Çamaşır kurutma makinalarında otomatik temizlenen filtre tasarımı
Self cleaning filter design for dryers
Yazar: ONUR MUHİDDİN
Danışman: YRD. DOÇ. DR. İSMAİL GERDEMELİ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2013
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: Filtreler = Filters ; Kurutucular = Dryers

Özet:
Son yıllarda beyaz eşya sektöründeki gelişmeler, teknolojik alandaki gelişmelere paralel olarak ilerleme göstermektedir. Kullanıcılara kullanım kolaylığı getiren, enerji verimliliğinde üstün olan ürünler; hem üstünlük hem de prestij açısından piyasada ön plana çıkmaktadır. Bu çalışma sonucunda hedeflenen enerji verimliliğini düşürmeden kullanıcı dostu bir makina oluşturmaktır.Çamaşır kurutma makinalarında proses havasındaki lifleri tutmak için kullanılan filtre elemanının otomatik temizlenmesi istenilmektedir. Bu şekilde kullanıcıların lif ve pislikler ile teması en aza indirgenecek ve her çevrim sonunda temizlemeleri gereken bir filtre gereksinimi ortadan kalkacaktır. Bu da kullanım kolaylığı ile birlikte piyasada öne çıkmayı beraberinde getirecektir.Bu çalışmadan istenilen en az 10 çevrim boyunca kullanıcı tarafından temizlenmesi gerekmeyen bir filtre olmuştur. Ayrıca bu tasarımı yapılan filtrenin enerji verimliliğinde negatif bir etkisi olmaması istenmiştir. Bu tasarımın ekonomik boyutu da önem arz etmektedir. Bu tasarımın maliyetinin makinaya uygulanacak düzeylerde olması gerekmektedir.Çalışmaya patent ve piyasa araştırması ile başlanmıştır. Piyasada otomatik temizlenen filtre tasarımına sahip tek bir ürün bulunmaktadır. Bu ürün şu anda herkes tarafından kullanılmayan üstten yüklemeli çamaşır kurutma makinası tipidir. Şu anda kullanılan mevcut çamaşır kurutma makinası tiplerinde otomatik temizlenen filtreli bir makine bulunmamaktadır.Patent araştırmaları çok önemli olmaktadır. Yapılan patent araştırmalarında bu konu üzerine alınmış veya başvurusu yapılmış çok sayıda patent bulunmaktadır. Patent kısıtları ciddi bir şekilde irdelenmiş bizi kısıtlayabilecek yöntemler belirlenmiştir. Ayrıca bu patent araştırmasından diğer firmaların bu konu üzerinde ciddi bir şekilde çalıştıkları çıkartılabilir.Çeşitli kaynaklardan filtre ile ilgili literatürler incelenmiştir. Bu literatür incelemesi sonucunda filtre temizleme ile ilgili hangi yöntemlerin kullanılabileceği belirlenmiştir.Bu yöntemler sonucunda çalışılabilecek konular ayrılmış ve bunlar sonucunda çeşitli fikirler ve bunlar sonucunda konseptler oluşturulmuştur. Laboratuvar çalışmalarında bu konseptlerle ilgili ön çalışmalar yapılmıştır. Bu çalışmaların sonucunda hangi yöntem ile ilerleneceği seçilmiştir.Seçilen konsept ile ilgi ek bileşen gereksinimleri oluşmuştur. Bu bileşenler çeşitli literatürlerden ayrıntılı bir şekilde araştırılmıştır. Hangi tip bileşenlerin kullanılabileceği belirlenmiş ve ayrıntılı incelenmiştir.Seçilen konsept ile ilgili temizleme şekillerinden daha iyi olanını belirleyebilmek için bir test düzeneği oluşturulmuş ve testler gerçekleştirilmiştir. Testler sonucunda makinada uygulanmak üzere bir yöntem seçilmiştir. Karar verilen bu yöntem makinada prototipi yapılarak uygulanmıştır.

