Anti-splash urinals

Abstract

A urinal uses a sloped interior back wall to create a specific angle between an incoming urine stream and the back wall to effect an anti-splash phenomenon which involves the contact angle hysteresis and the coanda effect, thereby at least to minimize urine splashing. The contact angle hysteresis deals with the perpendicular angles at which the urine stream comes into contact with the back wall of the urinal bowl, that is the amount of angle degrees between the angle of surface of the bowl and the angle of the urine stream at the point of contact. This angle takes advantage of the Coanda effect so as to cause the fluid (urine) to run down the surface of the back wall to the bottom of the urinal, rather than splashing back. The Coanda effect is the tendency of a fluid jet to stay attached to an adjacent curved surface that is very well shaped. In one embodiment, the interior back wall is vertically sloped towards the user, at an angle greater than 20° from the vertical (e.g., 30° to accommodate a 60° urine stream), and the back wall may be further curved from side to side. In an other embodiment, the interior back wall has a undulated top-to-bottom or vertical contour.

1 . An anti-splash urinal utilizing the Coanda effect comprising a bowl for reception of urine and disposition thereof to a drain, and a back wall angled from the vertical sufficient to permit a stream of the urine to stay attached to and flow along said back wall without undue splashing therefrom. 
   
   
       2 . An anti-splash urinal according to  claim 1  in which said back wall is curved from side to side from the vertical. 
   
   
       3 . An anti-splash urinal according to  claim 1  in which said back wall is undulated from its top to bottom. 
   
   
       4 . An anti-splash urinal comprising a bowl for reception of urine and disposition thereof to a drain, a back surface angled from the vertical sufficient to permit a stream of the urine to frictionally stay attached to said back wall and to flow therealong in accordance with a skin frictional effect occurring between the urine stream and said surface, thus tending to slow the moving urine, to create a resistance to the flow of the urine, to pull the urine towards said surface and to cause it to stick to said surface. 
   
   
       5 . An anti-splash urinal according to  claim 4  in which said surface has a curvature with respect to the urine stream is insufficiently sharp as to inhibit splashing of the urine from said surface. 
   
   
       6 . An anti-splash urinal according to  claim 4  in which said surface has an angle made with the urine stream that is insufficiently sharp as to inhibit splashing of the urine from said surface. 
   
   
       7 . An anti-splash urinal according to  claim 6  wherein the angle is greater than 20° from the vertical to accommodate a 60° urine stream. 
   
   
       8 . An anti-splash urinal according to  claim 6  wherein the angle is at least 30° from the vertical to accommodate a 60° urine stream. 
   
   
       9 . A method for avoiding splashing in a vertically oriented urinal having a back wall surface in a bowl for reception of urine and disposition thereof to a drain comprising the steps of angling the back surface from the vertical orientation sufficient to permit a stream of the urine to frictionally stay attached to the back wall surface and to flow therealong in accordance with a skin frictional effect occurring between the urine stream and the surface, thus tending to slow the moving urine, to create a resistance to the flow of the urine, to pull the urine towards the surface and to cause it to stick to the surface. 
   
   
       10 . A method according to  claim 9  further including the step of curving the surface with respect to the urine stream so as to be insufficiently sharp as to inhibit splashing of the urine from the surface. 
   
   
       11 . A method according to  claim 9  further including the step of angling the surface with respect to the urine stream so as to be insufficiently sharp as to inhibit splashing of the urine from said surface. 
   
   
       12 . A method according to  claim 11  wherein said angling step comprises the step of incorporating an angle to the surface which is greater than 20° from the vertical to accommodate a 60° urine stream. 
   
   
       13 . A method according to  claim 12  wherein the angle is at least 30° from the vertical to accommodate a 60° urine stream.