DE2649490C2 - Safety device for a loading arm consisting of several mutually movable sections - Google Patents

Description

The invention is based on a safety device according to the preamble of the main claim.

Articulated booms are used in the oil industry, for example, to transport oil between a fixed line or an attachment on a pier bridge or an oil tanker anchored to the pier. In DE-PS 14 56 606 an articulated boom or a loading arm is generally described, which is a on one Essay held first section, for example, around a horizontal and a vertical axis can be pivoted, and a second section connected to the first section, the two

For example, it can be pivoted about a horizontal axis with respect to the first section. The end of the second section of such a bearing arm can be connected to any manifold which is arranged within the area of the bearing arm

From DE-OS 25 09 401 a device for limiting the working range of cranes is known, the crane being provided with only a single boom. This device comprises a device to stop the crane boom, which then comes into operation when the boom reaches its working range limit reduced scale on an opaque material which is then set by photosensitive Sensors is scanned, which then emit a signal, is when the boom emerges from the work area The work area is in this known arrangement determined and not by the presence of fixed obstacles, such as buildings you rch the load on the crane boom.

When designing an articulated boom for transporting oil between a fixed line and a Oil tankers are subject to minimum conditions for the area of the articulated boom -

These conditions are maximum within the limits Relocation of a tanker parallel to or away from the mooring bridge in relation to a basic position that must be taken into account, a further maximum offset away from the system bridge due to the changes in the distance between a tanker manifold and the tanker rail, which must be taken into account and a maximum vertical displacement due to the changes the water level and the changes in the height of a tanker manifold opposite the water level, which must also be taken into account. Thus, a three-dimensional space is limited which is rectangular in section in plan view or either parallel or right-angled in side view This three-dimensional space is known as the limited operating area and the Articulated boom must be able to connect to a manifold at any point within the To be connected to the operating area.

The articulated arms are balanced by a counterweight so that they are essentially self-supporting when empty. In operation and when filled with a flowable medium, for example with oil, however, the weight of the oil is not weight-balanced and it has to be supported in part by the collecting line to which the arm is connected. The load on the manifold increases with the extension of the boom. In addition, the tanker headers normally point towards the tank rail and the load they can be subjected to in a direction perpendicular to the rail and therefore perpendicular to the docking bridge is increased when the boom moves another component into a position at an angle to the Bridge or to the ship's railing is initiated. The load parallel to the railing increases when the angle between the vertical plane in which the boom lies and the vertical to the edge of the contact bridge increases. This angle is known as the pivot angle. In order to prevent the loads on the collecting line from exceeding safety limits ^; ten, the extension of the boom and the swivel angle must be limited.

In order to achieve this, arrangements are provided for triggering an alarm in the event that the angle between the first and second sections exceeds a predetermined limit value or in the event that the pivot angle exceeds a predetermined limit. These independent limits result in operating characteristics which are incomplete sufficient because they effectively limit a space within which the boom can work, which is limited either by curved surfaces or by planes that go through the vertical pivot axis of the first boom section on the bridge. Thus, if a certain rectangular operating area has to be taken into account, there are fairly extensive areas outside the operating area also within the operating range of the boom and the loads that occur when the boom end is in these areas outside the operating area can substantially exceed those within of the operating range.

The task of the invention is therefore to create a safety device that prevents ν> ~ The joint outrigger leaves a given three-dimensional space in order to avoid overloading.

This object is linked by the characterizing features specified in claim 1 council solved the features of the generic term

The safety device according to the invention continuously monitors the position of the end of the Bearing arm or the connecting device and compares them with predeterminable limit values, wherein then an alarm is triggered when the limit values are exceeded, that is, when the boom end moves outside a predetermined space The scanning devices for determining an angle determine the direction of the attached on a fixed holder preferably from two sections existing loading arm around a vertical pivot axis and / or its inclination to the horizontal. In addition, the relative orientation of the sections or the inclination of the second section, for example to the vertical, can be determined. The scanning devices can be mechanical in nature, but are preferably electrical in nature, for example those which generate electrical signals indicative of the orientation of the sections. The scanning devices can have either analog or digital outputs. By a corresponding modification and / or Combination of the electrical signals, for example by amplification and summing, can be a composite Signal can be generated that can be compared to a reference signal to determine whether the boom end is still within the predetermined Räumet or outside

Ir. «Jen subclaims are measures for advantageous further training and improvement of the According to the invention specified safety device.

