GB2157268A

GB2157268A - Apparatus for delivering material via delivery tube

Info

Publication number: GB2157268A
Application number: GB08409139A
Authority: GB
Inventors: Henry John Crosby Caswell
Original assignee: KENNING MOTOR GROUP PLC
Current assignee: KENNING MOTOR GROUP PLC
Priority date: 1984-04-09
Filing date: 1984-04-09
Publication date: 1985-10-23
Also published as: GB8409139D0; GB2157268B

Abstract

Apparatus for delivering a metered quantity of liquid fuel, e.g. fitted to a tanker vehicle, is provided with means to empty the delivery tube at the end of the delivery phase, any liquid fuel remaining in the delivery tube being displaced by gas under pressure, the supply of gas being automatically discontinued when the tube vents to atmosphere. This ensures that all the metered quantity is delivered.

Description

SPECIFICATION Apparatus for delivering material via delivery tube This invention relates to apparatus for delivering a quantity of fluent material via a delivery tube. The apparatus includes means to displace any material remaining in the tube following a delivery phase. A preferred embodiment of the invention may be fitted, for example, to a road tanker to ensure that a delivery tube is evacuated to complete the delivery of a metered quantity of liquid fuel.

Road tankers for delivering liquid fuel are normally fitted with means for metering the liquid as it is discharged through a delivery tube. Whilst an accurate volume of the liquid is measured by the metering means during the delivery phase, any liquid remaining in the delivery tube at the end of this phase is not delivered and hence a customer does not receive the total metered amount. The invention seeks, inter alia, to solve this problem, since it may be more widely used to ensure that any material remaining in a delivery tube at the end of a delivery phase is displaced.

In general, the invention provides apparatus for delivering a quantity of fluent material via a delivery tube, the apparatus including means to evacuate the tube after a delivery phase in which most of said material has been delivered, said means being operative to introduce sufficient gas under pressure at the end of the delivery phase to displace any of the material remaining in the tube.

Preferably, the evacuating means responds automatically, after the delivery phase, to cause the gas to be introduced into the tube. However, the gas could be manually introduced, e.g. by means of a valve.

Preferably, the evacuating means discontinues the introduction of the gas after the material remaining in the tube has been displaced. In an automatic system, this advantageously terminates the supply of gas under pressure to the tube, e.g. when the tube is empty.

The apparatus may include metering means for measuring a predetermined quantity of the material to be delivered in the delivery phase, the evacuating means being actuated by the metering means after a predetermined quantity of the material has been measured. In a preferred embodiment of the invention, the evacuating means comprises a first valve for selectively connecting a source of gas under pressure to the tube, the first valve having a valve member which is movable between open and closed positions for respectively introducing and discontinuing the supply of the gas under pressure. For example, a spool valve with differential inputs may be employed.A second valve, such as a one-way trip/spring spool valve, connected to the source of gas under pressure, is actuated by the metering means after the predetermined quantity of the material has been measured in order to bias the valve member of the first valve into its open position. This causes the compressed air to be introduced into the discharge tube. A third valve, such as a pilot/spring spool valve, connected to the source of gas under pressure, is responsive to a loss of gas pressure downstream of the first valve in order to bias the valve member of the first valve into its closed position.Thus, as the pressurised gas drives the remaining material out of the discharge tube, it escapes to atmosphere thereby causing a loss of pressure in the discharge tube which automatically causes the first valve to close hence discos tinuing the supply of gas under pressure.

The apparatus may be advantageously fitted to a tanker vehicle from which material, such as liquid fuel, is delivered, the gas under pressure being derived from a compressed air supply on board the vehicle.

An example of the invention will now be described with reference to the accompanying schematic drawing which illustrates the main features of an embodiment of the invention.

Referring to the drawing, a meter outlet pipe 1 is connected at one end, via a non-return valve 2 and known metering means 3 to a tank 4 containing material to be delivered, such as liquid fuel. The metering means 3 includes a cam or lever 5 which actuates an operating lever 6 of a pilot valve 7 after a predetermined quantity of the liquid fuel has been measured. The pilot valve 7 is of known construction, the operating lever 6 having a trip tongue with a spring-loaded 1-way operation such that, when the metering means 3 is reset for a subsequent delivery, the pilot valve 7 is not operated (the function of the circuit is described in more detail below). The other end of the meter outlet pipe 1 is connected to a flexible hose 8 which terminates in a nozzle for location in a customer's tank prior to delivery of the liquid fuel.After a pre-determined quantity of the liquid fuel has been measured by the metering means 3, a certain quantity can remain in the meter outlet pipe 1 and part of the flexible hose 8 (hereinafter referred to as the delivery tube).

