Patent Publication Number: US-2005132675-A1

Title: Device for filtering of the air flow in pneumatic systems

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an innovative filter device for compressed-air pneumatic systems.  
      2. State of the Prior Art  
      It is known that in compressed-air pneumatic systems, it is required that the solid particles be filtered off from the air and the water condensate be separated from the flow before admission of air into the distributors and actuators. For this reason, a filter device is usually provided which is equipped with a replaceable filtering cartridge and with means for separation of the condensate, and automatic or manual means for the condensate discharge.  
      In known devices the servicing interventions, such as replacement of the filter cartridge, are difficult and often uncomfortable, above all when the unit is positioned in regions of uneasy access to the machine using it. In particular, for the condensate collection at the filter base, the cartridge is always vertically disposed in a cup under the air inlet, the air flow being radially directed from the outside to the inside of the cartridge itself. Such an arrangement creates problems in terms of vertical bulkiness that can he hardly resolved and uncomfortable operations are required even for unscrewing the filter cup.  
      In addition, also unresolved are some operational problems impairing the arrangement reliability. For example, the automatic condensate discharge arrangements are subjected to jamming in the presence of solid particles suspended in the air and are therefore often refused by a user.  
      It is a general aim of the present invention to obviate the above mentioned drawbacks by providing an efficient filter device, of easy placement, reduced bulkiness and easy accessibility above all for servicing operations and replacement of the cartridge and that, if equipped with an automatic condensate discharge device, is not subjected to jamming due to the presence of solid particles entrained into the device by the air flow.  
     SUMMARY OF THE INVENTION  
      In view of the above aim therefore, in accordance with the invention, a filter device for compressed air systems has been devised which comprises a body provided with an inlet for the air to be filtered and an outlet for the filtered air, a filter unit with a filtering cartridge and a condensate collection and discharge assembly being disposed between the inlet and outlet, characterized in that the filter unit is extended along a horizontal axis and the condensate assembly is disposed under the filter unit and downstream thereof.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      For better explaining the innovative principles of the present invention and the advantages it offers over the known art, a possible embodiment applying said principles will be described hereinafter, with the aid of the accompanying drawing in which the only figure shows a possible embodiment of the invention, given by way of example only. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      With reference to the figure, a filter device made in accordance with the invention and generally denoted at  110  is shown in sectioned elevation side view. The device comprises a body  111  provided with an inlet  112  for the air to be filtered and an outlet  113  for the filtered air. Housed in the body  111  is a filter unit  114  and a condensate collection and discharge assembly  115 .  
      In accordance with the principles of the invention, the filter unit  114  is extended along a horizontal axis  116  while the condensate assembly  115  is disposed under the filter unit and is extended along a vertical axis  117 . The condensate assembly is placed downstream of the filter unit and the air flow radially passes through the filter from the inside to the outside.  
      In particular, the filter unit is provided with a suitable cylindrical filtering cartridge  118  received in a suitable seat  119  sealed by a screw threaded plug  120  of a horizontal axis  116  as well.  
      Advantageously, the air inlet  112  communicates with the cartridge inside  118  through an on-off valve  121  having a closure member  122  pushed to the closed position against an abutment  123  upon the thrust action of a spring  124 . Axially present internally of the plug  120  is a rod  125  that, when the plug  120  is correctly screwed in place, keeps the valve open against the thrust action of spring  124 .  
      The condensate assembly  115  comprises a cup  126  for collection of the condensate entrained through the filter. The cup has a lower exhaust outlet  127  that can be operated either manually (by means of a screw threaded plug or valve, for example) or, advantageously, in an automatic manner by a known float valve  128  that opens when the liquid level in the cup overcomes a pre-established threshold.  
      Present on the cup  126  top is a system consisting of inclined lamellae  129  such disposed that they are licked by the air flow directed towards the outlet  113  so as to separate the condensate from the flow itself and cause dripping of the condensate into the underlying cup.  
      At this point it is apparent that the intended purposes have been achieved. The horizontal arrangement of the filter, with front extraction, makes the device compact and easily placeable as well as of easy and quick servicing. In addition, the air flow passing through the filter cartridge from the inside to the outside makes the intercepted dirt remain within the cartridge when it is removed from its seat, thereby facilitating the cartridge replacement and making it quicker. The condensate separation after filtering also prevents the dirt particles from reaching the condensate assembly causing blocking or clogging of the discharge outlet. This ensures a high reliability of a possible advantageous self-discharge device.  
      The automatic closure of the incoming air flow when the filter plug is unscrewed avoids accidental air escape into the surrounding atmosphere and makes the filter replacement quicker and more comfortable. Since separated flow cut-off cocks are not required, the device is cheaper and less bulky.  
      Obviously, the above description of an embodiment applying the innovative principles of the present invention is given by way of example only and therefore must not be considered as a limitation of the scope of the patent rights herein claimed. The conformation and exact proportions and sizes of the different parts can vary depending on the specific practical requirements. The air inlet and outlet connectors can be manufactured in compliance with any desired known structure.