Hisaka Plate Heat Exchanger Spares
Plate Heat Exchanger Mechanism
Construction The heat transfer plate, is manufactured by press forming thin sheets of corrosionresistant metals such as stainless steel and titanium. A plate element consists of this heat transfer plate with its peripheral area sealed with a synthetic rubber gasket. In the plate heat exchanger, the required number of plate elements are suspended on a guide bar, and sandwiched between fixed steel frame and movable steel frame and tightened together with bolts/ nuts. There are over 40 types of plate elements, and each are precisely designed so that they work maximum performance in each process. The heat transfer plate and gasket are high precision formed products, and tightened with uniform force in order to achieve high sealing performance.
Tightening lengths
The dimension between the fixed and movable frame is called the tightening dimension, and the unit is tightened between the maximum dimension and the minimum dimension. The tightening lengths is shown on the assembly drawings and on the nameplate of the unit.
Manufacturing number
When contacting us in regards to maintenance, please notify us of the manufacturing number. It is possible to understand all specification of the unit, just with the manufacturing number. The manufacturing number is shown on the drawings and on the nameplate on the unit.
Maintenance for Equipment
There are no moving parts on a plate heat exchanger, making it a device with a low number of component parts, and relatively free of malfunctions or other trouble. However, with extended periods of operation, there may be deterioration of gaskets, scaling by water residue and other debris, and corrosion and cracking may occur. If left as is, this will lead to a reduction in performance, intermixing of fluids and leakages, and can ultimately lead to stopping of the unit and the entire plant. In order to prevent this, it is necessary to periodically disassemble the unit, and perform inspection and cleaning.
Main reasons for reduction in performance and leakages of the plate heat exchanger, include the scaling by water inside the heat exchanger and deterioration of the gasket due to extended use. For the problem with scaling by water residue, we recommend that decreasing the performance be monitored, and to perform periodic opening and cleaning accordingly.
Maintenance
Spare parts The reliability of the gaskets has been proven through years of research, experience, evaluation and actual performance at HISAKA. Though a plate gasket seems simple, there are many technical ideas in the shape, thickness, width, material, and are nothing like the ordinary piping flange gaskets punched out from a rubber sheet material. The selection of the synthetic rubber compound that is provided as the product, is closely evaluated for its cost, chemical resistance, heat resistance, and anti cracking performance. From several thousand compounds, we select those that clear these evaluation factors at the highest level. In addition, they are repeatedly checked in various endurance tests before the final decision, and are vulcanized and mold formed in precision dies that take into account amount of shrinkage for the final dimensions. The gaskets are the only consumable part in the maintenance of plate heat exchangers. A lot number is shown on the gasket, making it possible to identify the date of manufacture, the die used, and material. For the material, color marking is utilized to make it easy to identify visually.
The heat transfer plate is formed in the press facilities of HISAKA which have the largest 40,000 ton press machine in the world and other unique press machine. In order to press the plates under optimal conditions, the plate die is checked every few thousand to 10 thousand shots. The plates in the plate heat exchanger are thin and of 0.5mm to 1.0mm in thickness. In order to press these thin plates without press defects such as flaw, necking, the high pressing tools design and manufacturing technology, and pressing technology of HISAKA are absolutely essential. These plates are printed with a lot number using an electronic marker as well as gaskets, and the plate thickness, material, and manufacturing date can be found, and makes it possible to track down the mill certificate plate material by mill certificate.
The frame plate is a pressure retaining part that maintains the sealing of the unit by tightening together the plates with uniform tightening force. Because of this, if there is corrosion or deformation, it will require periodic overhaul. There is also a model with rubber lined (NJ/NP type) on the connection holes of the frame plate to prevent the carbon steel material from corrosion by fluid. This rubber lined is called a rubber boot, and requires replacement if deterioration is found.
Tightening bolts and nuts will also begin to rust depending on the circumstance of the unit, so we recommend that periodic greasing be performed for rust prevention. Also, a bolt cover to protect the bolts, is available as an option.
The plates and gaskets of the plate heat exchanger can be supplied, and tightening bolts, nuts, rubber boots, and adhesive glues can be also supplied for maintenance.
Cleaning methods Remove the gasket from the plates, and clean with a deck brush, or water jet. In a case of water jet, to avoid deformation of the plate and damage to sealing surfaces, set on a flat panel and a reinforcement panel, and the water jet should be from a distance of 200mm or more
Soaking…The plates are soaked in a chemical bath. In this case, it is necessary to control the process, being very careful of the chemical temperature, concentration and washing time so that the plates are not corroded by the chemicals.
Cleaning-in-place (CIP)…After washing through the heat exchanger by hot water with a higher flow rate than designed, a chemical (acid, alkali) is circulated for chemical cleaning. After chemical cleaning, rinse thoroughly with fresh water not to remain a chemical residue
Introduction of Maintenance Services
The "Full Service Package" is a service that is provided as a full course menu for maintenance of the plate heat exchanger. The plate heat exchanger in the plant is returned us as is, and we perform all maintenance work including disassembly, inspection, cleaning, regasketing assembly, and inspection. When completed, the unit is returned to the customer.
Plate cleaning…The plate cleaning work, which is the main part of the "Full Service Package", is provided as a stand-alone service.
Maintenance service on site…A service engineer visits to support maintenance work on site.
Fault Detection
Scaling
There are a lot of applications for plate heat exchangers, and various types of scaling will be occurred on the plate surfaces. Here, the scaling by industrial water and scaling seawater are explained.
Fault Detection
Seawater strainer Objectives…Foreign objects such as seaweeds, shellfish, wood chip/fiber, etc. in seawater are removed so that they do not enter the plate heat exchanger, and prevents the clogging of the inlet port hole. Operation principles…By switching the flow direction inside the filter (strainer) element, foreign objects are discharged from the backflushing valve. Feature…(1) Backflusing is automatically performed with a pressure differential gauge and timer setting. (2) The amount of water in the backflushing is 10% of normal flow, and cleaning is possible during operation. (3) Because a cylindrical punched metal is used, the straining area is large. (4) Maintenance of the punching metal part can be performed without disconnecting the main piping.
Faults detection
Marine growth When using seawater as the cooling fluid, slime, wood chip/fiber, seaweeds and other ocean life can clog to the port holes and accumurate on the heat transfer plates, decreasing seawater flow rate and heat transfer performance. Because of this, many plants periodically perform disassembly cleaning (generally once a year), but this is time consuming and costly. Therefore, as an anti-fouling system, HISAKA recommends using a combination with "Hot water circulation" system in which hot water is circulated for a certain amount of time, and "Air bubbling" in which compressed air is blown through the heat exchanger.
To Extend the Lifetime of Your Heat Exchanger
The ease of maintenance is one of the major benefits of the plate heat exchanger. It is possible to open the unit by just removing the tightening bolts, and the plates can be inspected visually. However, finding small corrosions and pinholes, and thoroughly cleaning tough scaling without damaging the thin plates require experienced skill. As a technical supporter providing "relief" and "reliability" in maintenance service, we will work to help extend the life of the plate heat exchanger as long as possible. Please utilize our services for your maintenance.
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