GB1573365A

GB1573365A - Rotary irrigation sprinklers

Info

Publication number: GB1573365A
Application number: GB29903/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-07-19
Filing date: 1977-07-15
Publication date: 1980-08-20
Also published as: AT344435B; BR7704753A; GR66042B; ZA774091B; IT1084335B; YU178877A; AU512847B2; ATA531676A; FR2358931A1; IN147514B; FR2358931B1; AU2690777A; IL52510A0; CA1087651A; JPS5334398A; ES460826A1; DE2729451A1

Description

(54) IMPROVEMENTS IN OR RELATING TO ROTARY IRRIGATION SPRINKLERS (71) I, GERHARD BRANDL, an Austrian citizen, of Leonhardstrasse 79, A 8010 Graz (Steiermark), Austria, do hereby declare the invention, for which I ray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement; The present invention relates to a rotary irrigation sprinkler and is concerned more particularly with a rotary irrigation sprinkler of the type which comprises a stationary tubular housing having an axis and an axially extending inner surface, a water delivery pipe mounted in the housing for rotation therein and a water outlet pipe connected to the water outlet of the inlet pipe for rotation with the delivery pipe, the outlet pipe being provided with a nozzle for sprinkling the discharged water. The delivery pipe of this type of sprinkler has an axially extending outer surface which forms with the axially extending inner surface of the housing a plain journal bearing between the stationary housing and the rotatable inlet pipe. It also has a water inlet at one end thereof for receiving water from a source of water pressure and a water outlet at the other end thereof for discharging the water under pressure when the inlet is in communication with the water source, the reaction force or back pressure of the discharged water causing the water inlet pipe to rotate about the axis.

Rotary irrigation sprinklers used in agriculture for sprinkling water over a growing crop must rotate slowly to ensure proper watering of the crop, i.e. at no more than a few revolutions per minute.

Conventional sprinklers of this type are usually provided with a pivoted member. In small sprinklers, this pivoted member periodically interrupts the water jet and thus imparts a periodic impact to the sprinkler nozzle through a given angle. Usually, the rotating mechanism is so arranged tha the sprinkler nozzle turns once about the axis in a period of about a minute. The rotary angle per impact is about 2" and is limited by the friction of the bearing. In many conventional small sprinklers of this general construction, a spring-biased plastic disc provides additional braking of the rotary motion.

In large sprinklers, the pivoted member is usually arranged so that it periodically passes through the water jet and, while so doing, laterally deflects the water jet, as a result of which a thrust is imparted to the rotatable parts of the sprinkler so that they rotate through an angle of about 1". Braking is again required to limit the angle of rotation and various brake means have been proposed, most of them designed to assure one full rotation per three or four minutes.

It has also been proposed to drive rotary sprinklers without the provision of such a pivoted member by obliquely positioning the water outlet nozzle. In such sprinklers, a friction brake is not sufficient since it would either completely stop the rotation of the rotatable parts of the sprinkler or permit it to rotate much too fast. Therefore, geared pumps have been provided as brakes for these sprinklers. The braking force of these geared pumps is approximately proportional to the rotary speed, and a slow and uniform rotation of the sprinkler is obtained when the nozzle is disposed at an angle of about 10 .

The omission of the pivoted member saves costs, on the one hand, but the braking means is relatively expensive, on the other hand.

It is the primary object of this invention to provide a rotary irrigation sprinkler which avoids the costs of a pivoted member as well as an expensive braking system while ensuring slow and uniform rotation of the sprinkler.

With this object in view, there is provided according to one aspect of this invention a rotary irrigation sprinkler comprising a stationary tubular housing having an axis and an axially extending inner surface, a water delivery pipe mounted in the housing for rotation therein, the delivery pipe having an axially extending outer surface, a water inlet at one end of the delivery pipe for receiving water from a source of water under pressure, and a water outlet at the other end of the delivery pipe for continuously discharging the water under pressure when the inlet is in communication with the water source, the reaction force of the discharged water causing the water delivery pipe to rotate about the axis, the said axially extending inner and outer surfaces forming a plain journal bearing between the stationary housing and the rotatable inlet pipe, a highly viscous lubricant, as herein defined filling the bearing between the said axially extending surfaces, the viscosity of the lubricant being such that the resistance of the bearing to the rotation of the delivery pipe in operation is approximately directly proportional to the rotary speed of the delivery pipe, and a water outlet pipe connected to the water outlet for rotation with the delivery pipe, the outlet pipe being provided with a nozzle for sprinkling the discharged water.

According to another aspect of this invention, there is provided a rotary irrigation sprinkler comprising a stationary tubular housing and a water delivery pipe mounted coaxially in the housing for continuous rotation under the reaction force of water flowing through the delivery pipe under pressure and discharged therefrom through an outlet pipe which is connected to the delivery pipe for rotation therewith and is provided with a nozzle for sprinkling the discharged water, the outer surface of the delivery pipe and the inner surface of the housing forming a plain journal bearing and this bearing being filled with a lubricant which is so viscous that the resistance of the bearing to the rotation of the delivery pipe is approximately directly proportional to the rotary speed of the delivery pipe.