The wall of the pipe 1 is tapped to receive a threaded pipe 9 which is connected, via a non-return valve 10, to a pipe 11 for supplying gas under pressure, such as compressed air. The gas is derived from a source 12 such as the compressed air supply on a tanker vehicle which is normally used for operating, e.g. pneumatic brakes. The course 12 is connected via a valve 13, a filter/regulator 14 and an adjustable restrictor 15 to a spool valve 16. Valve 16 is provided with differential input ports 17 and 18 for admitting compressed air in order to move a valve member 19 between "open" and "closed" positions.

In the "open" position, an air inlet port 20 is connected to an air outlet port 22 for admitting the compressed air to tube 11 and hence the metering pipe 1 via the tapped inlet 9. In the "closed" position, the outlet port 22 is connected to a blind inlet port 23 thereby cutting offthe supply of compressed airto pipe 1.

Valve 13 may be operated to isolate the downstream system. Filter/regulator 14 filters the compressed air and enables its pressure to be set an an optimum operational value. Restrictor 15 enables further fine pressure regulation to be made.

Valve 7, which has been partly described above, includes ports 25,26 and 27. Port 25 is connected to a T-branch 28 upstream of valve 16. Port 26 is blind and port 27 is connected to the inlet port 17 of valve 16.

A pilotispring valve 29, of known construction, has ports 30 and 31 connected to respective T-branch connections 33,34 upstream and downstream of valve 16. Port 32 is connected to port 18 of valve 16.

Avalve member in valve 29 is spring-biased so as normally to open communication between ports 30 and 32.

The components within the outline 35 of the drawing may be conveniently housed within a casing.

In operation, after meter 3 has measured a predetermined quantity of liquid, lever 5 moves so as to actuate lever 6 on valve 7 thereby causing port 25 to communicate with port 27. This admits compressed airto port 17 of valve 16 thereby exerting pressure on one side of valve member 19. At this stage, valve 29 is open (ie port 30 communicates with port 32) and hence air pressure is also exerted on the other side of valve member 19. However, the pressure exerted via port 17 is greater than that exerted via port 18, due to the differential action of valve 16, and valve member 19 moves sufficiently to enable air to flow, for a short instant of time, from port 17 to port 22.This airflow acts on the valve member of valve 29, via a T-branch 34 and port 31, the air pressure being sufficient to overcome the spring-bias and to cause valve 29 to close (i.e, no communication between ports 30 and 32). This eliminates air pressure at port 18 and hence valve member 19 moves further to enable air to flow from port 20 to port 22 (i.e, valve 16 is then in its "open position"). Air under pressure then flows from source 12 into the delivery tube (1,8) so as to displace all of the liquid remaining in the tube, thus ensuring that all of the metered quantity is delivered (except for a neglible amount of wetness adhering to the inside of the tube).

After the "remaining liquid has been displaced from the tube (1,3), the air pressure decreases as the tube vents to atmosphere. This loss of pressure acts, via port 31, on the valve member of valve 29 to such an extent that the spring-bias (acting on this valve member) causes valve 29 to open thereby establishing communication between ports 30 and 32. Air under pressure then flows from the source 12 into the inlet port 18 of valve 16 to cause the valve member 19 to move in the opposite direction into its "closed" position thereby cutting off the supply of compressed air from source 12 to the pipe 1.No resistance is offered to such movement of valve member 19 at this time, because lever 6 on valve 7 is spring-loaded (see below) so as to return the valve 7 to its original state immediately after actuation by lever 5 of the metering means 3, ie after the measured quantity of liquid fuel has been measured.

This removes any air pressure input to port 17 of valve 16.

The metering means 3 is provided with a twostage type closure mechanism of known construction. The spring-loaded lever 6 of valve 7 is depressed in the first stage of closure, thus permitting the passage of air from port 25 to port 27. The lever 6 of valve 7 is released in the second stage of closure hence returning valve 7 to its original state. These two stages of closure occur after a predetermined quantity of liquid has been measured by means 3.

