Referthermo
The development of REFERTHERMO started in 1991 by the Juridical Foundation of Fine Ceramic Center (JFCC) with the purpose of standardizing the test/evaluation method of fine ceramics. 5 models have been developed so far for different temperature zones.
Referthermo
Referthermo is a reliable thermal history sensor that enables the user to simpley and precisely control the firning process.
Firing of ceramics is typically performed by monitoring the furnace's temperrature profile.However management of the entire thermal history of a ceramic is necessary if firing conditions are to be accurately controlled,since these can vary with furnace type and atmosphere.
Referthermo is a series of practical reference materials whose composition,grain size distribution and green body density are precisely controlled.Optimum firing conditions can be quickly and simply determined by co-firing a Referthermo tablet with the ceramic products and measuring the tablet's length after shrinkage.
Advantage of use
-
Steady-state firing conditions are usually maitained by measuring a furnace's temperature with a thermocouple or optical pyrometer, but these thermal sensors cannot take into account important factors apart from temperature. Furthermore, it is well known that calibrating such measuring instruments is itself a difficult task.
Seger cones and Orton cones are similar thermal history sensors to Referthermo. These cones are pyramidal in shape, but since the firing conditions are indicated by the degree of sagging of the tops of the cones, a precise quantitative evaluation of the temperature is not possible.
Referthermo,however,uses shrinkage phenomena to quantitatively determine the amount of "heat-work", so it is much sensitive to abnomal conditions.This sensitivity can be improved further by using a management chart or similar method.
Used regularly as a temperature monitoring system,Referthermo can be considered to be a thermal history sensor that promptly reveals abnormalities in the firing cycle.
How to use
1) Set the referthermo at the appropriate place.
(2) firing
(3) holding temperature
(4) measurement
Temperature ranges
| Type | Temperature ranges（℃） | Temperature ranges（℃） |
|---|---|---|
| H | 1400〜1700 | ±10 |
| M | 1200〜1500 | ±10 |
| L | 1050〜1300 | ±10 |
| L1 | 800〜1150 | ±15 |
| L2 | 600〜900 | ±15 |
Selecting
If a holding time of two hours is used and the atmosphere is air, the choice of Referthermo can be made using the above table. For example, if the firing temperature is 1350℃, type M would be recommended, and if 1150℃,type L.
In the case of a firing temperature of 1250℃, types M and L should be tested under the user's actual firing conditions, and the type that gives the closer measurement to the median value of the conversion table selected.
Next we consider a situation where Referthermo is to be heated in air but for different holding times, If the holding time is longer than two hours, then a higher temperature type of Referthermo may be appropriate; conversely , if the holding time is less than two hours,a lower temperature type of Referthermo may be better. For example, for a holding time of 30 minutes at 1250℃, type L would be a better choice than type M.
When firing in a atmospheres other than air, it is necessary to estimate the relation between holding time and temperature by performing test runs under the actual firing conditions.
Contuct us
Businessport Co.,Ltd.（products department）
(Postal Code) 607-8085
8-6,Dounomae-cho,Takehana,Yamashina-ku,Kyoto-shi Japan
TEL:(+81) 75-501-1800 FAX:(+81) 75-502-8833
