RU2321831C2 - Sensor for control and signaling about border of interface between mediums petroleum product-water - Google Patents

Abstract

FIELD: invention refers to control-measuring technique and is assigned for control and signaling about border of interface between mediums petroleum product-water in installations for purification water from petroleum products or watered petroleum products from water.

SUBSTANCE: sensor has flange, three electrodes with sleeves on their low ends filled with fresh water, moreover two of them are covered with dielectric insulation. Electrodes with sleeves are located inside tube of protective screen and are fastened in flange with aid of stuffing boxes-insulators. Screen in upper part has diaphragm ring with openings along circumference coinciding with openings in screen forming swinging compensator and is fastened to flange with aid of screws. Electrodes of sensor together with sleeves and electronic part form oscillating contour going in resonance at presence in space between electrodes of electric conductive medium (water) with following triggering of executive elements and at presence of water between electrodes of petroleum product resonance of contour stops.

EFFECT: increases reliability of work of sensor.

2 cl, 1 dwg

Description

The invention relates to measuring and control equipment and is intended for signaling and monitoring the upper and lower position of the oil-water medium interface, generating a control signal and outputting it to the automatic control system of oil-water separation plants and in other cases, for example, for controlling the water-air interface .

Contact level sensors are known whose operating principle is based on the closure of an electrical circuit when the sensor electrodes are immersed in a controlled fluid.

A control device is known that contains an electrode with a glass in the lower part filled with pure water, an electrode insulator, and a container body in which a controlled oil-water medium is located (USSR, AS No. 144,42837, class G01F 23/24, is used as the second electrode). )

Closest to the proposed design is a device for monitoring and signaling the position of the boundary of the media of oil-water (Eurasian patent No. 001683 dated 03/28/2001, class G01F 23/24).

The specified design contains a flange with gaskets-insulators, electrodes with cups coated on the outside with insulation, filled with clean water and placed in a protective screen with a diaphragm ring, an electrode cleaning system made in the form of one or more vertical tubes with holes along the entire length, the lower end of which made of gear and mounted on a conical baffle-reflector located in the lower end of the screen tube, and the upper one is connected to the inlet radial channel made in the flange and equipped with a prop knym valve. The electrodes are made different in length and the upper end is fixed by means of glands-insulators in the flange, and one of the electrodes, which is common and connected to the flange without an insulator, is equipped with an additional glass with clean water mounted at the level of the glass of the short electrode.

This design has several disadvantages, which include:

1. The complexity, bulkiness and unsatisfactory efficiency of the system for cleaning electrodes from oil products, the deposition of salts, mechanical particles;

2. The check valve requires careful lapping and, as a rule, does not provide tightness;

3. With a large length of the electrodes under the influence of vibration and pitching, the distance between the electrodes changes, which leads to a change in the resistance of the conductive medium and, as a consequence, to false responses of the device;

4. The glasses are connected to the electrodes using threads, and Grover washers are used to lock them. In seawater, the washers break down and the glasses spontaneously unscrew from the electrodes upon vibration;

5. A common electrode having two glasses is relatively difficult to manufacture, and a second upper glass is not required;

6. When the salinity of the water between the electrodes with glasses changes, the magnitude of the current between the electrodes changes, and this leads to instability of the device;

7. When the controlled medium is heated, the electrical conductivity changes, which leads to false positives of the device.

The purpose of the invention is to improve the design, increase reliability and eliminate the noted disadvantages.

This goal is achieved in that the sensor contains a flange with holes around the perimeter for fastening it to the neck of the tank or separator, over which the lid is fastened with a stud and nut, three electrodes with glasses filled with clean water and placed at their lower ends, while the upper level electrode and the long lower level electrode are fixed in the flange by means of gaskets-insulators, the third - the common electrode - is made of the same length as the lower level electrode, the protective screen in the form of a short pipe, nenny in the upper part with a flange, and the electrodes with the glasses are placed inside the screen, having in the upper part a diaphragm ring with holes matching the holes on the screen tube, mounted to rotate to change the bore of the holes with the formation of the pitching compensator, and the third electrode is also attached in the flange with an insulating gland, while the glass of the upper level electrode and the glass of the lower level electrode are coated with dielectric insulation from the outside, all glasses are attached to the electro am by threads, the stopper lock nuts and fixed to the screen via one or more spacers of a dielectric material, wherein the bottom end of the screen is set coarse protective mesh. In addition, the electrodes with glasses with clean water together with the electronic part form an oscillatory circuit that enters into resonance in the presence of an electrically conductive medium (water) between the electrodes and leads to a breakdown of resonance in the presence of a dielectric medium (oil product).

The openings of the screen and the diaphragm ring provide free transfusion of the oil-water medium and are blocked by the diaphragm ring when it rotates up to 95% of the full bore, as a result, the screen with holes and the diaphragm ring with holes form a false positive compensator during rolling of the ship while protecting electrodes with glasses from mechanical particles, viscous and sticky oil nodules.

To prevent spontaneous unscrewing of the glasses from the electrodes during vibration, locknuts are provided, and for a more accurate fixation of the upper and lower oil-water media interfaces, the glasses of the upper (short electrode) and lower position (long electrode) are coated with dielectric insulation from the outside, and the general (long) glass the electrode does not have such a coating.

The electrodes in the upper part are mounted in the flange using insulating glands, thereby ensuring tightness and dielectric isolation between the electrodes and the flange.

