Heat Exchanger Types and Arrangements

Vahterus products waiting for shipping

Heat exchangers exists in many various arrangements and types. The choice of arrangement of the heat exchanger is influenced by:

  • the applicable medium;
  • the applicable cleaning system;
  • preference to remove/change plate pack.

Vahterus Plate & Shell Heat Exchangers are available as fully welded, openable and compact solution.

To read more about the technology behind Plate & Shell Heat Exchanger - read here.

Table of Contents

  1. Fully welded version
  2. Openable version
  3. Compact version
  4. Number of passes
  5. Mounting direction
Vahterus Plate & Shell Heat Exchanger Fully Welded Unit
Vahterus Plate & Shell Heat Exchanger fully welded version

Fully welded version

The core of the Vahterus Plate & Shell Heat Exchanger (PSHE) is a fully welded plate pack enclosed in a strong shell structure, which eliminates the need for a gasket. It withstands extremely high pressure, stress variation and thermal shocks. Like the plate pack, the surrounding shell is fully welded. The plate pack and shell are not, however, welded together, which allows them to expand and contract with heat variation. The plate pack consists of circular plates, which guarantees even distribution of stress. The structural properties of our fully welded heat exchanger also make them durable, easy to maintain and energy-efficient.

Vahterus Plate & Shell Heat Exchanger Fully welded execution
Vahterus Plate & Shell Heat Exchanger Fully Welded execution (1 = end plate; 2 = plate pack; 3 = flow directors; 4 = mantel / shell)

Additionally, our PSHEs are 60–70% smaller than traditional shell & tube heat exchangers. Due to their compactness, PSHEs are an excellent choice for retrofitting. PSHEs are also light, and thus easy to transport and install. They can be used in locations where weight limits apply, and require no additional support structures.

Vahterus Plate & Shell Heat Exchanger Openable
Vahterus Plate & Shell Heat Exchanger Openable version

Openable version

The Vahterus Plate & Shell Heat Exchanger Openable offers increased flexibility, allowing the plate pack to be pulled out from the shell for inspection or mechanical cleaning. This is achieved through the flanged and bolted shell construction. The cassette-type plate pack allows for a quick and easy removal and refitting, thus ensuring that process downtime is kept to a minimum. The customer’s knowledge and experience of the process is essential when conceiving the design.

Vahterus Plate & Shell Heat Exchanger Openable Execution
Vahterus Plate & Shell Heat Exchanger Openable execution (1= end plate flange; 2 = gasket; 3 = plate pack; 4 = flow directors; 5 = shell flange; 6 = shell)

As part of the design, fouling is taken into consideration. We can customise efficient heat exchanger cleaning systems for even the toughest of environments. Further access for cleaning can be gained with the stretchable model, the plate pack designed for the heaviest fouling.

Compact version

Vahterus Plate & Shell Heat Exchanger Compact Execution
Vahterus Plate & Shell Heat Exchanger Compact execution (1 = end plate; 2 = Z-plate; 3 = plate pack; 4 = flow directors; 5 = shell; A = shell side flow; B = plate side flow)

Number of passes

The choice of single or multi-pass design is influenced by the following parameters:

  • pressure loss and even distribution;
  • available space for the connections on the shell;
  • requirement for purging and draining;
  • the application.

In some circumstances it is not physically possible to use a multi-pass arrangement, for example in specific evaporating and condensing processes. With liquids and gases there are more possibilities for multi-pass applications.

The choice of a closed (fully welded) or openable version is influenced by:

  • the applicable medium;
  • the applicable cleaning system;
  • preference to remove/change plate pack.

In refrigeration, 99% of units delivered are the fully welded type.

Matti-Kontu-and-Valtteri-Haavisto

Mounting direction

The mounting direction of the heat exchangers will normally be decided by the process. Usually the shell is installed horizontally with the plates arranged vertically. Some important considerations that may influence the mounting direction are (among others):

  • the natural direction of gas or liquid (or a mixture) should be followed where possible to prevent blocking the heat exchanger;
  • plates installed horizontally are not self-draining and there is the possibility that, under low velocity conditions, process media (oil, condensed liquid, dirt etc.) may remain on the plate surface, fouling the heat exchanger and reducing performance;
  • direction of system main lines.

The figures below show some examples of different possible designs. The final design is, of course, dependent on the specific nature of each application.

Fig 3 1 Mounting Direction For Fully Welded Units Vertical
Horizontal mounting direction for Vahterus PSHE Fully Welded units (1= proposed purge point; 2 = proposed drain point; H = single-pass on shell side and plate side; I = multi pass on shell side and plate side)
Fig 3 1 Mounting Direction For Fully Welded Units Horizontal
Vertical mounting direction for Vahterus PSHE Fully Welded units (1= proposed purge point; 2 = proposed drain point; A & B = single-pass on shell side and plate side; C = single-pass on shell side and double single-pass on plate side; D & E = multi-pass on plate side; F & G = multi-pass on shell side)
Mounting direction for Vahterus openable heat exchangers Fig 3.2
Mounting direction for Vahterus PSHE Openable units (1= proposed purge point; 2 = proposed drain point; J = single-pass on plate side; K = two-pass on plate side; L = single-pass on shell side; M = double single-pass unit on shell side; N = two-pass on shell side)
Vahterus fully welded plate packs in production

Separation plate

It is also possible to have heat exchangers with two different plate packs and a separation plate in between.

In this way, several arrangements can be made, e.g:

  • two fully independent heat exchangers in one shell, with independent plate side and shell side. Plate corrugation and flow directions might be different for each plate pack;
  • one medium on the shell side with the same or different medium on the plate side. Plate corrugation and flow directions might be different for each plate pack (shell side hole in separation plate);
  • same or different media on shell side and single medium on plate side. Plate corrugation and shell side flow directions might be different for each plate pack (plate side hole in separation plate).

The plate thickness of the separation plate depends on the application and the possible pressure difference between the shell chambers.