Body Material & Series
1520B303 Stainless Steel Body Construction (Standard industrial fluid service)
1520C316 Stainless Steel Body Construction (Required for flanged units & NACE MR0175)
Product page
SOR
1520 Top-Mounted Electric Flow Switch
The SOR 1520 Top-Mounted Electric Flow Switch is a compact, robust, vane-actuated flow/no-flow detection instrument engineered for plant process lines and OEM equipment where open or closed dry contacts are required to signal positive fluid movement or flow failure. Operating on a vertical top-mount orientation, flowing media deflects a 316SS vane assembly attached to a pivot arm, moving an internal magnet that magnetically couples through a solid non-magnetic pressure barrier to actuate or deactuate a hermetically sealed reed switch capsule. This magnetic-coupling design completely isolates electrical switching circuits from the process fluid without dynamic mechanical seals or packing glands, eliminating leak paths. Rated for working pressures up to 5,000 psi (345 bar) and process temperatures from -40 °F to 400 °F (-40 °C to 204 °C), the 1520 switch is available in threaded 1-1/2" or 2" NPT(M) and ANSI 150# to 600# flanged process connections in 303SS or 316SS with full NACE MR0175 compliance. Equipped with CSA, ATEX, IECEx, and INMETRO explosion-proof and intrinsically safe approvals, single-seal compliance to ANSI/ISA 12.27.01, SIL 1/SIL 2 functional safety certification, and backed by SOR's 5-year limited manufacturer warranty.
Vertically mounted vane-operated design engineered for direct installation into 1-1/2" through 6" process pipelines
Magnetic coupling actuates hermetically sealed reed switch through solid barrier, eliminating dynamic seals and leak points
Working pressures from full vacuum up to 5,000 psi (345 bar) and process temperatures from -40 °F to 400 °F (-40 °C to 204 °C)
Minimum actuation flow velocity as low as 1 FPS (0.3 m/s) with minimal pressure drop across the pipeline
Ready for quotationShare your range, connection and case requirement.
Talk to ATHPipeline Sizes1-1/2" through 6" (38 mm to 150 mm) line diameters
Maximum Process PressureUp to 5,000 psi (345 bar) [flange rating dependent]
Process Temperature Range-40 °F to 400 °F (-40 °C to 204 °C)
Minimum Actuation Velocity1.0 FPS (0.3 m/s) liquid flow rate
Switching MechanismHermetically sealed reed switch SPST or SPDT (0.9A @ 110 VAC, 3A @ 28 VDC, 20 AWG leads)
Optional Relay ModulesRB (24 VDC) or RC (120 VAC) powered 10A @ 115 VAC DPDT relay in explosion-proof housing
Process Connections1-1/2" & 2" NPT Male threaded, or 2-1/2" to 6" ANSI 150#/300#/600# RF Flanged
Wetted Metallurgy303 Stainless Steel (standard) or 316 Stainless Steel (NACE MR0175 compliant)
Electrical Conduit Entry1/2" NPT Female standard (3/4" NPT Female optional with CR adapter)
Agency ApprovalsCSA Certified (US & Canada), ATEX/IECEx (Ex d / Ex ia), INMETRO, ANSI/ISA 12.27.01 Single Seal
Safety Rating & WarrantyIEC 61508 SIL 1/2 Certified | SOR 5-Year Limited Warranty
Engineering Specifications & Selection Matrix
SOR 1520 Top-Mounted Electric Flow Switch Technical Guide
Configure your SOR 1520 flow switch by selecting body metallurgy, pipe connection style, switch contact mechanism, electrical housing, and agency certifications.
