IMPROVING THE LINING OF CARS
USED IN SHORT TUNNEL FURNACES
T. F. Baranova,
I. B. Mal’kov,
and S. A. Valiakhmetov
Translated from Novye Ogneupory,No.12,pp.3–5,December, 2015.
Original article submitted October 8, 2015.
An improved design of lining has been developed for the cars of short PG-30 tunnel furnaces, which are used
to fire ceramic tooling: crucibles, cores, and molds for casting products made of heat-resistant alloys. The top
part of the refractory layer that is installed on the heat-insulating layer consists of two superimposed panels.
All of the panels except for the top panel contain interrupted holes (a total of 44 such holes) that are arranged
in staggered fashion and open onto the panels’ main surfaces. The top panel contains blind holes (totalling 22).
In assembling the refractory layer, the ends of the panels are connected to one another in such a way that the
holes their surfaces are coaxial. The top panel is positioned so that the surface without holes faces upward and
the holes on the other surface face downward. The box-inserts that hold the ceramic products which are to be
fired are placed on the top panel. Such a design of car significantly reduces its weight while also increasing its
service life. Durability is improved in particular for high-speed operation of the cars, such as in the firing of
foundry molds for casting nickel alloys.
Keywords: car for tunnel furnace, car lining, speed, panel.
It is known that the design of the cars in furnaces used to
fire ceramic products should ensure minimal heat losses dur-
ing the heat treatment and highly reliable operation of the
furnace over a long period of service, with allowance for the
temperature regime used for firing. These cars usually have a
metal base and a lining composed of two parts: a heat-insu
lating layer of material as the lower part and a refractory
layer of material as the upper part.
The presence of fibrous materials and products in the
heat-insulating lower layer ensures that the lining will have a
low thermal conductivity and will compensate for the ther
mal expansion of the lining’s higher layers, thus protecting
the car from deformation. The refractory layer (bottom) often
consists of an assembly of elements — slabs or specially
shaped blocks [1 – 4]. When the bottom is made up of such
elements, it is important to consider the method that is used
to attach them to one another. The chosen method should
keep the assembled elements from shifting, moving apart, or
The assembled elements of the lining are subjected to
thermal and dynamic loads while the car is moving in the
furnace. These loads are greater, the smaller the elements, the
lower the heat resistance of the constituent material, and the
less strongly the elements are connected to one another. For
these reasons, the reliability of the floor of such cars and its
service life are both in decline.
A description was presented in  of a lining for a tun
nel-furnace car whose top layer is composed of courses of
flat refractory products that are connected to each other
about their perimeter by lap joints formed with the aid of
projections located on their lateral faces. To keep the prod
ucts from separating from one another, the joints between
them should be formed with a certain precisely determined
value for the included angle. This is one drawback of the de
sign, since even a slight deviation of this angle in one direc
tion or the other will cause the entire seating area of the car
to come apart — especially at high firing temperatures.
A different configuration of a car for use in short tunnel
furnaces was examined in . The refractory part of the lin
ing of this car consists of ceramic supports and refractory
panels and blocks. The ceramic supports, containing a
through hole having the same cross as the projections on the
metallic base, are mounted on the projections through the
Refractories and Industrial Ceramics Vol. 56, No. 6, March, 2016
1083-4877/16/05606-0574 © 2016 Springer Science+Business Media New York
”Salut” Scientific-Technical Center for Gas Turbine Engineering,