An embodiment of the invention is shown in the drawing and is based on the following Description explained in more detail It shows

F i g. 1 is a schematic view along a landing stage on which an articulated boom is held;

F i g. 2 is a schematic plan view of the articulated boom of Figs. 1 and

Fig. 3 to 8 individual features of a system that generally with reference to FIG. 1 and 2 is described.

In Fig. 1 and 2, an articulated boom is shown, the a first section 1 has the pivotable at 2

'is connected to a fixed line in a support 3 The articulated boom also has a second section 4, which at 5 with the first section I. is pivotally connected and at its end pivotably has a connecting device 6 for a connection with a tanker manifold is carried out. The entire articulated boom device is open a mooring bridge 7, which is equipped with a flexible fender 8.

In Fig. 1 through line 9 is the main sea water level and the high and low water lines are indicated by dash-dotted lines on either side of the Line 9 shown. The facility is designed to accommodate various tankers and tanker movements during of the charging operation must be taken into account. The "operating area" is defined and by the levels tO, 11, 12,13,

14 and 15 (Figs. I and 2).

The freedom of movement between levels 10 and

11 in the horizontal direction away from the pier 7 is indicated by a section 11, of the changes in the distance between the manifold and railing of different tankers represents and by a section I2, which the permissible movement of the tanker towards the jetty and from this way represents

The freedom of movement between planes 12 and 13 in the vertical direction is for changes of the water level as well as for changes in the height of the tankers and for changes at the height of the tanker manifold above the sea level when the tanker is full.

The freedom of movement between levels 14 and

15 is given for the permissible movements of the tanker parallel to the mooring bridge.

To take into account the permissible freedom of movement, it must be for the connecting device 6 on the Articulated booms be able to reach a manifold that is somewhere within the three-dimensional Space is arranged by vertical planes 10, 11, 14 and 15 and by horizontal planes

12 and 13 is limited

F i g. 1 shows the directions of sections 1 and 4 when the boom is arranged in a plane at right angles to the edge of the landing bridge and the connecting device 6 is arranged in each of the four corners of the rectangle formed by planes 10, 11, 12 and 13 that when an indication is to be given when the connecting device 6 moves beyond the plane 11, for example, it is necessary to monitor the angles α and β. If only one of the angles is monitored, it would not be possible to determine the plane 11 in order to determine if the connecting device 6 moves beyond this plane moved away.

F i g. Fig. 2 shows the directions of sections 1 and 4 (Fig. 1) when the connecting device 6 is attached to each the points of intersection between planes 10, 11, 12 and

13 is arranged. Assuming that the connecting device 6 (F i g. I) is located at the intersection of the planes 11 and 15, any increase in the tilt angle γ brings the connecting device 6 beyond the plane 15 without a retraction of the boom. Although the component of the load in the vertical plane on the manifold behind the plane 15 would not be greater than if the connecting device were arranged at the intersection of the planes 11 and 15, the component of the load parallel to the vertical face of the jetty 7 would be increased and therefore the entire combination of loads is not permitted. Since tanker collecting lines always point towards the tanker rail, this component creates a shear force and a bending moment that can damage the collecting lines.

The dashed areas in FIG. 1 are areas outside the operating range into which the connecting device 6 could move if the angle changes while the angle β is maintained at the fixed value shown.

The dashed areas in FIG. 2 are areas outside the operating range into which the connecting device 6 could be moved if the angle γ is changed while the angles <% and β are maintained at the fixed values shown.

In order to obtain the desired indication when the connecting device 6 moves outwards over the three-dimensional space delimited by the planes 10, 11, 12, 13, 14 and 15, sensors are arranged in order to produce an indication for the direction of the section 1 to monitor the angle α in relation to the support 3 in order to monitor the angle β for an indication of the direction of the section 4 in relation to the section 1 and to monitor the tilt angle γ . The sensors can have various transformers, for example potentiometers or other devices for supplying analog outputs, or a series of limit switches for supplying digital output values. When using potentiometers, the track of the potentiometer can be connected to section 1 and the wiper of the potentiometer to member 4, for example. The signals indicating the angles λ, β and γ are combined to form a combination signal or to indicate the position of the connecting device 6.

