Heat exchanger series is the most advanced design of polyblock Heat Exchangers. These are constructed from identically formed impervious graphite blocks with two types of passages viz short radial passages of 100 to 150mm length converging into a central cavity and short length axial passages with remixing of all the axial tube fluids in a mixing cum redistribution channel every 150 to 300 mm travel of the axial fluid. This particular feature of hydraulic design gives abundant turbulence even at low flow rates and enhances the ‘U’ and reduces the fouling & scaling drastically. The effect of high ‘U’ and lower fouling coefficient ‘s’ is that for the same heat duty the HTA value is lower. Due to their main features of robustness, high mechanical strength and exceptionally long working life, these heat exchangers are widely used in Pharmaceutical Industries, pesticide and fumigant sectors, Dye Stuffs, other Chemical Process Industries, petrochemicals, Phosphate Fertilisers and Pickling lines of Steel Rolling Mills etc.
- Heat exchange between two corrosive liquids
- Condensation of corrosive organic & inorganic vapors
- De-superheating of vapors, Partial Condensation & sub-cooling
- The heat exchanger assembly is made from a stack of cylindrical impervious graphite blocks, depending upon the HTA requirement and the desirable fluid flow rates.
- The stack of blocks is fitted with headers at both the ends.The graphite blocks and headers are housed in an MS shell for service fluid passage and also to impart protection and mechanical strength to the assembly.
- To separate the blocks and isolate the flows, teflon gaskets are used between each blocks.
- The stack of blocks is held tightly under compressive load using disc or spring washers on long pin bolts and nuts assembly. Deflector plates are used on entry nozzles to avoid direct impingement.
- Process Fluid flows through the main axial passage of the graphite header and gets distributed into multiple axial passages and enters middle block
- Then it passes through short axial passages and reaches the mixing cum redistribution channel before entering the next block
- The same pattern is followed afterwards till the process fluid is collected by the lower header
- Service fluid flows through the radial passages of the 1st block to the central passage and then passes through the central passage to the second block
- Then in the second block it passes from central passage to the radial passage and gets remixed with all the radial passages in the outer radial recess between the graphite block and the cylindrical holder
- From this outer common channel it gets redistributed into the radial passages of the next block
- The same pattern is followed afterwards till the Service fluid is collected by the exit nozzle of the bottom holder The process fluid and service fluid are kept apart by teflon gaskets at the interface of each block with the next block