This invention relates to a device that will automatically and without requirement for additional power, remove fluids from pipes used to convey gaseous substances under pressure or vacuum conditions without exposing the gas to atmosphere.

Some industries convey gases laden with moisture, this moisture can present problems with the subsequent processing of the gases. Such a situation exists in the mining industry (coal) where there is currently no effective, automatic, self-powered method of removing condensed liquids from the gas system.

According to this invention there is provided an automatic fluid trap and draining unit comprising a gas-tight tank, a linked inlet and outlet valve arrangement, a bleed valve to assist emptying by equalising pressures,a float operating on an outer hollow shaft with spring toggle mechanism to accelerate movement, an outer hollow shaft operating on an inner spindle with spring toggle mechanism to maintain closing pressure on the valves during fill and empty cycles, automatic valve opening/closing when the tank is filled or drain to a specific level, powered only by the entry and exit of fluid, two (2) concentric shafts comprising an inner spindle and an outer hollow shaft, and a filter on the inlet to prevent the ingress of large and damaging pieces of debris.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing; Entry of the fluid, by gravity, is permitted at the start of a typical cycle by an open inlet valve 1 , the linked outlet valve 2 isclosed at this time. As the fluid level 14 rises in the tank 4 , the float 5 rises and comes into contact with an upper collar 7 on the outer hollow shaft 6 as the fluid level rises further the float now raises the outer hollow shaft and the primary toggle mechanism 9 begins to operate, at this time the opposing springs on the toggle are being compressed. When the float has raised the outer hollow shaft sufficiently the springs of the primary toggle mechanism pass the point where they are aligned and the

spring force now causes the toggle mechanism to raise the outer hollow shaft independently of the effort from the float. The spring force is such that the outer hollow shaft rises very quickly and impacts on— an upper collar 11 on the inner spindle 10. The force of this impact is such that the secondary toggle mechanism 13 on the spindle is overcome and the inlet valve is closed and at the same time the linked outlet valve is opened, also at the same time the bleed valve 3 is opened. Opening the bleed valve equalises the pressure inside and outside the tank to assist draining of the fluid. The secondary toggle mechanism now holds the inlet closed and outlet open whilst the fluid is allowed to drain from the tank, as the fluid level falls so does the float and it contacts a lower collar 8 on the outer hollow shaft, the weight of the float is such that it makes the outer hollow shaft fall. When the outer hollow shaft has fallen sufficiently the springs of the primary toggle mechanism pass the point where they are aligned and the spring force now causes the toggle mechanism to lower the outer hollow shaft independent of the weight of the float. The spring force is such that the outer hollow shaft falls very quickly and impacts against a lower collar 12 on the inner spindle. The force of this impact is such that the secondary toggle mechanism on the inner spindle is overcome and the outlet valve is closed and at the same time the linked inlet valve is opened, also at the same time the bleed valve is closed.

The cycle is now repeated indefinitely, as fluid can now enter the unit again.

The spring toggle mechanisms are similar in design and comprise a spindle linking the shaft to a trunnion, the trunnion is carried in a bracket that is in a fixed position within the tank. The spring acts between the shaft and the trunnion to give a toggle effect. Two of these assemblies are mounted diametrically opposite each other to balance the forces and obtain the desired type of motion- The fluid enters the unit via a filter arrangement 15 in -the inlet pipe, which prevents the ingress of harmful debris. All moving parts are within the walls of the tank, refer to drawing. The inner spindle is located by an upper guide 16 and a lower guide 17.