To prevent vibrations of the electrodes with cups during vibration and rocking of the ship, one or more spacers of dielectric material are provided.

The drawing shows the design of the sensor. The sensor contains a flange 1 with holes 2 around the perimeter for mounting in a vertical position to the neck of the separator or tank, glands-insulators of electrodes 3, a diaphragm ring 4 with holes 5, a protective screen 6, which is an open pipe at the bottom with a protective coarse mesh 9, connected by screws in the upper part with flange 1, glasses 10 with dielectric insulation 11, electrodes 12, terminals of electrodes 13, cover 14, stud with nut 15. Electrodes 12 are mounted with upper ends in flange 1 by means of glands-insulators 3, p Passing over the flange in the terminal 13 and at the lower ends of the electrodes threadedly attached cups 10, the locking against inadvertent loosening lock nuts 7. Beakers 10 upper and lower level electrodes 11 covered with dielectric isolation, and the glass of the common electrode has no dielectric insulation. In order to prevent rocking during vibration and rocking of the ship, the electrodes are fixed with one or more stops 8. Terminals 13 of the electrodes 12 are protected from foreign objects by a terminal cover, which is consumed by a stud with a nut 15.

The sensor is based on the electrical conductivity of water with the formation, together with the electronic part of the resonant oscillatory circuit, in the presence of water between the electrodes with glasses.

The sensor operates as follows. Before starting work, the glasses 10 of the electrodes 12 are filled with clean water, the sensor in the vertical position with the help of the flange 1 is fixed on the neck of the separator or reservoir, in which the controlled oil-water medium is located, and a current with a certain frequency and voltage is supplied to the terminals 13.

When filling the separator or reservoir with oil-water medium, the lower part of the sensor to the flange is also filled with medium, and with the subsequent separation of the medium into water and oil product, the space between the electrodes 12 with glasses 10 is filled with water or oil. In the oil-water medium, the glasses 10 always contain pure water, preventing contamination of the inner surface of the glass and part of the electrode in it, and when the oil-water phase boundary rises, the glass mirror is freed from the oil product. When filling the space between the electrodes 12 with the glasses 10 with water, the electric circuit closes, the oscillating circuit formed by the electrodes and the electronic part of the sensor resonates, the maximum current begins to flow along the circuit and the corresponding actuator is activated. As the boundary drops, the oil product-water phases separate the oil product covers the mirror of the glasses 10 (first the upper and then the lower ones) and the electric circuit breaks, the resonance stops in the oscillating circuit, the current in the electric circuits of the circuit decreases to 0 and vice versa. In the oscillatory circuit, a variable is mainly the resistance of the medium between the electrodes with cups, then decreasing to very small values in the presence of water, then increasing to a very large value (almost to infinity) in the presence of an oil product.

When the ship is rolling and the separator or tank placed in it with a “lens” sensor, the oil product separated from the water in them, trying to occupy a horizontal position, will synchronously swing, moving in a vertical plane with a certain amplitude and period, depending on the rolling force, and the oil product in the internal the cavity of the screen 6 of the sensor will synchronously repeat the movement of the main "lens" of the oil product, moving from the internal or internal cavity of the screen through the holes 5 of the screen 6 and the diaphragm ring 4, together uyuschih compensator false positives when the ship rolling. Compensation of false responses of the sensor during ship rolling occurs due to throttling of the oil product when it flows through the adjustable bore of the holes 5 in the screen 6 and the diaphragm ring 4 when it is turned around early and locked by the screw. By turning the diaphragm ring 4, based on the viscosity of the oil product, experimentally select such a passage section of the holes 5 such that the time of the oil product flowing from the cavity of the sensor screen 6 into the “lens” and vice versa is significantly behind the time of moving the main “lens” of the oil product in the separator or tank, and the amplitude of the oscillations of the oil product in the cavity of the screen 6 is significantly less than the amplitude of the oscillations of the "lens" of the oil in the separator or tank, which leads to a decrease in false responses of the sensor.

The invention provides a clear, reliable control of the position of the oil-water phase interface when the ship is rolling up to ± 45 ° for a period of 2 ... 9 s and when the temperature of the controlled medium changes.

Claims (2)

1. A sensor for monitoring and signaling an oil-water medium interface, comprising a flange with mounting holes, over which a lid is mounted using a stud and nut, three electrodes with glasses filled with clean water and placed at their lower ends, with a short electrode of the upper the level and the long electrode of the lower levels are fixed in the flange by means of gaskets-insulators, the third - the common electrode - is made of the same length as the electrode of the lower level, a protective screen in the form of a short pipe connected to the upper part a flange, and the electrodes with cups are placed inside the screen having a diaphragm ring in the upper part with holes matching the holes on the screen tube, mounted for rotation to change the bore of the holes with the formation of a pitching compensator, characterized in that the third electrode is also mounted in the flange using an insulating gland, while the glass of the upper level electrode and the glass of the lower level electrode are coated with dielectric insulation on the outside, all glasses are attached to the electrodes with threads, they are locked with locknuts and fixed in the screen using one or more spacers of dielectric material, and a coarse-mesh protective net is installed on the lower end of the screen. 2. The sensor according to claim 1, characterized in that the electrodes with glasses with clean water together with the electronic part form an oscillatory circuit that enters into resonance in the presence of an electrically conductive medium (water) between the electrodes and leads to a breakdown of resonance in the presence of a dielectric medium (oil product) .