NOSHOK 628 Intrinsically Safe Hammer Union Pressure Transmitter

Intrinsically safe hammer union transmitter for wellsite pressure to 20,000 psig

The NOSHOK 628 Series is a hammer union pressure transmitter for high-pressure oilfield work. A 2 inch wing union (figure 1502) connection screws straight into frac iron, choke and kill manifolds and cementing lines, and a stainless steel housing with Inconel X-750 wetted parts takes ranges from 0-5,000 psig up to 0-20,000 psig. The output is 4-20 mA, 2-wire. Every sensor ships with a Certificate of Calibration according to the datasheet.

The unit carries Canadian Standards Association approval for intrinsically safe and non-incendive use as printed in the datasheet, and optional accessories include a carrying handle and an electrical connector cage.

628 specification

Order code explained

Example in the datasheet: 628-5000-1-1A-14-3-CH means series 628, 0-5,000 psig, accuracy code 1 (+/-0.25%), output code 1 (4-20 mA), wiring code A, process connection 14 (2 inch wing union figure 1502), electrical connection 3 (6-pin bayonet MIL-C-26482) and option CH (carrying handle).

Selection and use

• Check the proof ceiling: proof pressure is 1.5 x full scale with a 22,500 psi maximum, so 15,000 and 20,000 psig units are capped at that figure.
• Match the wiring code to your barrier or readout; the standard H code leaves the case ground not connected to pins E or F.
• Use an intrinsically safe barrier or power supply suitable for the entity parameters in the CSA certificate (confirm with the maker).
• IP67 applies depending on the electrical connection, so seal the connector or use the cable gland version in washdown or rain.

Applications in Oman and the GCC

The datasheet lists acidizing, choke and kill manifolds, fracturing and cementing, mud logging and mud pumps, oil field and offshore work and well head measurement. In GCC drilling and well service the hammer union format lets crews monitor treating pressure without welding or special adapters. Ambient and media limits run from -40 F to 185 F, which covers desert heat but not hot-oil or steam service.

Working with a high-pressure hammer union sensor

A 20,000 psig transmitter is a safety-critical part, so treat the datasheet limits as hard limits. Proof pressure is 1.5 times full scale and burst pressure is 3 times full scale, with both capped at 22,500 psi, which means the 15,000 and 20,000 psig versions have a reduced margin compared with the 5,000 psig unit. The 2 ms response time and 10 million load cycle service life are the printed figures for pulsating pump pressure, so a mud pump or frac pump pulse is within the sensor design. The six pound weight and wing union mounting mean the sensor hangs from the iron, so support the cable or connector cage to avoid side loads on the union. Calibration certificates accompany every sensor, and the repair program named on the NOSHOK page covers hammer union units. Keep the carrying handle fitted for transport so the connector is not used as a lifting point.

Selection and installation notes

A pressure instrument is selected from the pressure range, the process media and the connection. Choose a range so that the normal operating pressure lies in the middle of the scale, check that the wetted materials suit the fluid, use the correct seal and thread, fit an isolation valve or snubber where pulsation or surges occur and mount the instrument where it can be read and serviced. Never exceed the overpressure limit on the data sheet, and keep a record of calibration.

In a hazardous area, check the certification marking against the zone, gas group and temperature class of the site, use cable glands and conduit seals approved for the protection method, and install intrinsically safe equipment only with approved barriers or isolators. Do not open the enclosure when the area is live.

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 our pressure instrumentation category and the NOSHOK 621/622 explosion-proof transmitter. The official datasheet is attached; please confirm range, wiring code and connector with Seven Star LLC before ordering.