Palmer Wahl 1050 Direct Drive 5 Inch Dial Thermometer

A direct-drive filled-system dial thermometer with a rigid stem

The Palmer Wahl Model 1050 is a 5 inch dial thermometer with a rigid stem, a half inch NPT fitting and a quarter inch diameter bulb. The datasheet describes it as a filled-system thermometer with a double-wound Bourdon coil, and calls it a superior alternative to bimetallic thermometers. It is built in Asheville, North Carolina, to order from a four-step code.

The key design point is the direct-drive movement. The pointer shaft turns directly from the centre of the coil, which removes the sector and pinion mechanism found in many dial thermometers. The datasheet says this keeps the instrument responsive to temperature change and accurate over many years, because there is no multiplying linkage to wear.

Features

• Polished 316 stainless steel case with a 5 inch (127 mm) dial, black graduations and numerals on a white aluminium dial and a tapered-tip black pointer that can be adjusted for calibration.
• Stainless steel bezel ring and glass cover, gasket sealed, with an optional Plexiglas cover.
• Liquid-actuated system below 500 F, filled with a non-toxic, odorless, non-flammable organic liquid; mercury-actuated systems are used for ranges above 500 F and on request.
• Case-compensated system with the double-wound direct-drive Bourdon coil.
• Adjustable all-angle case that is locked at the best reading angle during installation; an optional centre back connected case lets the head be rotated after installation.
• Standard 304 stainless steel half inch NPT fixed fitting, with an optional 7/8 inch 22 swivel nut or 316 stainless steel fitting.

Model 1050 specifications

Order code and range selection

The part number is built in four steps: case style, stem length, temperature range, then options. Stem lengths are 4, 6, 9, 12, 15, 18 and 24 inches; longer stems are available by calling the maker. Ranges above 500 F or 260 C need a minimum stem length of 4 inches on all-angle models and 6 inches on back connected rigid models. The datasheet gives this example: 105090/600F(SS) is a 5 inch dial, 9 inch stem, 0 to 600 F mercury-actuated range, 316 stainless steel fitting.

Options are F&C dual scale, (PC) Plexiglas cover, (S) 7/8 inch 22 swivel nut fitting and (SS) 316 stainless steel fitting. Dual scale Fahrenheit and Reaumur ranges of 0 to 240 F and 0 to 150 F are listed as call for availability.

Installation and selection notes

• Match the range to the process: a mid-scale operating point gives the best readability, and the 5 degree divisions above 400 F are coarser than the 1 degree divisions on the lowest ranges.
• Specify stem length from the thermowell insertion depth. The datasheet measures it from half an inch up on the threads to the bulb tip.
• Fit it to a bimetal-type thermowell with a 0.260 inch bore. A separate thermowell is not included in the datasheet order code.
• Use the centre back connected 1050AR when the head must be turned after installation, and the all-angle 1050 when it can be set once and locked.
• Confirm with us if mercury-filled bulbs are acceptable for your shipping destination, because the datasheet says availability below 500 F depends on local rules.

Applications in Oman and the GCC

The datasheet lists chemical and petrochemical plants, hazardous environments, process engineering, pulp and paper, water treatment, pneumatics, compressor controls, pump protection and shipping, together with power plants, breweries, canneries and HVAC equipment. In the Gulf this translates into utility, desalination, district cooling and process skids where a readable local temperature indicator on a thermowell is needed beside the transmitter. The 316 stainless case suits coastal humid sites.

Selection and installation notes

A thermometer or temperature transmitter is selected from the range, the stem or bulb length, the connection and the ambient conditions. Fit it in a thermowell of the right bore and length so the sensing element reaches the flow, fill the well with heat-transfer paste where the maker advises, keep the cable or case clear of heat and vibration and check the reading against a reference instrument at commissioning and at regular intervals.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Related items and documents

See more temperature instruments from our range. The Palmer Wahl datasheet is attached to this page. Seven Star LLC can quote the exact stem length, range and options.