ASME SA516 Gr.70N STATIONARY TUBESHEET
Fixed tube plate heat exchanger refers to a shell and tube heat
exchanger in which the tube plates at both ends of the tube bundle
are fixedly connected to the shell by welding. After the tube plate
and the shell are welded, it can also serve as a flange and be
connected to the pipe box flange with bolts. The advantage is that
the structure is simple and the inner diameter of the shell
required is the smallest while ensuring equal heat transfer
surfaces.
Tube sheets are key components of various heat exchangers and
shell-and-tube vessels. Its main purpose is to provide support and
sealing to the tube bundle. Within cylindrical or rectangular
tubes, there are different types of tubesheets, each type designed
for a specific application. Here are some common segment types and
their detailed descriptions:
1.Fixed tube sheet: Description: The fixed tube sheet is fixed in
the shell of the heat exchanger and welded or welded into the hole
of the fixed tube sheet. They will not move relative to the tube
sheet and the expansion between the tubes and the shell is very
small.
2. Floating tube sheet:
Description: The design of the floating tube sheet allows the tube
bundles to expand and contract freely with temperature changes. The
tube sheet is not connected to the shell by direct welding:
however, it can be moved within certain limits. Use hs desien when
stgticat temptre vanaton is present to help prevent damage to pipes
and pipe-to-tubesheet joints.
3. U-shaped tube bundle:
Description: In a U-tube bundle heat exchanger, the tubes are bent
into a "shape." The ends of the U-shaped tubes are fixed or welded
to a single tube sheet. This configuration is typically used in
applications where thermal expansion and contraction need to be
accommodated, but the connector needs to be removed for
maintenance.
4. Floating head tube plate:
Note: In some shell and tube heat exchangers, the other end is
closed by a floating head tube heat exchanger, and one end of the
shell is closed by a fixed tube sheet. The floating head can move
axially to accommodate the thermal expansion and contraction of the
tube. This design is common in Rappe heat exchangers.
5.Fixed tubesheet (with expansion joint description) If the
temporary connection between the tube and shell is important and a
floating tubesheet may not be practical, expansion joints may be
incorporated into the design of the fixed tubesheet. These
expansion joints allow a certain amount of movement while
maintaining a strong connection between the tube and tubesheet. The
choice of tubesheet type depends on a variety of factors, including
the specific application, temperature and pressure requirements,
and the need to accommodate thermal expansion and contraction.
Proper selection and design of tubesheets is critical to ensuring
efficient and safe operation of heat exchangers and pressure
vessels
The characteristics of fixed tube plate heat exchanger are:
1. The bypass seepage is small;
2. Forgings are used less and cost is low;
3. No internal leakage;
4. The heat transfer area is 20% to 30% larger than that of the
floating head heat exchanger.
The disadvantages of fixed tube plate heat exchangers are:
1. The temperature difference between the shell and the pipe wall
is large. When t ≥ 50°C, an expansion joint must be installed on
the shell;
2. Temperature difference force is easily generated, and
temperature difference stress is easily generated between the tube
plate and the tube head, causing damage;
3. The shell side cannot be cleaned mechanically;
4. After the pipes are corroded, they will be scrapped together
with the casing, and the equipment life will be short.
