What’s Inside A Filter Drier – How it works hvac

Hey there guys Paul here from the engineering mindset .com in this video we’re going to be looking inside one of these the hermetic filter a dryer by Danfoss coming up what are they used for where do we find them and then we’ll cut one open and look at all the parts inside and discuss the purpose of each bit if by the end of this video you still haven’t had your fill of filter dryers then I suggest you head over to DanFoss learning and dive into their collection of free elessons danFoss is passionate about sharing knowledge so in addition to sponsoring this video they’ve also made hundreds of elessons available for free on their website including multiple courses on filters dryers you can find all of it by following the link in the video description down below where do we find these filter dryers this is a very typical model filter dryer and we’ll find these installed in the liquid line of the refrigeration system between the condenser and the expansion valve we’ve covered how expansion valves heat exchanges and refrigerants work in our previous videos do check those out links in the video description down below on the side of the filter dryer you’ll find an arrow this indicates the direction of refrigerant flow some models for heat pumps might be bi-directional and the arrow will point both left and right but in this case we have a single direction one-way filter dryer on the outside we have a powder painted surface which just prevents corrosion and the black gloss finish which just gives a premium look and feel the casing is made from steel to give it a strong structure as this will be under some high internal pressure out once connected into the refrigeration system at each end we have some solder connections which can either be pure copper or copper plated depending on the model so what do we use a filter dryer for well these are found in refrigeration systems and as you might guess from their name their job is to filter and dry the refrigerant they protect the refrigeration system and its components by capturing and absorbing water particles as well as harmful solid substances this will prevent them from cycling around the system and getting into the compressors that valves the sensors etc to keep the system running in optimal conditions anyway enough about that let’s cut it open and look inside of the components I’m just going to use a slit disk in the angle grinder to cut this one open I’m going to start with a fresh disc just to get the maximum cutting depth then I’ll lock the filter dryer into the bench vise to stop it moving around then we can just slice for it nice and easy with the grinder as I said the casing is made of steel so we’re going to get a lot of sparks flying around the workshop so we have to make sure we’re wearing some protective clothing and also move any flammable materials out of the way I’ve just reposition this in the vise to get my second cut not roughly ninety degrees to the first just let us look inside all right that’s the casing cut open let’s pull it apart to look inside so as we remove the casing we instantly see some of the key components inside the biggest component being the solid core but we’ll look at that in just a moment now at the refrigerant inlet end we have a large spring I’ve actually cut through this one so it has lost its shape and I can just pull the remaining parts of that out but the spring pushes against both the casing and the solid core this is just there to keep the core in a fixed position inside the casing next we have the core or the molecular sieve this particular model has a solid core 80% of which is a molecular sieve and 20% is an activated alumina I’ll show you some close-ups here of that porous material the solid core molecular structure acts as a filter to capture any large particles the material is similar to a sponge in that it can soak up and retain water the aluminium oxide is added in there to capture and retain the acids not all filter dryers will have activated alumina inside them it depends on the application so the refrigerant enters and surrounds the outside of the core the pressure of the system forces the refrigerant to pass through the porous material notice this groove inside the refrigerant will pass through the solid core and then collect in this groove to continue its flow towards the expansion valve at the end of the solid core we have a screen this polyester mat retains the smaller dirt particles which might have been able to pass through the solid core the material is able to capture dirt particles down to 25 microns with minimal pressure drop after the screen we have a perforated plate this is just there to keep all the internal parts in position the holes just allow the refrigerant to flow to the outlet the refrigerant then leaves the filter dryer and heads to the expansion valve so the refrigerant enters through the inlet it passes across the spring and then surrounds the outside of the solid core the spring is pushing and holding everything in place the refrigerant then passes through the solid core and as it does so the dirt moisture and acids are absorbed the refrigerant then collects in the groove at the center of the core and then it passes through the screen it then passes through the perforated plate and exits the unit having been filtered and dried the refrigerant then continues to the expansion valve ready to continue your education on filter dryers then head over to the Danfoss learning web page now and start your first course for free just follow the link in the video description below ok that’s it but if you want to continue your learning then just click on one of the videos on screen now and I’ll catch you there for the next lesson don’t forget to follow us on Facebook Twitter Instagram and of course the engineering mindset comm