Barksdale DPD1T-A150SS-LV Differential Pressure Switch

Barksdale DPD1T-A150SS-LV Diaphragm Differential Pressure Switch

The Barksdale DPD1T-A150SS-LV is an industrial-grade, single-setpoint housed diaphragm differential pressure switch engineered for critical differential monitoring across liquid, gas, and hydraulic systems. Utilizing a 17-7 PH stainless steel sensing diaphragm with Viton® elastomer seals, this unit provides exceptional repeatability (±0.5% of adjustable range) and high resistance against hydraulic pulsing and line transients.

In marine engineering and heavy industrial plant duty, the switch is deployed across main engine lube oil duplex filter systems, heavy fuel oil (HFO) separators, ballast water pump manifolds, and marine boiler feedwater differential lines. The rugged anodized die-cast aluminum enclosure meets NEMA 4 / IP65 water-tight ingress standards, guarding the SPDT microswitch and terminal block against saline atmospheres and severe engine-room vibration.

Model Details

• Manufacturer: Barksdale Control Products
• Model Code: DPD1T-A150SS-LV
• Manufacturer Part Number (MPN): DPD1T-A150SS-LV
• Base Configuration: Single Setpoint Housed Diaphragm Differential Switch (DPD1T)
• Switch Element: Class A SPDT Snap-Action Limit Switch
• Adjustable Range Code: 150SS (1.5 to 150 psi / 0.10 to 10.3 bar differential)
• Diaphragm Material: 17-7 PH Stainless Steel
• Modifier Option (-LV): Low-Voltage / Low-Vent specific configuration with specialized internal sealing

Key Features

1. Heavy-Duty Diaphragm Sensor: 17-7 PH stainless steel sensing element with Viton® wetted elastomers for chemical resistance and fatigue life.
2. Tamper-Proof External Adjustment: External calibrated hex-screw mechanism enclosed under a protective security cap.
3. High Working & Proof Pressures: Operating differential up to 150 psi (10.3 bar) with an overpressure proof rating of 300 psi (20.4 bar).
4. Robust Marine-Grade Enclosure: Anodized die-cast aluminum housing engineered to NEMA 4 / IP65 ingress protection.
5. High Electrical Capacity: UL/CSA-rated SPDT snap-action contacts handling 10 A @ 125/250 VAC and 3 A @ 480 VAC.

Applications

• Duplex Strainer & Filter Differential: Monitoring clogs and Delta-P rise across marine engine lube oil, MGO/HFO filters, and hydraulic power units (HPUs).
• Centrifugal Pump Loss-of-Prime & Flow Verification: Detecting differential loss across sea water cooling and ballast pump suction/discharge manifolds.
• Marine Air Handling & Ventilation Systems: Air filter clog detection in machinery space supply fans and accommodation HVAC circuits.
• Boiler & Feedwater Economizer Delta-P: Monitoring differential backpressure in steam generation and condensate return lines.
• Separation & Purification Modules: Fuel oil purifier bowl feed differential and water-in-oil seal monitoring circuits.

Compatible Equipment Systems

• Marine Engine Lube Oil Skids: Wärtsilä (Vasa 32, 34SG, 46), MAN B&W (S50/60/70MC, ME series), Caterpillar Marine (3500, C280, C32).
• Duplex Filtration Systems: Boll & Kirch (Type 4.46, 2.05), Hydac, Parker Racor, Pall Marine.
• Hydraulic Power Units (HPUs): Rexroth, MacGregor deck machinery units, Rolls-Royce steering gear packs.

Part Number Cross-References & Equivalent Codes

• Barksdale: DPD1T-A150SS, DPD1T-M150SS, DPD1T-A150SS-FX, 0401-086
• Schneider / Telemecanique Interchange: XML-K / XML-B differential equivalents (retrofit)
• Custom OEM Cross-Reference: Wärtsilä P/N 874 122, Alfa Laval P/N 546981-01

Frequently Asked Questions

What is the maximum proof pressure for the Barksdale DPD1T-A150SS-LV?

The unit carries a maximum differential proof pressure rating of 300 psi (20.4 bar). Exceeding this limit can distort the 17-7 PH stainless steel diaphragm and shift calibration setpoints permanently.

Can this switch be used for differential vacuum service?

Yes. The DPD1T diaphragm construction supports vacuum differential measurements. When adjusting for vacuum differential, counterclockwise adjustment decreases the vacuum setpoint, while clockwise adjustment increases the vacuum differential value.

What causes the switch contacts to chatter in engine lube oil systems?

Contact chatter is almost always caused by positive displacement pump pulsations or severe acoustic resonance in the impulse tubing. Install snubbers, needle restrictors, or a pulsation dampener loop on the 1/8″ NPT impulse connections to stabilize fluid dynamics against the sensing diaphragm.

How does the -A limit switch differ from the -M option?

The standard -A limit switch is optimized for AC circuits (10 A @ 125/250 VAC). If your marine automation system operates on 24 VDC / 125 VDC control loops with significant inductive loads, the -M limit switch (fitted with magnetic blowouts) or the -GH switch (with gold-plated contacts) should be specified to prevent contact arc degradation.

How do I clean the sensing chamber if media contains sludge or particulate?

Isolate the manifold and depressurize the lines completely. Remove the bottom flange screws to inspect the diaphragm chamber. Flush solely with clean solvent and a non-abrasive soft cloth. Do not use metal scrapers, screwdrivers, or sharp instruments against the 17-7 PH stainless steel diaphragm surface.