The predetermined quantity may be preset by a conventional mechanism of metering means 3 so that it closes off the supply of liquid to the delivery tube when the predetermined quantity has been measured. It will be noted that the system described above automatically returns to its original state in readiness for the next delivery phase.

Claims

1. Apparatus for delivering a quantity of fluent material via a delivery tube, the apparatus including means to evacuate the tube after a delivery phase in which most of said material has been delivered, said means being operative to introduce sufficient gas under pressure at the end of the delivery phase to displace any of the material remaining in the tube.

2. Apparatus according to claim 1, wherein the evacuating means responds automaticaly after the delivery phase to cause the gas to be introduced into the tube.

3. Apparatus according to claim 1 or 2, wherein the evacuating means discontinues the introduction of the gas after the material remaining in the tube has been displaced.

4. Apparatus according to any one of the preceding claims including metering means for measuring a predetermined quantity of said material to be delivered in the delivery phase, the evacuating means being actuated by the metering means after said predetermined quantity of material has been measured.

5. Apparatus according to claim 4 wherein said evacuating means comprises a first valve for selectively connecting a source of gas under pressure to the tube, the first valve having a valve member which is movable between open and closed positions for respectively introducing and discontinuing the supply of gas under pressure; a second valve which is actuated by the metering means, after said predetermined quantity has been measured, in order to cause the valve member of the first valve to move into its open position; a third valve which is responsive to a loss of gas pressure downstream of the first valve in orderto cause the valve member of the first valve to move into its closed position; and a non-return valve for admitting the gas under pressure to the delivery tube but preventing any reverse flow.

6. Apparatus according to claim 5 wherein the second and third valves are connected to and operated by the source of gas under pressure.

7. Apparatus according to claim 6 wherein the third valve is responsive to a loss of pressure derived from said source in order to move into an operative position to cause the valve member of the first valve to move into its closed position.

8. Apparatus for delivering a quantity of fluent material via a delivery tube substantially as herein described with reference to the accompanying drawing.

8. Apparatus according to any one ofthe preceding claims when fitted to a tanker vehicle from which the material is delivered, said gas under pressure being derived from a compressed air supply on board the vehicle.

9. Apparatus for delivering a quantity of fluent material via a delivery tube substantially as herein described with reference to the accompanying drawing.

New claims or amendments to claims filed on 20/7/84 Superseded claims 1 New or amended claims: New claim 1 Old claim 3 deleted, Original claims 4 to 9 renumbered as 3 to 8 and appendancies correspondingly re-numbered.

1. Apparatus for delivering a quantity of fluent material via a delivery tube, the apparatus including means to evacuate the tube after a delivery phase in which most of said material has been delivered, said means being operative to introduce sufficient gas under pressure at the end of the delivery phase to displace any of the material remaining in the tube and being responsive to a loss of gas pressure in the delivery tube to discontinue the introduction of the gas after the material remaining in the tube has been displaced.

2. Apparatus according to claim 1, wherein the evacuating means responds automatically after the delivery phase to cause the gas to be introduced into the tube.

3. Apparatus according to claim 1 or 2, including metering means for measuring a predetermined quantity of said material to be delivered in the delivery phase, the evacuating means being actuated by the metering means after said predetermined quantity of material has been measured.

4. Apparatus according to claim 3, wherein said evacuating means comprises a first valve for selectively connecting a source of gas under pressure to the tube, the first valve having a valve member which is movable between open and closed positions for respectively introducing and discontinuing the supply of gas under pressure; a second valve which is actuated by the metering means, after said predetermined quantity has been measured, in order to cause the valve member of the first valve to move into its open position; a third valve which is responsive to a loss of gas pressure downstream of the first valve in order to cause the valve member of the first valve to move into its closed position; and a non-return valve for admitting the gas under pressure to the delivery tube but preventing any reverse flow.

5. Apparatus according to claim 4 wheren the second and third valves are connected to and operated by the source of gas under pressure.

6. Apparatus according to claim 5 wherein the third valve is responsive to a loss os pressure derived from said source in order to move into an operative position to cause the valve member of the first valve to move into its closed position.

7. Apparatus according to any one of the preceding claims when fitted to a tanker vehicle from which the material is delivered, said gas under pressure being derived from a compressed air supply on board the vehicle.