Abstract:
In recent years development on the white goods sector, shows improvement in parallel with technological developments in the field. The products, which are user friendly and have best energy efficiency, gains advantage and prestige against the rival products. Primary aim of this work is making a user friendly dryer without decreasing the energy efficiency.There are particles, which are come out from the laundries are called lint. Lint come from the laundries while using and washing. These particles remain at the laundries when the user places them to the dryer. These particles transfer to the process air by the high airflow generated in the dryer. Lint, which are in process air, accumulates at the important parts of the dryer and in time this accumulation causes dryer to stop working.There is a filter in the dryer for collecting that lint from the process air. This filter has a filter mesh, which collects the lint. At the end of each cycle, the user should clean the filter.Most of the lint catch by the filter but some of them pass from the filter mesh. For some products, this filter?s catch ratio is acceptable, but for others it is not. Additionally to this filter, there are two filters more for the dryers that needs more catch ratio. Thus, life of the dryer is extended.Every cycle, user should clean the lint filter. In addition, the user should clean additional filters in some dryer types after five cycles.Cleaning of the lint from the lint filter after every cycle is not a user-friendly process. When we reduce the interaction of the user with the lint, the dryers that have self-cleaning filter will be a preferable product.Aim of this work is designing a filter for catching the lint in the process air of the dryer which is cleaning by automatically. With this, user?s interaction with lint and dirt will be reduced. Also there will be no need to clean lint filter after every cycle. With all of these, the dryer will be more easy to use and in the market, it will be more preferable.What is demanding from this work is designing a filter, which is not necessary to clean it for about ten turns. Furthermore, this filter should not affect the energy efficiency negatively. This design?s economic conditions are also very important. The cost of this self-cleaning filter should not be high.First and the most important part is patent and market research. In market, there is only one product, which has self-cleaning filter. This product is a top loading dryer, which is not widely used in every country. Front loading dryer type is more common and there is not any self-cleaning filter in this type of dryer.The patent research for self-cleaning filter design is very critical for us. In patent research lots of patents and patent applications are seen for self-cleaning filter design. Each of the patents that can limit us were examined carefully. With this examination the methods, which could limit us defined. Also with this patent research, we can easily say that other companies are working for this topic seriously.Literatures about filters were examined from different sources. Filters are in use of different fields in market. The filters that could be suitable for dryers examined. For conclusion of this research, the dryer?s present filter is better for self-cleaning and decided to work for this type of filter.As a result of this literature and patent research for dryer filter three methods selected. These methods are; cleaning with counter airflow, water assisted cleaning and cleaning with mechanical action.With these methods the subjects, which can be studied selected. These selected subjects, ideas and concepts were generated. In laboratory preliminary works about these concepts were done. As a result of these preliminary works, which method will be used was chosen.To apply chosen concept to dryer, necessary components were selected. In this chosen concept, these components are pump and nozzles. For the chosen concept, necessary nozzles for cleaning were searched with the help of nozzle catalogues. Places where the nozzles can place inside the machine selected. Nozzle dimensions were chosen according to these places.Nozzles have a certain flow rate and pressure to work. Nozzles work optimal at that flow rate and pressure value. Flow rate and pressure affects the velocity of the water, which exit the nozzles. With high pressure and flow rates, we gain high water velocity values from nozzle exit and with high velocity values, high impacts to the filter are obtained.Pressure and flow rate value is critical for the water angel, which exit the nozzle. Below the specific pressure values, nozzles cannot give the desired water exit angle. Pressure and flow rate values are also important for uniform spray, which is very important for full cone nozzles. With low-pressure and flow rate values, full cone nozzles cannot spray uniformly, weak at the center strong at the edges. This spray pattern has negative effect for the filter cleaning. Uniform spray pattern gives us the best filter cleaning and this uniform spray can be obtained by pressure and flow rate. For these flow rates and the pressure values are very important for the pump selection. The pump should meet flow rates and pressure values for nozzles.Condensed water will be used for the spray. Thus, water volume for the spray is limited in the dryer. This volume limits flow rate values and flow rate values limit the selection of powerful pumps.Pump dimensions are also important. Pumps will be placed in dryer and in dryer, there are not much places to put big components. Smaller pumps will be better for positioning. While searching pumps, these criteria have been considered. Pumps have been searched from the catalogues. Pumps, which can be suitable for us were chosen from these catalogues by the criteria explained above.For filter cleaning, which types of nozzles are effective and which places to locate should be determined. For determine the nozzles and places a test setup is prepared. Filter and a nozzle facing this filter can be mounted in this setup. In this setup, a nozzle installation facing the filter is present. This nozzle installation can be placed at various positions and angels. When designing the setup it is considered that, the dimensions should be smaller. With that setup wide range of positions and angels were tested.The tests that have done on the setup are split up to two as spray to filters inner surface and outer surface. These tests are also split up according to nozzle types. Angled tests have been specified according to nozzle types. At cleaning tests, the results analyzed and with the help of these results, one of the efficient cleaning methods has been chosen.A prototype set for test according to chosen method in dryer. The prototype set like one plane lint filter. Thus, the number of these nozzles can be reduced. In our current filter, there are four surfaces. Each surface should be cleaned every cycle. If we want to use our current filter we should use four nozzles. With four nozzles, we need pump that have more powerful and bigger. When we use one plane filter the nozzle number decreases to two. With these numbers pump that chosen for tests can be usable.For the use of one plane lint filter, there should be a flat plane behind the filter. That plain does not exist on the filter current location. For that, the prototype set like two parts. One part is lint filter and the other one is a plane that filter sits.One plane filter should be removable. Thus, the drain hole and gasket groove designed in filter pad.The nozzle holes are in filter pad. Nozzles were placed to these holes and fixed. These nozzles are making effective cleaning at specific distance and specific angles. These distances and angles specified at tests. With the help of these tests for prototype, the distance and angle of the nozzles were adjusted.In filter pad, there is another groove which water full of lint flows. This groove has an angle relative to the ground. Thus, the water full of flint flows from this groove and exits the filter from the drain hole.With removable filter we can know the filling and cleaning level. In addition, the condenser that locates under the filter location should be removable and this limits our filter height.The tests were done in a condenser dryer. The filter pad fixed to the front seating with screws. For placing the nozzles in front seating and front wall the holes were opened. The nozzles were placed to these holes. Backside of the machine another hole was opened for the evacuation of the condense water. Condense water which condenses in condenser accumulates in pump housing. When the water level reaches at specific level, pump works. With this hole pump never works and the water accumulates in a tank which is outside of the machine. So the water level and the lint in condense water can be seen.The dirty water also taken in a tank that is outside of the machine. With this amount of the lint, which comes from the cleaning water, can be seen. Some of the lint can pass to the condense water. But amount of the passing lint is not very high and not very important.In tests, there were two cleaning phases. First cleaning is in the middle of the cycle and the second one is at the end of the cycle. After every cycle the accumulation of lint in filter were observed. The auto clean filter and the normal filter compared after every cycle. Accumulation of the lint in auto clean filter occurs slowly. The auto clean filter can work smoothly for about ten cycles. Without auto clean filter, dryer can work 4 cycyle smoothly.