The high viscosity of the lubricant sufficiently brakes the rotary movement of the rotatable parts of the sprinkler to make provision of a mechanical braking system unnecessary. This simple construction makes it economically possible to build even small sprinklers without a pivoted member of the kind referred to above because the sprinklers of the present invention are cheaper to manufacture than the conventional sprinklers with such a pivoted member. Furthermore, they are more compact and are less sensitive to damage in rough agricultural use than sprinklers provided with such a pivoted member.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a rotary irrigation sprinkler according to the invention; Figure 2 is an axial section of the sprinkler of Figure 1; and Figure 3 is a section taken on the line III III in Figure 2.

The sprinkler shown in the drawings comprises a stationary tubular housing 1, which has an axially extending inner surface 3 and a water delivery pipe 2 mounted coaxially in the housing 1 for rotation with respect thereto. The delivery pipe 2 has an axially extending outer surface 4, the surfaces 3 and 4 forming a plain journal bearing between the stationary housing 1 and the rotatable delivery pipe 2.

The stationary tubular housing 1 has an external screw-thread 13 at an inlet end thereof for screw-threaded attachment to a feedpipe (not shown). The feedpipe is in communication with a source of water under pressure. The water delivery pipe 2 has a water inlet at the end thereof which is adjacent the inlet end of the housing 1 to receive the water under pressure when the housing is connected to the water source, and a water outlet at the other end thereof for discharging the water under pressure. The reaction force or back pressure of the water discharged through a bent water outlet pipe II, when the latter is suitably disposed, causes the water delivery pipe 2 to rotate about its axis, as explained hereinafter.

The delivery pipe 2 is held in position in the housing 1 against axial displacement by an annular shoulder 9 engaging a matching abutment in the housing 1 at one end while a ball bearing 6 in an annular groove 5 in the housing 1 rotatably supports the delivery pipe 2 at the opposite end.

The outlet end of the delivery pipe 2 has an external screw-thread 14 for screw-threaded attachment with a connecting member 10, a ball bearing 7 being arranged between the facing ends of the stionary housing 1 and the connecting member 10 to enable the connecting member to rotate with the delivery pipe 2. The connecting member 10 carries the radially extending water outlet pipe 11 which is mounted therein by means of a ball bearing 12 and the outer end of the water outlet pipe 11 is provided with a water sprinkling nozzle 8. The rotatable mounting of the water outlet pipe 11 in the connecting member 10 permits repositioning of the nozzle 8 in any desired position.

Water under pressure flows through the axial bore of the delivery pipe 2 into the axial bore in the connecting member 10 which is in communication with the axial bore in the outlet pipe 11 to discharge the flowing water through the nozzle 8 which sprinkles a water jet over the ground. By rotating the water outlet pipe in the direction of the arrow A in Figure 1, the direction of the discharged water jet can be changed, causing a corresponding change in the direction of the reaction force or back pressure of the water and hence in the direction of rotation of the delivery pipe 2 together with the connecting member 10 and the outlet pipe 11.

As shown in Figure 2, the outer surface 4 of the water delivery pipe 2 is formed with an axially extending groove 15 for receiving a lubricant. The entire space between the surfaces 3 and 4, which form a plain journal bearing, is filled with a very viscous lubricant.

The viscosity of the lubricant is such that the resistance of the bearing to the rotation of the delivery pipe 2 is approximately directly proportional to the rotary speed of this pipe.

Throughout the specification and claims, the term "highly viscous lubricant" is used to mean a lubricant which produces a frictional resistance directly proportional to the rotary speed, which is equal to or in excess of the bearing friction. The bearing friction is independent of the rotary speed and is determined essentially by the friction of the gaskets and the sliding surface characteristics of the bearing surfaces 3 and 4.

Economically suitable lubricants meeting this standard are oil or oil-bitumen mixtures having a viscosity of 5000 to 500,000 centistokes at 200, preferably 20,000 to 40,000 centistokes.

A sprinkler constructed as described above with reference to and as illustrated in the drawings and having the space between the surfaces 3 and 4 thereof filled with a lubricant having a viscosity of 40,000 at 20 , and which was operated at a water pressure of 6 atmospheres, recorded a rotary speed of one revolution per 3 to 4 minutes. When the temperature of the water was raised to 300C, the viscosity of the lubricant decreased to about 18,000 centistokes, changing the rotary speed to one revolution per 1.5 to 2 minutes. On the other hand, reducing the water temperature caused the viscosity of the lubricant to rise. At a water temperature of 10 C, the rotary speed of the rotatable parts of the sprinkler was about one revolution in about 8 minutes.