Known electronic techniques can be used to modify the signals supplied by the sensors can be used, for example, to obtain a voltage signal indicating that the connecting device 6 is within three-dimensional space when the voltage signal is below a predetermined threshold value remains and for the opposite an indication is given if the signal is above the Threshold is located. The voltage signal can be used to set various alarm devices trigger.

3 and 4 further show a schematic side view and a schematic top view of the articulated boom of FIG. 1 and 2. The geometry of the articulated boom is shown from which the position of the boom end in space can be reached. The first section 1 has a known length a, the second section a known length b, and the variable distance between the perpendicular lines drawn through point 2 and through connector 6 is shown as d. The coordinates x, .y and ζ count from connection point 2 as shown

The device works by measuring the angles λ, β and γ, with synchronous coordinate converters being used to obtain direct measured values of cos a, sin ft, cos (/? - «}, sin {ß- <%), cos γ and siny . The distance d is calculated from the

relationship

(D

rf = β cos a + b cos 08-α)
and χ and y become from the ratios

10

calculated.
The distance ζ is derived from the ratios

ζ- -αsin β + 6 sin 08-α)

(4)

15th

calculated.

Each of the values x, y and ζ is calculated, compared with the specified limits and an alarm is triggered if any limit is exceeded. The circuits that perform these operations are detailed below.

Fig. 5 is a block diagram of a complete circuit for monitoring the position for actuation of the alarm. It consists of an oscillator 16 which produces a sine wave output 17 with a peak-to-peak value of three volts at 400 Hz and a square wave output 18 with zero to twelve volts at 400 Hz. The output 17 is passed to a first resolver 19 which scans the angle λ and generates 400 Hz outputs 20, 21 and 22, the amplitudes of which are modulated to represent cos <x, are α and λ, respectively. A second resolver 23 scans the angle β and further modulates the output 22 from the first resolver to generate 400 Hz outputs 24 and 25 to represent cos (β-d) and sin (^ - <%). The resolvers are well known devices. Small phase shifts in the 400 Hz drive waveform that occur in the resolvers are corrected by capacitance switching. ·

A first feedback summing amplifier 26 sums the cosine signals 20 and 24 with results, each proportional to a / (a + b) and b / (a + b) to generate an output 27 that is representative of d / (a + b) . The distances a , fc, and d are compared with respect to the maximum distance, ie (a + b) possible in the system, to ensure maximum accuracy. A second feedback summing amplifier 28 sums the sinusoidal signals 21 and 25 with results, each proportional to a / (a + b) and so b / (a + b) to generate an output 29 representative of z / (a + b). A third Resolver 30 determines the angle γ and generates for dsin y / (a + ty representative outputs 31 and 32, ie x / (a + b) and d cos yl (a + b), ie y / (a-rb) for one first and a second phase detector 33 and 34. The signal 29, ie z / (a + b) is fed to a third phase detector 35

Each phase detector 33, 34 and 35 is through the square wave output 18 of the oscillator 16 to Conversion of its input into a direct current signal operated, the direct current signal being a respective Comparator 36, 37 or 38 is supplied. The comparators take each negative and positive Reference signals from a fourth phase detector 39, which is also through the square wave output 18 of the Oscillator 16 is operated. These reference signals are used within the comparator to form maximum and minimum values for the signals given to the comparators by the detectors 33, 34 and 35 set and the comparators form outputs for an OR gate 40 whenever the input signals in addition lie outside the maximum and minimum values. The OR gate 40 provides some comparator output to an alarm circuit not shown in FIG.

In Fig. 6 are the oscillator 16 and phase detector 39 of FIG. 5 shown in detail.