Pipe Sizes1-1/2" to 6" Lines
Max Pressure5,000 psi (345 bar)
Process Temp-40 °F to 400 °F (-40 °C to 204 °C)
Safety / WarrantySIL 1/2 Certified / 5-Year Warranty
Process Connection Size & Type
F5A1-1/2" NPT Male Threaded Process Connection (Up to 5,000 psi / 345 bar)
F2A2" NPT Male Threaded Process Connection (Up to 5,000 psi / 345 bar)
F7C2-1/2" ANSI 150# Raised Face Flange (316SS Body Only)
F7D2-1/2" ANSI 300# Raised Face Flange (316SS Body Only)
F3C3" ANSI 150# Raised Face Flange (316SS Body Only)
F3D3" ANSI 300# Raised Face Flange (316SS Body Only)
F4C4" ANSI 150# Raised Face Flange (316SS Body Only)
F6C6" ANSI 150# Raised Face Flange (316SS Body Only)
Vane Material
C316 Stainless Steel Vane Assembly (Standard for all pipeline sizes)
Switching Mechanism
W9General Purpose SPST Reed Switch (0.9A @ 110 VAC, 3A @ 28 VDC, 3W min load)
W1General Purpose SPDT Reed Switch (0.9A @ 110 VAC, 3A @ 28 VDC, 3W min load)
L9Low Power SPST Reed Switch for digital PLC/DCS cards (25 Watts max)
L1Low Power SPDT Reed Switch for digital PLC/DCS cards (25 Watts max)
Housing & Enclosure
EFElectronic Switch Housing: Class I, Groups A, B, C, D; Div 1 & 2 (with CS option), 1/2" NPT(F) conduit entry
Accessories & Certifications
CSCSA Certified (US & Canada) Class I Div 1 & 2, Groups A, B, C, D; ANSI/ISA 12.27.01 Single Seal
CKATEX & IECEx Dual Approved: Ex d IIC Flameproof & Ex ia IIC Intrinsically Safe
CLATEX & IECEx Approved: Ex ia IIC T3 Intrinsically Safe
CR3/4" NPT Female Conduit Adapter
CVCanadian Registration Number (CRN) Documentation
HT316 Stainless Steel Terminal Block Housing (NEMA 4X, Class I Div 1 FM/CSA)
NCNACE MR0175 / ISO 15156 Sour Gas Construction (Requires 316SS body)
RB24 VDC Powered DPDT Relay in Explosion-Proof Housing (10A @ 115 VAC)
RC120 VAC Powered DPDT Relay in Explosion-Proof Housing (10A @ 115 VAC)
RR316 Stainless Steel Tag Attached with 304SS Wire
SOR 1520 Model Number Architecture
1520C-F5A-C-W1-EF-CS-NC
1520CModel & Body1520 Series in 316 Stainless Steel
F5AProcess Conn1-1/2" NPT Male Threaded
CVane Material316 Stainless Steel Vane Assembly
W1Switch MechanismSPDT Hermetically Sealed Reed Switch
EFHousingExplosion-Proof Electronic Housing
CSApprovalCSA Certified Class I Div 1/2 Single Seal
NCAccessoryNACE MR0175 Compliance
Technical specifications
Nominal Line Sizes1-1/2" through 6" (38 mm to 150 mm)
Maximum Working PressureUp to 5,000 psi (345 bar) threaded | ASME flange rating for flanged
Operating Temperature-40 °F to 400 °F (-40 °C to 204 °C)
Actuation Flow Rate1.0 FPS (0.3 m/s) minimum liquid velocity
Mounting OrientationVertical Top-Mount Only
Switch MechanismHermetically sealed reed switch with 18" 20 AWG wire leads
Electrical Conduit Entry1/2" NPT Female standard (3/4" NPT Female optional)
Single Seal ComplianceANSI/ISA 12.27.01 Dual-Seal / Single-Seal Certified
Shipping WeightApprox. 6.0 lb (3.0 kg)
Safety Integrity LevelIEC 61508 Certified for SIL 1 and SIL 2 loops
WarrantySOR 5-Year Limited Manufacturer Warranty
Application & Installation Best Practices
The switch must be mounted vertically on top of horizontal piping runs with the flow arrow aligned in the direction of stream travel.
Ensure at least 5 pipe diameters of straight, unobstructed piping upstream and 3 pipe diameters downstream of the vane.
Flanged models require customer-specified nozzle projection length at time of order to ensure correct vane immersion depth.
For low-current PLC/DCS input cards, specify L1 or L9 low-power contacts to prevent contact wetting issues.
Product Overview & Magnetic Operating Principle
The SOR 1520 Electric Flow Switch provides reliable, low-maintenance flow/no-flow detection for liquid and gas lines. Unlike mechanical flow switches that use dynamic shaft seals or bellows prone to fatigue, particulate binding, and leakage, the 1520 utilizes a solid non-magnetic pressure boundary.
