GB1574309A

GB1574309A - Slurry tanker

Info

Publication number: GB1574309A
Application number: GB1787576A
Authority: GB
Original assignee: Massey Ferguson Perkins Ltd
Current assignee: Perkins Engines Group Ltd
Priority date: 1976-05-01
Filing date: 1976-05-01
Publication date: 1980-09-03
Also published as: FR2349271A1; IE44874B1; FR2349271B1; IE44874L

Description

(54) SLURRY TANKER (71) We MASSEY-FERGUSON PERKINS LIMITED, a British Company, of 33 Davies Street, London, W1Y 2EA do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to slurry spreading apparatus that is to say, to apparatus capable of spreading or spraying liquids comprising water in which is dispersed a solid material such as waste products from intensive animal husbandry. Such liquids can vary in viscosity or consistency from a viscosity much the same as that of water itself to the viscosity of a runny or flowable porridge.

More particularly, the invention relates to slurry spreading apparatus having an air pump and a tank into which slurry is drawn bv causing the pump to evacuate the tank and from which slurry is expelled (and spread over the ground by any suitable means such as a nozzle and a deflector plate) by subsequently causing the pump to pressurize the tank containing slurry. Such apparatus is known in the art as a "slurry tanker''.

In such slurry spreading apparatus, it has already been proposed to provide a float valve within the tank. the valve being responsive to the rise of liquid within the tank above a predetermined level during filling of the tank and operative to cut off communication between the main tank and the air pump when said level is reached. In this way the valve is intended to prevent the passage of liquid slurry into the air pump, which obviouslv is not intended to handle such material and is liable to be damaged thereby.

However. such float valves are not, on their own. effective to fully protect the air pump against the ingress of foreign material, since although the float of the valve will float on water or slurry it is not lifted by the froth or foam frequently formed when slurry is sucked into the tank. Therefore when a layer of froth forms above the slurry during filling of the tank, the float valve can remain open while significant quantities of the froth are sucked into the air pump. The valve only shuts when the liquid level itself reaches the necessary height.

It has already been propsed to provide a secondary tank or froth tank between the main tank and the air pump, to trap the froth and reduce the likelihood of its carryover into the pump. It is an object of the present invention to provide slurry spreading apparatus having an improved arrangement of a secondary or froth tank.

According to the invention there is provided slurry spreading apparatus comprising a main tank to contain slurry; ground wheels to support the main tank, and a drawbar whereby the apparatus can be drawn by a tractor; inlet and outlet means in the main tank to permit inflow and outflow of slurry; an air pump for selectively supplying air to and evacuating air from the main tank; and a secondary tank connected to the air pump and to the pressure tank to permit evacuation of air from the main tank by the air pump through the secondary tank characterized in that the secondary tank is located within the main tank.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a slurry tanker in side elevation and partly cut away; Figure 2 shows a perspective view from the front and one side of the slurry tanker of Figure 1; Figure 3 shows a perspective view of the tanker as seen from the rear and with the rear end of the slurry tank opened to show a froth tank therein; and Figure 4 is an elevation view of a baffle of which three are shown mounted within the slurry tank in Figure 1, but which are not included in the tanker shown in Figure 3.

The principal structures of the slurry spreading apparatus will be identified first and then described in detail.

As shown in the drawings, slurry spreading apparatus in the form of a slurry tanker 10 comprises a main tank 12 to contain slurry, a pair of ground wheels 14, 16 to support the main tank and a drawbar 18 whereby the tanker can be drawn by a tractor (not shown). A parking stand 19 is mounted on the drawbar.

Main tank 12 is cylindrical in form and is arranged with its longitudinal axis extending in the direction D of usual forward motion of the slurrv tanker. The tank has convex front and rear end walls 20, 22 respectively.

An air pump 24 for selectively supplying air to and evacuating air from main tank 12 is mounted on drawbar 18 in front of front end wall 20 and a secondary tank or froth tank 26 is mounted within main tank 12 and is connected to air pump 24 by a first pipe 28, and is connected to the main-tank by a second pipe 30.

Inlet and outlet means 32 is provided in main tank 12 to permit the inflow and outflow of slurry, the inlet and outlet means comprising a nozzle assembly 34 connected to the main tank through a gate valve 36 and a port (not shown) formed in the rear tank wall 22. a deflector plate 38, and a suction pipe 40.

Having identified the principal structures of a slurrv tanker 10, these will now be described kvith such detail as is appropriate in each case.