WHAT I CLAIM IS: 1. A rotary irrigation sprinkler comprising a stationary tubular housing having an axis and an axially extending inner surface, a water delivery pipe mounted in the housing for rotation therein, the delivery pipe having an axially extending outer surface, a water inlet at one end of the delivery pipe for receiving water from a source of water under pressure, and a water outlet at the other end of the delivery pipe for continuously discharging the water under pressure when the inlet is in communication with the water source, the reaction force of the discharged water causing the water delivery pipe to rotate about the axis, the said axially extending inner and outer surfaces forming a plain journal bearing between the stationary housing and the rotatable inlet pipe, a highly viscous lubricant, as herein defined, filling the bearing between the said axially extending surfaces, the viscosity of the lubricant being such that the resistance of the bearing to the rotation of the delivery pipe in operation is approximately directly proportional to the rotary speed of the delivery pipe, and a water outlet pipe connected to the water outlet for rotation with the delivery pipe, the outlet pipe being provided with a nozzle for sprinkling the discharged water.

2. A rotary irrigation sprinkler according claim 1, wherein the lubricant is oil.

3. A rotary irrigation sprinkler according claim 1, wherein the lubricant is a mixture of oil and bitumen.

4. A rotary irrigation sprinkler according to claim 1, wherein the viscosity of the lubricant is 5000 to 500,000 centistokes at 20"C.

5. A rotary irrigation sprinkler according to claim 4, wherein the viscosity of the lubricant is 20,000 to 40,000 centistokes at 200 C.

6. A rotary irrigation sprinkler according to claim 1, wherein an axially extending groove is formed in the outer surface of the water delivery pipe for receiving the lubricant.

7. A rotary irrigation sprinkler comprising a stationary tubular housing and a water delivery pipe mounted coaxially in the housing for continuous rotation under the reaction force of water flowing through the delivery pipe under pressure and discharged therefrom through an outlet pipe which is connected to the delivery pipe for rotation therewith and is provided with a nozzle for sprinkling the discharged water, the outer surface of the delivery pipe and the inner surface of the housing forming a plain journal bearing and this bearing being filled with a lubricant which is so viscous that the resistance of the bearing to the rotation of the delivery pipe is approximately directly proportional to the rotary speed of the delivery pipe.

8. A rotary irrigation sprinkler substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figure 1, the direction of the discharged water jet can be changed, causing a corresponding change in the direction of the reaction force or back pressure of the water and hence in the direction of rotation of the delivery pipe 2 together with the connecting member 10 and the outlet pipe 11. As shown in Figure 2, the outer surface 4 of the water delivery pipe 2 is formed with an axially extending groove 15 for receiving a lubricant. The entire space between the surfaces 3 and 4, which form a plain journal bearing, is filled with a very viscous lubricant. The viscosity of the lubricant is such that the resistance of the bearing to the rotation of the delivery pipe 2 is approximately directly proportional to the rotary speed of this pipe. Throughout the specification and claims, the term "highly viscous lubricant" is used to mean a lubricant which produces a frictional resistance directly proportional to the rotary speed, which is equal to or in excess of the bearing friction. The bearing friction is independent of the rotary speed and is determined essentially by the friction of the gaskets and the sliding surface characteristics of the bearing surfaces 3 and 4. Economically suitable lubricants meeting this standard are oil or oil-bitumen mixtures having a viscosity of 5000 to 500,000 centistokes at 200, preferably 20,000 to 40,000 centistokes. A sprinkler constructed as described above with reference to and as illustrated in the drawings and having the space between the surfaces 3 and 4 thereof filled with a lubricant having a viscosity of 40,000 at 20 , and which was operated at a water pressure of 6 atmospheres, recorded a rotary speed of one revolution per 3 to 4 minutes. When the temperature of the water was raised to 300C, the viscosity of the lubricant decreased to about 18,000 centistokes, changing the rotary speed to one revolution per 1.5 to 2 minutes. On the other hand, reducing the water temperature caused the viscosity of the lubricant to rise. At a water temperature of 10 C, the rotary speed of the rotatable parts of the sprinkler was about one revolution in about 8 minutes. WHAT I CLAIM IS:

1. A rotary irrigation sprinkler comprising a stationary tubular housing having an axis and an axially extending inner surface, a water delivery pipe mounted in the housing for rotation therein, the delivery pipe having an axially extending outer surface, a water inlet at one end of the delivery pipe for receiving water from a source of water under pressure, and a water outlet at the other end of the delivery pipe for continuously discharging the water under pressure when the inlet is in communication with the water source, the reaction force of the discharged water causing the water delivery pipe to rotate about the axis, the said axially extending inner and outer surfaces forming a plain journal bearing between the stationary housing and the rotatable inlet pipe, a highly viscous lubricant, as herein defined, filling the bearing between the said axially extending surfaces, the viscosity of the lubricant being such that the resistance of the bearing to the rotation of the delivery pipe in operation is approximately directly proportional to the rotary speed of the delivery pipe, and a water outlet pipe connected to the water outlet for rotation with the delivery pipe, the outlet pipe being provided with a nozzle for sprinkling the discharged water.