As fluid begins flowing through the pipe, the velocity forces the 316SS paddle vane to swing in the direction of flow. This pivots an extension arm containing a permanent magnet upward within the sealed stem. The magnetic field passes through the stainless steel wall to trip a hermetically sealed dry reed switch located in the electrical housing. When flow stops or drops below the minimum velocity (approx. 1 FPS), gravity returns the vane to its rest position, resetting the switch.
Magnetic coupling completely eliminates dynamic seal wear, O-ring degradation, and process fluid leakage into conduit lines
Single seal design per ANSI/ISA 12.27.01 eliminates the need for expensive secondary explosion-proof conduit seal fittings
Low internal resistance and hydrodynamic vane geometry generate negligible pipeline pressure drop
Ideal for pump run-dry protection, cooling water loss alarms, chemical injection verification, and lube oil circulation monitoring
Factory pre-wired with 18" 20 AWG color-coded wire leads for fast, error-free field commissioning
Model Selection & Process Connection Matrix
Threaded 1-1/2" NPT(M) (F5A)1-1/2" NPT Male Threaded Process Connection in 303SS or 316SS (Pressures up to 5,000 psi)
Threaded 2" NPT(M) (F2A)2" NPT Male Threaded Process Connection in 303SS or 316SS (Pressures up to 5,000 psi)
Flanged 2-1/2" (F7C / F7D / F7E)2-1/2" ANSI 150# / 300# / 600# Raised Face Flanges in 316 Stainless Steel
Flanged 3" (F3C / F3D / F3E)3" ANSI 150# / 300# / 600# Raised Face Flanges in 316 Stainless Steel
Flanged 4" (F4C / F4D)4" ANSI 150# / 300# Raised Face Flanges in 316 Stainless Steel
Flanged 6" (F6C / F6D)6" ANSI 150# / 300# Raised Face Flanges in 316 Stainless Steel
Switch Mechanisms & Electrical Options
W9 Switch (General Purpose SPST)SPST Hermetically Sealed Reed Switch: 0.9A @ 110 VAC, 3A @ 28 VDC (3 Watt minimum load)
W1 Switch (General Purpose SPDT)SPDT Hermetically Sealed Reed Switch: 0.9A @ 110 VAC, 3A @ 28 VDC (3 Watt minimum load)
L9 / L1 Switch (Low Power)SPST / SPDT Low Power Reed Switch for digital PLC/DCS input cards: 25 Watts maximum load
RB Relay Option (24 VDC)24 VDC powered DPDT relay in explosion-proof terminal enclosure: 10A @ 115 VAC contact rating
RC Relay Option (120 VAC)120 VAC powered DPDT relay in explosion-proof terminal enclosure: 10A @ 115 VAC contact rating
Model Number Structure & Ordering Tree
SOR 1520 flow switches are configured via a 6-segment ordering nomenclature: [1. Body Material] [2. Process Connection] - [3. Vane Material] - [4. Switch Mechanism] - [5. Housing] - [6. Accessories].
Example Model: 1520C-F5A-C-W1-EF-CS-NC represents 316SS Body, 1-1/2" NPT(M) Connection, 316SS Vane, W1 SPDT Reed Switch, EF Explosion-Proof Housing, CS CSA Certification, and NC NACE MR0175 Compliance.
Step 1 (Body Material)1520B (303 Stainless Steel) | 1520C (316 Stainless Steel)
Step 2 (Connection)F5A (1-1/2" NPT), F2A (2" NPT), F7C/D/E (2-1/2" Flange), F3C/D/E (3" Flange), F4C/D (4" Flange), F6C/D (6" Flange)
Step 3 (Vane Material)C: 316 Stainless Steel Vane Assembly
Step 4 (Switch Mechanism)W9 (SPST 0.9A), W1 (SPDT 0.9A), L9 (SPST Low Power), L1 (SPDT Low Power)
Step 5 (Housing)EF: Electronic Switch Housing (Class I, Groups A, B, C, D; Div 1 & 2 with CS option)
Step 6 (Popular Options)CS (CSA Certified), CK (ATEX/IECEx Ex d / Ex ia), CL (ATEX/IECEx Ex ia), NC (NACE MR0175), HT (316SS Terminal Box), RR (316SS Tag)