PTCR are process temperature control rings. These rings can be used to monitor the consistency of the firing process in a batch or for comparing different batches. Used consistently in the firing process, deviations from a standard are quickly noticed to help prevent out of specification material.

PTCR: What it is: 
The Process Temperature Control Ring, PTCR, is a highly accurate ceramic temperature indicator that records the true heat treatment received by the fired product. PTCR rings take account of both radiated and transferred heat, as well as the effects of temperature over time. It conveniently allows this recorded heat exposure to be expressed as a single number – ring temperature (RT) – which is practical and easy to work with. PTCR rings can be used in both batch and continuous tunnel kilns; they are used in a range of atmospheres. Five different PTCR types are available – in heights of 3.5 and 7.0 mm – covering a range from 850 to 1750°C (1562 to 3182°F). Ring types are identified by color coding and batch and type numbers pressed into the ring.
Originally, PTCR had been developed for in- house application in critical firing processes for advanced electronic ceramic components. Now, the PTCR brings the benefits of easy, accurate kiln temperature measurement to a wide range of industries.

PTCR: How it works: 
When exposed to heat in the kiln, the PTCR ring contracts – and continues contracting as the top temperature is maintained over time. The degree of contraction is almost linear over the complete operating range of the PTCR, providing a practical measure of the accumulated heat to which the ring – and the fired products – have been subjected. The amount of contraction – the amount by which the ring diameter has shrunk – is measured with a numerical or digital micrometer. This measurement can be converted to ‘ring temperature’ for ease of comparison and correlation to the firing process.

PTCR: Quality you can rely on. 
PTCR is recognized for its accuracy and reliability, and its recently improved technology now offers an unsurpassed accuracy guarantee: a minimum variation of 3°RT. ** This reliability is based on a stringent manufacturing process. PTCR rings are made from a mix of high-grade materials. Their composition is fine-tuned through advanced Design Of Experiments- (DOE) techniques, and the production process itself is controlled by Statistical Process Control. In fact, the entire PTCR manufacturing facilities have been awarded the internationally recognized ISO 9001:2000 and ISO 14001 quality certification.
(for each product, do we want to put a background color of the ring?)

PTCR ring Dimensions: 
ending in L (low) are 3.5mm H x 20mm outer diameter x 10 mm inner diameter
ending in H (high) are 7mm H x 20mm outer diameter x 10 mm inner diameter

PTCR  rings are stamped with product name and batch
Temperature                    Product name
range
850  -1100C                       ETH & ETL            Rings are light green in color before firing
1562-2012F

970  -1250C                       LTH & LTL            Rings are red in color before firing
1778-2282F

1130-1400C                        STH & STL           Rings are green in color before firing
2066-2552F

1340-1520C                        MTH & MTL           Rings are crème in color before firing
2444-2768F

1450-1750C                        HTH & HTL            Rings are white in color before firing
2642-3182F

Special micrometer mounted on a stand for consistent reading of fired rings.