Main tank 12 is mounted on- ground wheels 14. 16 through longitudinal beams 42. welded one to each side of the tank. An axle 44 on which the wheels are journalled is secured to beams 12. Drawbar 18 is secured to the forward ends of beams 42.

The rear end wall 22 of main tank 12 is mounted on heavy duty vertical axis hinges 46, 48 (see Figure 3) so that the whole near end of the tank can be swung open to give access to the interior for cleaning or other purposes. An annular seal (not shown) is mounted on rear wall 22 and is held in sealing engagement with the rear edge of the cylindrical side wall of the main tank 12 by a series of heavy dutv pivoted clamps 50 (see Figures 2 and 3) each having a manuallv operable screw device 52 which abuts the near side of wall 22 when the rear wall is closed.

Air pump 24 has a shielded drive input shaft 54 having an internally splined sleeve 56 to receive a tractor power take-off shaft, and universal joints 58, 59, one at each end.

The pump comprises a rotor (not shown) mounted at an eccentric position within a cylindrical pump chamber, the rotor having a single pair of diametrically opposed vanes urged outwardly by - springs. A manually operable change-over valve 60 mounted on pump 24 and connected to pipe 28, has a control handle 62 whereby pipe 28 can be connected either to the suction side or the pressure side of the pump according to whether it is desired to evacuate or pressurize main tank 12. In the "evacuation" position of the valve, the suction side of the pump is connected to pipe 28 and the pressure side to atmosphere and in the "pressure" position of the valve these connections are reversed.

Froth tank 26 is cylindrical in form and is mounted on and sealed to front wall 20 of main tank 12 so as to be coaxial with the main tank. Thus the main tank and the froth tank share, a common wall. That is to say, the central portion 63 of the front wall 20 of the main tank forms the front wall of the froth tank and the cylindrical side wall 64 of the froth tank is sealed thereto.

The rear end wall 66 of froth tank 26 is flat and is welded to the side wall 64 thereof.

The diameter of end wall 66,is the same as the diameter of the internal edge 67 of each of three part-annular baffles 68. 70, 72 -which are mounted within main tank 12 and project inwardly from the inside surface of the tank to reduce liquid surge within the.

tank during use. The baffles are shown in Figures 1 and 4 only, and are fo.rmed by a stamping operation. The disc stamped out from the centre of each baffle can be used as an end wall of a froth tank 26 thereby economizing on materials used. Each baffle has a space between its ends 74. 76 through which slurry can run, thereby permitting as complete emptying of the main tank 12 as possible. In this connection it should be noted that in the usual working attitude of the tanker, the tank 12 slopes slightly downwards (about 2 degrees) towards the rear to promote more complete emptying.

Front wall 63 of froth tank 26 has openings formed therein to receive: a sight glass 78 for observing the interior of tank 26; and a pressure relief valve 80 to release pressure from the main tank 12 upon the pressure therein rising above a predetermined level; and first pipe 28 leading to air pump 24, and a drain pipe 82 having a manuallv-operable drain control valve 84 to control the discharge of trapped froth from the froth tank through the drain pipe. Drain pipe 82 opens into the bottom end of the froth tank and first pipe 28 opens into the top end of the tank.

Second pipe 30 communicates at one end 86 with froth tank 26 and extends upwardly from the froth tank through the cylindrical side wall of main tank 12, and its other end 88 is located outside the main tank and communicates through a float valve 90 with the main tank.

Float valve 90 comprises a housing 91 mounted on top of main tank 12 and opening into the main tank. A cut-off valve member 92 is connected by a stem 94 to a float 96 within the main tank. rtem 94 is slidably received within guides -f8 whereby float 96 can lift valve member 92 against a valve seat 100 to cut off communication between pump 24 and main tank 12 upon the rise of liquid within the main tank above a predetermined level.

Within froth tank 26, second pipe 30 extends downwards sufficiently for its end 86 to be at a significantly lower level within the froth tank, than the end 102 of first pipe 28 from air pump 24. This minimizes direct carry-over of froth between the two pipes.

Two further sight glasses 104 and 106 are mounted in end walls 20, 22 respectively of main tank 12 to permit the liquid level within the tank to be inspected.

Nozzle assembly 34 is pivotally mounted on an inlet'outlet pipe 108 leading from gate valve 36. by means of a hinge 110 so that the nozzle assembly can be swung into and out of the spreading position shown in Figure 1.

