sizing is used where appropriate to the selected product and project.
Backpressure is especially important for conventional versus balanced-bellows spring-loaded products. Reverse/return flow is a different functional requirement and routes to the Back-Flow Tank Page.
Standards, Testing & Certification
Design basis, test basis and certification scope are different claims.
Use the Leaflet standards as routing information, then connect the selected model to the actual project requirement, test record and current certificate/authorization scope.
API 520
Sizing, selection and installation basis where applicable to the product/project.
API 526
Flanged steel pressure-relief dimensions/orifice conventions only for series that use the standard.
API 527
Seat-tightness test basis where specified; it is not a product certification statement.
ISO 4126
Safety-valve design/sizing/testing requirements where applicable to the selected series.
ASME BPVC
Section VIII / applicable authorization must match the supplied model; do not generalize one authorization to the entire range.
GB/T 12241 / 12243
Leaflet-listed Chinese product-standard basis for applicable safety-valve series.
Designed to
The standard is used as the applicable design, sizing or dimensional basis.
Tested in accordance with
The stated test method and acceptance criteria apply to the agreed supplied scope.
Certified to
Use only when legal entity, factory, model/range and marking are inside the actual approval scope.
Testing & Documentation
The selected valve and its evidence should remain connected.
Depending on product and contract scope, HHSV can provide material records, serial-number traceability, pressure/set testing, reseating evidence, API 527 leakage records where applicable, dimensional drawings, datasheets, sizing calculations, inspection documents and final MDR deliverables.
Leaflet Application Coverage
Application identifies the risk context; service data selects the product family and model.
Do not use an industry label as proof that every HHSV safety-valve product is suitable for that service.
Power Generation
Steam, boiler and pressure-system protection with code- and model-specific verification.
General Industrial
OEM, compressor, vessel and packaged-equipment protection across gas/liquid/steam services.
Oil & Gas Production
Pressure-relief products selected from process duty, backpressure, materials and owner requirements.
Refining & Petrochemical
Conventional/balanced/pilot/system solutions routed from service data rather than industry label alone.
Chemical & Process
Material compatibility, leakage, toxic/corrosive service and documentation can control the selection.
Pulp, Paper & Desalination
Application-specific media/material requirements are checked against the actual model and certification scope.
Buyer Path
Move from function to evidence in four steps.
01 · Choose family
Identify overpressure, back-flow, vacuum/breathing or system-protection duty.
02 · Open Tank Page
Compare the relevant HHSV models only within the correct functional/operating family.
03 · Engineering selection
Confirm capacity, pressures, temperature, backpressure, materials, standards and documentation.
04 · Request a Quote
Receive the selected model, sizing basis, deviations, drawings, test/certificate scope and delivery boundary.
Start with the Protection Requirement
Send the RFQ, datasheet, process specification or existing valve nameplate.
HHSV can identify missing service inputs, route the enquiry to the correct family, complete sizing/configuration review and return an approvable technical quotation package.