IE49531B1 - Slurry tanker - Google Patents

Abstract

A slurry tanker of the vacuum type comprises a tank 2 for storing slurry, an air pump 3 for evacuating air from the tank so as to suck slurry into the tank and for pressurizing the tank to discharge slurry from it, a trap 1 connected in an air line between the tank and pump so as to collect slurry from the air line as air is evacuated from the tank by the pump, and a pressure responsive valve 10 connected in an outlet from the trap so as to open automatically and vent material from the trap each and every time the tank is pressurized by the air pump. The valve outlet is preferably located in the bottom of the trap so that it is emptied when the valve is opened. The valve is preferably a spring-loaded valve provided externally of the tank and trap so that it can be easily cleaned. Preferably, the valve comprises a spring-loaded valve member supported in a slurry shield pivotable over the open end of the outlet duct.

Description

This invention relates to a slurry tanker of the vacuum type in which an air pump sucks slurry into a tank by evacuating air from it, and subsequently discharges the slurry by pressurizing the tank.

In known slurry tankers of the, vacuum type, the air pump communicates with the tank through an opening in the top of the tank and is protected against the ingress of slurry by devices such as valves and traps. For example, a float valve is provided to close said opening when the tank is full, and a trap is provided in the air line to the pump so as to collect any foam or other material that may be sucked through said opening before the tank is full and the float valve closes. A window or sight glass is provided tqindicate the level of material in the trap, and a manually operated valve is provided to allow the operator to empty the trap when necessary. Such an arrangement is satisfactory in protecting the pump provided the operator remembers to empty the trap before it becomes full, but it has be.en known for the operator to fail to do this. The present invention therefore aims to provide means to protect the pump without requiring the attention and supervision of the operator.

This object is achieved according to the present invention by providing a slurry tanker of the vacuum type having a trap in the air line between the tank and the pump 9 5 31 with a pressure responsive valve connected in an outlet from the trap so that the valve opens automatically to vent material from the trap each and every time the tanker is pressurized. The valve therefore ensures that the trap is cleaned every time the tanker discharges slurry so that it never collects sufficient material to be sucked into the pump.

Furthermore, it will be appreciated that the valve acts as a pressure relief valve so that it is unnecessary to provide a separate pressure relief valve, such as is provided in known slurry tankers.

The air vented by the valve ensures that it is cleaned every time it operates, thereby ensuring that it is not blocked or jammed and continues to operate correctly.

Preferably, the valve controlled outlet from the trap is located in the bottom of the trap so that it is emptied each time the valve operates.

The valve itself is preferably of a simple, rugged design, and may be, for example, a spring-loaded valve.

The accompanying schematic drawing (Figure 1) illustrates a slurry tanker, basically of known construction, but which has been modified to incorporate the invention. The trap 1 is located within the tank 2 at its front end, and is connected between the air pump 3 on the trailer towing arm and an opening at the top of the tank that is controlled by a float valve 4. In use, the pump is driven by the power 4-9 5 3 J take off shaft 5 of a towing tractor and, under the control of a manual control valve 6, either evacuates air from the tank to suck slurry into the tank through a valve-controlled spout 7 at the rear, or pressurizes the tank to discharge slurry through said spout. A spreading attachment 8 may be connected to the spout to spread the slurry in a jet or spray over the ground behind the tanker. A spring loaded safety valve 9 at the top of the tank protects it against an excessive build-up of pressure therein.

In the known tanker, a pressure relief valve and a manually-operated control valve are located in the front end wall of the tanker in communication with the trap, the relief valve being located towards the top of the trap and the manually-operated valve towards the bottom to empty the trap. However, this arrangement is modified according to the invention by replacing both valves with a. single, spring-loaded, pressure responsive valve 10 connected in an outlet from the bottom of the trap so as to open and vent waste material and air from the trap when the tanker is pressurized. Typically, the valve opens at a pressure of p.s.i. An example of a suitable valve is illustrated in Figures 2 and 3 of the accompanying drawings.

The illustrated valve comprises an outlet pipe 11 that is connected via an elbow to the trap 1. A channel section housing 12 is pivotally connected to the pipe 11 via lugs 13 and pivot pins 14 and supports a spring-loaded valve assembly 15 that is adapted to co-operate with the open end of the pipe 11. The valve assembly 15 comprises a plunger 16 5 that is slidably mounted in holes in a pair of guide plates 17 connected between the side walls of the housing 12, and a compression spring 18 that cuts between one of the guide plates 17 and a valve member 19 on the adjacent free end of the plunger 16 so as to urge the valve member 19 towards the 10 pipe 11 and produce sealing engagement between the washer 20 and the open end of the pipe. The plunger 16 can be retracted by a handle 21 against the action of the spring, and the housing pivoted aside to expose the open end of the pipe for cleaning of the valve. The housing 12 also serves as a shield to limit the spread of slurry ejected through the valve.

Claims (9)

1. What we claim is :1. Λ slurry tanker of the vacuum type comprising a tank fur storing slurry, an air pump-for evacuating air from the tank so as to suck slurry into the tank and for pressurizing 5 the tank to discharge slurry from it, a trap connected in an air line between the tank and pump so as to collect slurry from the air line as air is evacuated from the tank by the pump, and a pressure responsive valve connected in an outlet from the trap so as to open automatically and vent 10 material from the trap each and every time the tank is pressurized by the air pump.

2. A slurry tanker as claimed in claim 1 in which the valve outlet from the trap is located in the bottom of the trap

3. A slurry tanker as claimed in either of the preceding 15 claims in which the valve is a spring-loaded valve.

4. A slurry tinker as claimed in claim 3 in which the valve is located externally of the tank and trap and comprises a valve member that is spring loaded against an outlet opening from the trap so as to close said opening, the spring 20 leading of the valve member determining the pressure response setting of the valve.

5. A slurry tanker as claimed in claim 4 in which the valve member is movably mounted in a support assembly so that it acts axially against the open end of an outlet duct from 25 the trap so as to close said open end.

6. A slurry tanker as claimed in claim 5 in which the support assembly is moveable relative to the outlet duct to move the valve member out of axial alignment with the outlet duct, thereby exposing the open end of the latter 5 for cleaning.

7. A slurry tanker as claimed in claim 6 in which the support assembly is pivotally mounted on the outlet duct so as to swing the valve member out of axial alignment with the outlet duct once the valve muncer is disengaged axially

8. 10 from the open end of the outlet duct. B. A slurry tanker as claimed in any one of claims 5 to 7 in which the support assembly is adapted to act as a shield that limits the spread of slurry vented from the valve.

9. 15 9. A slurry tanker of the vacuum type substantially as herein described with reference to the accompanying drawings. Dated this 29th day of February 1980.