Deflector plate 38 is mounted on the nozzle assembly through a fixed arm 112 and swings into and out of the spreading position with the nozzle assembly. The deflector plate itself is pivotally mounted on arm 112 and its working position is defined by an adjustable cam 114.

Nozzle assembly 34 is held in its spreading position shown in Figure 1 by a quick attach and release coupling 116 having toggle action hooks mounted on inlet/outlet pipe 108. Coupling 116 permits the nozzle assembly to be quickly disconnected and the end 118 of suction pipe 40 to be connected up to enable main tank 12 to be filled as will be described.

Gate valve 36 is biased by a spring 120 to its closed position and is provided with a hand ! r. er 122 and a remotely operable hydraulic ram (not shown) for opening it.

In use, the drawbar 18 of slurry tanker 10 is connected to the drawbar clevis or hook of a tractor and drive input shaft 54 is connected to the tractor's power-take-off shaft.

First, air pump 24 is caused to evacuate main tank 12 by drawing air through float valve 90. second pipe 30. froth tank 26, and first pipe 28. Valve 90 is held open by gravity. The tank i7 can be evacuated during transport of the tanker to the filling site to save time.

When the main tank 12 has been evacuated (e.g. to a pressure of about one fifth of an atmosphere i.e. 2.9 p.s.i.) by the air pump 24 - as indicated by a pressure gauge 124 or by the sound of the pump - suction pipe 40 is connected to inlet/outlet pipe 108 and the free end of the suction pipe is immersed in (for example) a slurry lagoon.

Gate valve 36 is then opened and slurry flows into the main tank. Air pump 24 is kept running gently, to maintain the vacuum in the tank.

If a significant amount of froth is formed in the tank as the tank fills, the froth will eventually reach a level at which it can pass through float valve 90 and enter froth tank 26. However since the froth tank is relatively large and since the end of first pipe 28 is at its upper end, froth does not pass through to the air pump, but is trapped in the bottom of the froth tank.

As soon as the liquid in main tank reaches a level near the top of the tank and closes float valve 90, the operator hears a change in the note of the pump 24 or notices the pressure change in pipe 28 (as indicated by gauge 124), and closes gate valve 36 and interrupts the p.t.o. drive to pump 24.

The main tank 12 is now full of slurry and the slurry tanker 10 is drawn by the tractor to the site where the slurry is to be spread.

When it is desired to start spreading, the drive to air pump 24 is recommenced by engaging the p.t.o. drive with change-over valve 60 in its "pressurize" position. Air is supplied to main tank 12 via froth tank 26 and float valve 90, and relief valve 80 opens almost immediately at a pressure of about 1.2 atmospheres (about 17.5 p.s.i.). Gate valve 36 is then opened by remote control using its ram, and a jet of slurry hits deflector plate 38 and forms the characteristic fan-shaped spray pattern. The tanker is drawn over the land as spreading proceeds, until main tank 12 is empty. Air pump 24 maintains the pressure in the tank at about 1.2 atmospheres throughout the spreading operation. The tank 12 can then be refilled as described above.

If froth tank 26 is nearly full of froth after filling main tank 12, it can be emptied by putting change-over valve 60 in its pressurized position, closing gate valve 36 and opening drain valve 84 whereupon the froth will be ejected through drain pipe 82 by air from pump 24.

Advantages provided by the embodiment of the invention described above include the following: 1. the froth tank can be made relatively large without obstructing the front end of the implement, thereby providing improved froth protection for pump 24 with only a relatively small sacrifice of capacity of the main tank; 2. the pressure relief valve 80 protecting main tank 12 against over-pressurization is mounted in the common front wall 63 of both the froth and main tanks and thereby is able to protect the main tank adequately without being exposed to the slurry therein.

The valve is thus more reliable in operation than valves which are exposed to the materials present in slurry; and 3. since the froth tank 26 is located inside the main tank 12, the froth tank is subjected to much lower pressure differentials than if it were located outs 5e the main tank. This allows the froth ta',, to be of lighter construction (and therefore lower cost) than otherwise.

Among modifications which can be made in the above described embodiment which nevertheless fall within the scope of the claims, are the following: 1. the use of a separate connecting pipe between change-over valve 60 and main tank 12 for pressurization of the tank; 2. the use of a separate slurry inlet pipe with its own gate valve, in addition to valve 36. pipe 108 and nozzle 34: 3. the use of other types of float valve in place of valve 90: 4. the use of a second pressure relief valve in main tank 12, the valve being mounted, for example. adjacent float valve 90: 5. the use of other types of spreading apparatus in place of nozzle 34 and deflector plate 38. for example a rotary spreading device.

