Barksdale B1S Series Bourdon Tube Pressure Switch

A Bourdon tube switch for pressures up to 18,000 psi

The Barksdale B1S belongs to a four-model Bourdon tube series: B1S (single setpoint, stripped), B2S (dual setpoint, stripped), B1T (single setpoint, housed) and B2T (dual setpoint, housed). A 316 stainless steel Bourdon tube and process fitting senses pressure and drives a single-pole double-throw snap-action switching element, with a tamper-proof external adjustment. Barksdale states an accuracy of plus or minus 1 percent of the adjustable range, and the series reaches adjustable setpoints up to 18,000 psi, well above the compact and diaphragm switches in the same catalogue.

The stripped versions have 21 inch free leads and are intended for installation inside another enclosure or a panel; the housed versions have an anodized aluminum NEMA 4 enclosure with an internal terminal strip and a conduit connection. Barksdale lists oil and gas, medical, mining, compressors, power plants, water pumps, hydraulic power units, pneumatic devices and general industrial uses.

Technical specifications

Range codes and proof pressure

Range codes 12, 32, 48, 65, 120 and 180 are the nominal top of the range in hundreds of psi. Proof pressure is higher on housed models than on stripped models, so state which body style you need. Ranges as printed on the datasheet (subject to change per the footnote):

Ranges 120 and 180 are not available with any agency approval. Deadband values apply with the standard limit switch; the S class limit switch has an adjustable differential knob, and an optional adjustable-deadband model lets you set the decreasing setpoint first and then widen the differential with the microswitch wheel.

Ordering code, limit switch and options

The datasheet example is B1T -AA 180 SS: series, limit switch letter, range code and SS for the stainless Bourdon tube. Limit switch A is rated 10 A at 125/250 VAC and 3 A at 480 VAC and is standard on ranges 12, 48, 65, 120 and 180; H is 10 A at 125/250/480 VAC with 0.1 A at 125 VDC and is standard on range 32; M adds 0.5 A at 125 VDC; S is 15 A at 125/250/480 VAC with adjustable differentials; GH is a gold-contact type for 1 A at 125 VAC. Options are -CS for UL and CSA approval (housed models only, maximum 300 VAC), -FX for NEMA 4X (housed only), -Z1 oxygen cleaned, -Wxxx extra lead length in inches and -Sxxx factory preset. The process connection is 1/4 inch NPT for ranges 12, 32 and 48 and a 1/4 inch tube fitting for 65, 120 and 180, or option -P4 for 1/4 inch NPT female on the three highest ranges.

Installation and what to confirm before ordering

Operating temperature is -40 to 165 F (-40 to 74 C). To change a setpoint, remove the protective hex cap or the housing cover; turning the adjustment screw clockwise lowers the setpoint and counterclockwise raises it. Shipping weight is about 1.5 lb for stripped and 2.5 lb for housed models. Confirm the fluid against 316 stainless steel, the proof pressure for your peak (including pulsation), single or dual setpoint, stripped or housed body and the load for the limit switch. The datasheet notes UL file E42816 and CSA class 3231 02 for the optional approvals. The attached file is the two-page Barksdale datasheet (bulletin S0076-E); related switches are in pressure instrumentation. Send the full code and quantity for a quotation.