While  the  diaphragms with  rubber-coated fabric  are made  by shaping  the fabric, the
reinforced diaphragms are made by moulding and attaching a fabric insert to the rubber.
Cervellati can  produce diaphragms with  rubber and fabric  insert which best suit to the
customers’ needs.  Thickness and shape can vary according to the client’s drawing, so
that no additional cardboard gaskets are required.

The  illustrations  from Fig.1 to Fig.4  show  some  characteristic shapes  of reinforced
diaphragms.
The concave diaphragm (Fig. 1) must be assembled to take  on a configuration similar
to the convoluted diaphragm (Fig. 2). The convoluted diaphragm, however, is moulded
into the same shape that it will take during the assembly phase.

Advantage of the reinforced diaphragms, compared to the diaphragms with rubber-coated fabric:

- Better height-to-diameter ratio, therefore longer travel;
- More efficient seal;
- Greater resistance to pressure;
- Possibility of using all types of rubber and fabric inserts;
- Lower sensitivity and greater hysteresis;
- The ply is not positioned at centre, as with the rubber-coated fabric, but on the outside
surface.  As a result, the differential pressure will always be  applied to the side of the
rubber.

Disadvantages:

-  Lower sensitivity and greater hysteresis;

- The ply is not positioned at centre, as with the rubber-coated fabric, but on the outside
surface.  As a result,  the differential pressure  will always be applied to the side of the
rubber.

Diaphragms function:

The function of these diaphragms,  and therefore their travel,  stems from the "rolling" of
the convolution, which will be sustained inside by the pressure.  As a result, the thrust of
the caps  or  the piston forces  the diaphragm  to perform  an axial movement due to the
membrane rolling along the generating line of the convolution (Fig. 5 - 6).
Diaphragms operating  according to this principle  are also known as rolling diaphragms.