a fig4 in the implementation shown in fig3 a and fig4 the plate assembly 15 a incorporates the plate 15 the plunger assembly 22 and the spring 19 the plate assembly 15 a is assembled by inserting the inner plug 18 into the opening 16 of the plate 15 see for example fig2 b and fig4 then the spring 19 is dropped onto the plate 15 the outer plug 17 is slid onto the inner plug 18 until a set of locking features 18 a fig5 engages with the outer plug 17 in an alternative arrangement a sealing and drainage device 231 includes a locking feature such as a pin 111 to lock the outer plug 17 and the inner plug 18 together as shown in fig6 the sealing and drainage device 131 shown in fig3 a contains the ball 14 trapped within the bore 12 and the plate assembly 15 a the ball 14 is held inside the bore 12 by a spring 20 above the plunger assembly 22 the plate assembly 15 a may be attached to the housing 11 by staking or press fitting the plate assembly 15 a into the housing 11 alternatively the plate assembly 15 a may be threaded into the housing 11 to allow removal of the plate assembly 15 a so that the ball 14 and the plunger assembly 22 can be serviced in the assembled condition the spring 19 pushes the plunger assembly 22 up such that the outer flange.