AMETEK Land Gold Cup Reformer Tube Reference Pyrometer

Gold Cup reference pyrometer for reformer tube surface temperature

The AMETEK Land Gold Cup is a water-cooled, hand-held reference thermometer used to measure the true surface temperature of reformer and other fired-heater tubes. A gold-plated hemisphere is pressed against the tube. Inside it, infrared energy is reflected many times before it reaches the detector, so the reading is close to black-body conditions and does not depend on a guessed emissivity. The brochure states that the energy is reflected at least 12 times, which pushes the effective emissivity towards 1.00.

It is not meant to replace permanent temperature measurement. Its purpose is to give plant engineers a trusted number so that portable thermal imagers, infrared thermometers and furnace pyrometers can be checked and corrected. Seven Star LLC supplies it in Oman and the GCC as an independent supplier in Muscat, for refineries, petrochemical plants and fertiliser sites that run fired heaters.

Gold Cup technical specifications

How the gold hemisphere removes emissivity and background errors

Ordinary infrared thermometers have two big uncertainties inside a furnace: the unknown emissivity of the tube surface and the hotter radiation reflected from the furnace walls and flames. The hemisphere deals with both at once. The hemisphere touches the tube and shields the measurement area from the hotter surroundings. Its highly reflective gold coating bounces the tube’s own radiation around the cavity so that the optical fibre sees something very close to a black body.

A silicon detector at 1.6 µm (short wavelength) then measures the radiation, and the battery-powered display unit converts it to temperature. The display also powers the thermometer, so no mains supply is needed at the furnace.

Using the probe on a fired heater

The brochure describes the working method. The probe is first connected to its cooling water supply and to the display unit. It is then inserted through an inspection port into the furnace and the gold cup is touched onto the tube, with the probe level and aligned to the centre of the tube. The reading is recorded straight away, before the tube has time to cool under the probe.

• Check the cooling water supply is below the 3 bar limit and that hoses are fitted to the 3/8 in BSP connections before opening the port.
• Align the probe level with the tube centre; poor contact lets background radiation in and reduces the benefit of the cavity.
• Record the display reading immediately and note the tube position and time.
• Remove the probe and let it cool before the next tube; keep the dry protective cover on during transport.
• Compare that reading with the reading of the portable imager or pyrometer being checked and derive the correction.

Water-cooled probe compared with the modular version

AMETEK Land also offers a modular version, which uses the same gold-hemisphere principle in a probe that can be assembled to different lengths and bent angles and which is cooled with air rather than water. The classic version described here is the water-cooled version with a fixed probe and a 6.9 kg weight. The table shows how the two differ in the details published by the manufacturer.

What to confirm before ordering

• Cooling supply. This probe needs clean cooling water at the furnace. If only compressed air is available on the platform, the modular air-cooled version is the better fit.
• Port and tube access. Check port size and the distance from the port to the tube row you want to measure.
• Temperature range. 300 to 1300 °C covers most reformer tube duties, but confirm the highest metal temperature in your heater.
• Calibration. UKAS calibration and a cooling control panel are available through the manufacturer; request them with the order if your audit needs a certificate.
• Spares. Plan a spare 9 V battery and a case; they are handled and stored like any other portable test instrument.

Care and handling

The gold surface is what makes the reading accurate, so keep it clean and avoid contact with anything other than the tube. The probe is sealed to IP67, but the rubberised case and dry protective cover are there to protect the head between measurements. Ensure the cooling water is switched on before the probe enters the heat and left on until it has come out and cooled. Store the instrument in its case with the battery removed if it will not be used for a long time, and arrange recalibration with the manufacturer on the interval your quality system requires.

Typical applications in Oman and the GCC

Steam methane reformers in ammonia, methanol and hydrogen plants, and ethylene or refinery fired heaters, operate close to the metallurgical limit of their tubes. Overestimating tube temperature wastes capacity, while underestimating it shortens tube life. Operators in the Gulf use surface checks during turnarounds and as part of regular campaigns to calibrate the imagers and infrared thermometers that they use in between. High ambient temperature outdoors and strong furnace radiation also make an emissivity-independent reference useful, because it lets different technicians arrive at the same number.

Information to send with an RFQ

• Furnace type, tube diameter and expected tube metal temperature.
• Port size and probe reach needed.
• Cooling water availability and pressure (or air only).
• Whether a cooling control panel and UKAS calibration are required.
• Quantity and delivery location in Oman or the GCC.

Documents and quotation

The manufacturer brochure with the specification sheet is attached on this page.

Send us the part number, your application and any options, and Seven Star LLC will confirm availability and lead time for delivery in Oman and the GCC.