US2055420A - Spring hydraulic motor for pressure recording bombs - Google Patents

Description

Sept. 22, 1936. r

.H. VISTEADMAN SPRING HYDRAULIC MOTOR For: PRESSURE RECORDING BOMB'S Filed April 21, 1934 2 Shets-She'et 1 7 Sept. 2Z, 1936. H. v. STEADMAN 'SPRING HYDRAULIC MOTOR FOR PRESSURE RECORDING BOMBS Filed April 21, 1934 2 Sheets-Sheet 2 m llllll IIWHI llllllll II lwwlo O 9 7 v 2W 9W1. .5 1 w w. xv?

lnvanTor= Horace Vivian fiT odman Patented Sept. 22, 1936 SPRING HYDRAULIC MOTOR FOR PRES- SURE RECORDING BOMBS Horace Vivian Steadman, Dallas, Tex., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application April 21, 1934, Serial No. 721,670

4 Claims.

This invention pertains to pressure recording gauges, particularly such as are used to measure pressure in wells, and has for its purpose to provide an improved spring hydraulic motor for the operation of such gauges. a

It is known in the art to record the pressure in wells by means of bombs lowered therein, and containing a strip of paper on which a stylus, connected to a helical tube of the Bourdon type communicable with the well, traces a line representing the well pressure, while another device, such as an electrical motor or a'clock mechanism, actuates the paper strip at a uniform rate, thus introducing the time element in the wellpressure graph.

Such devices, however, being of a more or less complex construction, are not always reliable in operation under the hard conditions of wear and tear prevailing. in deep well pressure measurements, and it is a purposeof this invention to replace them with a spring hydraulic motor of rugged construction and having a small number of simple and easily adjustable parts.

Further objects and advantages of the invention will become apparent from a consideration of the following description taken in connection with the accompanying drawings.

In thedrawings, Figs. 1, 2, 3 and 4 are vertical views, partly in cross-section, of four different embodiments of the spring hydraulic motor.

Fig. 5 is a horizontal cross-sectional view of the device taken along line A-A of Fig. 1.

Figs. 6 and 7 are horizontal cross-sectional views of the device taken respectively along lines AA and BB of Fig. 2.

Figs. 8, 9 and 10 are horizontal cross-sectional views of the device shown on Fig. 4.

Figs. 11 and 12 are horizontal cross-sectional views of the device shown on Fig. 3.

However, the applicant doesnot wish to limit himself to these particular types of construction, and may use any other embodiment to carry his invention into practice while retaining the sam principle of operation.

This principle consists in using a single or a multiple spring as a power-source, driving a piston through a cylinder completely filled with a more or less viscous liquid, the speed of the piston being regulated by the rate at which the liquid passes from one side of the piston within the cylinder to the other. This may be controlled in a number of different ways. For example, a fixed orifice may be mounted in the piston head; a groove of constant or varying cross-section may be cut in the wall of the cylinder; an orifice may be cut in the piston head so as to move over a central mandrel of constant or varying. cross-section, or a groove of constant or varying cross-section may be cut in the central mandrel. All these different ways will be discussed later.

All motors, illustrated in Figs. 1, 2, 3 and 4, consist of an outer shell I, closed by an upper head 2 and a lower head 3 screwed onto the threaded ends of the cylinder. The lower head carries a stufiing box fitted with a gland piece 1 and a gland nut 5 through which passes a piston rod 6.

Referring specifically to Fig. 1, there is shown within the cylinder and mounted on a piston rod 6, a piston I having an orifice nozzle 8, which is interchangeable and may be given any desired size, and a check valve 9. Above the piston is mounted a spring l0 seated against the upper cylinder head and piston respectively.

All free space above and below the piston is filled with a suitable liquid. In preparing the motor for use, the piston is forced for example, manually towards the upper end of the cylinder until the spring is fully compressed. In this operation the liquid trapped above the piston forces open the check valve against its spring and passes through to the under side of the piston. On release, the spring forces the piston downwards and, as the check valve has automatically closed, the liquid can return to the upper side of the piston only through the orifice in the nozzle. This latter, therefore controls the rate of flow in accordance with the pressure exerted by the spring and the viscosity and temperature of the fluid, and, consequently, controls also the rate at which the piston moves downwards.