The oscillator consists of an active filter 41 of the second order, which is connected together as a cascade with an integrator 42. A feedback controlled by a potentiometer 43 ensures automatic starting and a symmetrical output. A Schmitt trigger 44 driven directly by the sine wave output 17 of the oscillator generates a reference signal 18 with a square wave (0-12 V) for the phase detector 39. Positive and negative direct current reference voltages are obtained from the phase detector 39, which operates on the square wave reference signal 18. This ensures that any changes in the reference drive for the resolvers 19, 23 are tracked by the x, y and ζ reference limits. The operation of the phase detector is monitored by a transistor switch 45 to which the signal 18 is fed.

7 shows the summing amplifiers 26 and 28, the resolver 30 and the phase detectors 33, 34 and 35 in detail. The amplifiers 26 and 28 are of standard shape and they are precision potentiometer 46 at each of the entrances. Their outputs are in the form of amplitude-modulated sine waves of 400 Hz.

The output 27 of the summing amplifier 26 is resolved into its x and y components by a transformer arrangement 47, amplified by feedback amplifiers 48 'and routed to the phase detectors 33 and 34. The output of the summing amplifier 28 is routed directly to the detector 35. The detectors 33 , 34 and 35 operate in the same way as that in FIG. Detector 39 shown in FIG.

Each of the phase detectors 33, 34 and 35 receives a square-wave input signal directly from the oscillator anyway 16 and a composite sine and / or cosine input signal derived from the signal of the Oscillator 16 is derived via resolvers 19, 23 and 30. This composite input signal must be "scanned" in order to obtain a suitable DC voltage signal for the comparator 36,37,38 to come. Since the sine «signal, apart of the phase difference is identical to the cosine α signal, the sampling must be carried out as a function of the phase. This phase scanning is carried out in such a way that at certain times, beyond the rectangular Output signal of the oscillator 16 are determined, the composite respective input signal is sampled will. In each phase detector 33,34,35,39 controls the square-wave voltage a transistor switch 45, which the sampled composite input signal a differential amplifier which supplies a DC voltage output signal The phase detector 39 compensates the system if there is a phase drift between sinusoidal and square-wave output signals of the oscillator 16 should occur.

The comparator 35 is shown in FIG. 8. The comparators 33 and 34 are identical. The reference limits are based on the positive and negative DC reference values obtained by potentiometer 48.

The in Fig. The calculated signal 29 shown in FIG compared these reference values, with functional amplifier 49 with a high gain and open Control loop can be used. If any limit is exceeded, the corresponding amplifier output will be greater than +3 V. This is used by one in Fig. 8 OR gate diode, not shown to switch on an Alar ™ itransistor. A positive one The effect is achieved through the use of a ß-C network with a short rise time and a long fall time in this OR gate ensured. The alarm transistor may, for example, be a pair of hermetically sealed Apply reed relay contacts to actuate additional alarm systems.

The device described can be used for different sizes of boom. Selected Signals can be made available at an external junction box so that they can be supplied to each boom associated constants can be set. This adjustment usually takes place with the arrangement of the boom in a certain mechanical form.

When working with several articulated booms, either one boom can be designated as the main unit or alarm devices are provided which are actuated when any of the booms exceeds its set limits during operation

In the arrangement described, the distances a, b. d etc. related to the maximum length (a + b) of the boom fixed on the scale. If mechanical stops prevent the boom from exceeding a length that is less than (a + b) .

this shorter length can be used to set the scale to achieve greater accuracy be used.

The above description relates to a system in which three angles, β and y are monitored. In some cases it is possible that only angles β and γ need to be monitored if changes in angle are found to be negligible for the load.

This depends on the geometry and the requirements of certain systems. In addition, the angle ό shown in FIG. 1 can be monitored in order to obtain an indication of the direction of the section 4 relative to the vertical. This angle can be monitored in addition to the three angles λ, β, γ or as an alternative to one of these angles or in combination with one of these angles. For example, knowing the angles β and δ provides essential information for the position of the connecting device 6.

It should be noted that angles other than those mentioned above can be monitored.

The system described continuously monitors the position of the connecting device 6 and compares with predetermined limits, with an alarm being triggered if the limits are exceeded. The signals generated by the monitoring device can be used to represent the boom position can be used on a corresponding receiving unit, which always shows the actual Position of the connecting device 6 in the room at a remote location.