WHAT WE CLAIM IS: 1. Slurry spreading apparatus comprising: a main tank to contain slurrv: ground wheels to support the main tank, and a drawbar whereby the apparatus can be drawn by a tractor: inlet and outlet means in the main tank to permit inflow and outllow of slurrv: an air pump for selectively supplying air to and evacuating air from the main tank: and a secondary tank connected to the air pump and to the main tank to permit evacuation of air from the main tank bv the air pump through the secondary tank characterized in that the secondary tank is located within the main tank.

2. Slurry spreading apparatus according to Claim 1 characterized in that the secondary tank and the main tank share a common X all.

3. Slurrv spreading apparatus according to Claim 2 characterized in that said common wall is the front wall of the main tank having regard to the direction of usual forward motion of the apparatus.

4. Slurry spreading apparatus according to claim 3 characterized in that the secondary tank is cylindrical in form.

5. Slurry spreading apparatus according to claim 4 characterized in that said main tank is cylindrical in form and is positioned with its longitudinal axis extending in the direction of usual forward motion of the apparatus, the main tank having a convex rear end wall and a convex front end wall, and the secondary tank having a convex front end wall formed by a portion of the front end wall of the main tank and a cylindrical side wall sealed to the front wall of the main tank.

6. Slurry spreading apparatus according to any of claims 2 to 5 characterized by a sight glass provided in said common wall for observing the interior of the secondary tank.

7. Slurry spreading apparatus according to any of claims 2 to 6 characterized by a pressure relief valve provided in said common wall to release pressure from the main tank upon the pressure therein rising above a predetermined level.

8. Slurry spreading apparatus according to any preceding claim characterized in that the connection between the secondary tank and the main tank comprises a pipe having one end communicating with the secondary tank and its other end being located outside the main tank and communicating with the main tank through an opening formed in an upper portion of the main tank.

9. Slurry spreading apparatus according to claim 8 characterized bv a float valve located within the main tank and adjacent said opening in the main tank. the valve being operative to close said opening upon the rise of liquid within the main tank above a predetermined level.

10. Slurry spreading apparatus according to claim 8 or claim 9 characterized by a pipe connecting the air pump to the secondary tank. and by the end of the pipe between the secondary tank and the main tank being at a lower level within the secondary tank than the end of the pipe connecting the air pump to the secondary tank.

11. Slurry spreading apparatus according to any of claims 2 to 6 characterized by a drain pipe communicating through said common wall with the interior of the secon darv tank. and a drain control valve operable to control the discharge of trapped liquid or froth from the secondary tank through the drain pipe.

12. Slurry spreading apparatus according to claim i or claim 5 characterized by a baffle secured within the main tank and projecting inwardly from the inside surface of the main tank to reduce liquid surge within the tank. the baffle being partannular in form and the diameter of the internal edge of the baffle being substantially the same as the diameter of the rear wall

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 2. the pressure relief valve 80 protecting main tank 12 against over-pressurization is mounted in the common front wall 63 of both the froth and main tanks and thereby is able to protect the main tank adequately without being exposed to the slurry therein. The valve is thus more reliable in operation than valves which are exposed to the materials present in slurry; and 3. since the froth tank 26 is located inside the main tank 12, the froth tank is subjected to much lower pressure differentials than if it were located outs 5e the main tank. This allows the froth ta',, to be of lighter construction (and therefore lower cost) than otherwise. Among modifications which can be made in the above described embodiment which nevertheless fall within the scope of the claims, are the following:

1. the use of a separate connecting pipe between change-over valve 60 and main tank 12 for pressurization of the tank;

2. the use of a separate slurry inlet pipe with its own gate valve, in addition to valve 36. pipe 108 and nozzle 34:

3. the use of other types of float valve in place of valve 90:

4. the use of a second pressure relief valve in main tank 12, the valve being mounted, for example. adjacent float valve 90:

5. the use of other types of spreading apparatus in place of nozzle 34 and deflector plate 38. for example a rotary spreading device.

of the secondary tank.

13. Slurry spreading apparatus substantially as described herein and as illustrated in Figure 1 of the accompanying drawings.

14. Slurry spreading apparatus substantially as described herein and as illustrated in Figure 1 taken together with Figures 2 and 3 and 4 of the accompanying drawings.