Another way in which the spring-hydraulic motor may be constructed is shown in Fig. 2, and is identical to that of Fig. 1, with the exception that no orifice nozzle is provided in the piston-head. In place: of this there is cut in the cylinder wall a shallow groove II. This groove may be parallel-sided and of constant depth, parallel sided but of varying depth; of constant depth but with tapered sides, or in fact of any combination of depth and form of outline necessary to provide a constant or variable speed of travel of the piston and rod.

The operation of the motor in this case is similar to that discussed above,'with the exception that the liquid passes from the under to the upper side of the piston between the side of the piston and the wall of the cylinder through the 7 space provided by the groove in the cylinder the one just described, with the exception that wall.

Still another way of constructing the motor is shown in Fig. 3, where the upper part of the piston rod I2 is of hollow or tubular construction and the lower part 6 solid. In the upper end of the hollow portion are provided perforations IE to allow the fluid to pass between the cylinder and the inner space of the piston-rod. Attached to the upper cylinder head by a cap screw I 4 is a mandrel I6. This may be parallel sided or tapered to any desired profile. center of the mandrel is a passage 20 communicating with a chamber in which is mounted a check valve 9 seated against the passage through the cap screw M communicating through ports Him the walls of the mandrel with the'space above the piston.

In operation, when the piston is forced upwards, compressing the spring, the liquid above the piston passes through the ports I! in the top of the mandrel, to the passages in the cap screw, thence through the check valve 9 and the man- 'drel central passage 20 into the hollow piston rod, through the ports l5 therein and out into the cylinder beneath the piston.

On the spring forcing the piston down, the fluid passes to the top of the piston through the ports E5, the annular space I8 between the outer sur- 7 face of the mandrel and the opening through which the mandrel projects. By varying the contour of the mandrel [6 the escape of the fluid and the movement of the piston l and rod 6 may be made constant.

Fig. 4 shows a motor constructed similarly with the mandrel I6 is cylindrical and has in it a groove or a cut-away portion l9. This may be cut parallel to the axis of the mandrel or at an angle toitto provide either a constant or a progressively varying orifice for the passage of the fluid between the opening through the piston and. the surface of the mandrel.

A motor of any of the described types of construction may be mounted in a pressure-recording bomb, wherein the end of the piston rod 6 is attached to a vertically movable chart carrier, with a stylus or pen connected to the closed end of a Bourdon tube bearing against the chart.

The operation of the bore hole pressures recording bomb is as follows. With the vertical ,movement of the chart transmitted from the mo- Through the I claim as my invention:

1. In a well-pressure recording bomb, a piston rod for attaching a chart carrier, a spring hydraulic motor consisting of a hollow cylinder substantially filled with a liquid, a cylinder head, a piston rigidly connected to said piston rod, a spring braced against the cylinder head, and the piston, and means for producing a constant flow of the liquid from one side of the piston to the other when the piston is caused to move in the cylinder by the action of the spring.

2. The apparatus of claim 1, wherein the means for. controlling the flow of the liquid from one side of the piston to the other consists of a groove of increasing cross-section cut in the cylinder wall to allow the flow of the liquid when the piston is caused to move through the cylinder by the action of the spring.

3. In a well-pressure recording bomb, a hollow piston rod for attaching a chart-carrier, a piston head attached to said piston rod, a springhydraulic motor comprising a hollow cylinder substantially filled with a liquid, a cylinder head, a spring braced against the cylinder-head and the piston-head, and means to control the flow of the liquid from one side of the piston to the other when the piston is caused to move through the cylinder by the action of the spring, said means comprising a mandrel of varying crosssection attached to the cylinder head, a central passage in said mandrel, an orifice in the piston head leaving an annular opening around the mandrel, a check valve and perforations in the upper part of said mandrel communicating with the cylinder space above the piston, and perforations in the walls of the hollow piston-rod communicating with the cylinder space below the piston.

4. In a well-pressure recording bomb, a hollow piston rod for attaching a chart-carrier, a piston cross-section having a groove of varying crosssection cut in it attached to the cylinder head, a central passage in said mandrel, an orifice in the piston head leaving an annular opening around the mandrel, a check valve and perforations in the upper part of said mandrel communicating with the cylinder space above the piston, and perforations in the walls of the hollow piston-rod communicating with the cylinder space below the piston.

HORACE VIVIAN STEADMAN.

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