In addition 6 sheets of drawings

Claims (1)

Claims; 1. Safety device for a loading arm consisting of several mutually movable sections for the transfer of a flowable medium from a non-stationary collecting line into a stationary pipeline, a first section of the loading arm being attached to a stationary bracket of the stationary pipeline and being connected to the pipeline that it can be pivoted about a horizontal axis, and a second section of the loading arm with its free outer end has the connecting device 2 for the collecting line, characterized by a first scanning device (resolver 19) for determining a first angle, which determines the orientation of the first section (1) of the loading arm with respect to the horizontal axis indicates by a second scanning device (resolver 23) for scanning an angle β or two angles β and γ, which determines the relative orientations of the adjacent second section (4) of the loading arm, and by evaluating devices (summing amplifiers 26, 28) that transmit the data of the scanned angles in the associated position x, y, ζ of the outer end and thus the connecting device (6) of the loading arm (1, 4) in the permissible operating range with respect to the fixed bracket (support 3 ), the range of motion of the permissible operating range being determined by a device (amplifier 39) in a manner known per se by comparing the determined values with predetermined reference values in the form of limit values 2. Safety device according to claim 1, characterized by resolvers (19, 23, 30) for generating electrical signals (20, 21, 22, 24, 25, 31, 32) representative of the scanned angles tx, β, γ by a circuit (Summing amplifier 26, 28) for calculating from the electrical signals of further signals (27, 29) which are necessary for the positions of the loading arm end (connecting device 6) with respect to the pivotable holder (2, 5) of a section (1) are representative in space, by means (amplifier 39) for Generation of reference signals that represent the limits over which the loading arm end (connecting device 6) should not be moved out, and by a comparison device (36, 37, 38) to compare these further signals with the reference signals and to activate an alarm circuit (OR gate 40) in the event that the limits are exceeded. 3. Safety device according to claim 2, characterized by a first resolver (19) for scanning the inclination «of the first section (1) relative to the horizontal, by a second resolver (23) for scanning the inclination β of the first section (1) relative to the second section (4) and by a third resolver (30) for scanning the inclination γ of the first section (1) with respect to a vertical plane. 4. Safety device according to claim 3, characterized in that the first resolver (19) has an output (19) indicating the inclination <x and the inclination a. indicating output (22) for the second resolver (23) and cos α and sin λ indicating outputs (20,2t) for a first and second summing amplifier (26 and 28), the second resolver (23) for cos β - emits α and sin β-λ prospective outputs (24, 25) for the first and second summing amplifier, respectively 5. Safety device according to claim 4, characterized in that the first summing amplifier (26) the cos "and cos β - λ inputs (20,24) reinforced with the results proportional to the length (a) tu of the first section (1) or the length (b) of the second section (4), the amplified inputs are summed to form a signal (27) indicating the horizontal distance (d) between the ends (2, 6) of the loading arm and the summed signal to the third resolver (30) directs. 6. Safety device according to claim 5, characterized in that the third resolver (30) outputs (3t, 32) indicating d - sin <x and d · cos α for the first and second phase detectors (33, 34) and that the second summing amplifier (28) amplifies the sin oil and sin ρ - α inputs (21,25), the results being proportional to the length of the first section (a) and to the length of the second section (b) , the amplified inputs to the formation a signal indicating the vertical distance (z) between the end of the loading arm (6) is summed and the summed signal (29) is passed to a third phase detector (35), the outputs of the first, second and third phase detectors (33, 34, 35) being the Specify the x, y or z coordinates of the end of the loading arm (connecting device 6). 7. Safety device according to claim 6, characterized in that the output of the Phase detectors are given to respective comparators (36, 37, 38), each of which receives positive and negative reference signals from a fourth phase detector (39). 8. Safety device according to claim 7, characterized by an OR-Gi.tter (40) with the outputs of the three comparators (33, 34, 35) are connected to an alarm circuit in the event can switch on that any comparator emits an output signal. 9. Safety device according to one of claims 7 or 8, characterized in that the first Resolver (19) and the fourth phase detector (39) from an oscillator (16) have a first sine wave output record and that each of the four phase detectors (33, 34, 35, 39) operated by a square wave output of the oscillator (16) will.