RU2176782C2 - Gas odorizer - Google Patents

Abstract

FIELD: transportation of natural gas. SUBSTANCE: gas odorizer can be employed at gas distribution stations for fixed injection of odorant ( ethyl mercaptan ) into gas pipe-line carrying gas to populated areas to impart it with specific odor to detect possible leaks. Gas odorizer incorporates control unit, metering cylinder fitted with mobile stepped piston dividing metering cylinder into metering chamber of controllable volume connected to working vessel, chamber of command pressure and intermediate chamber and throttle. Chamber of command pressure communicates with high-pressure source and intermediate chamber through controlled three-way electromagnetic valve and working vessel, metering and intermediate chambers are connected to odorized gas pipe-line. Mobile piston unit comes in the form of two uniaxial pistons of larger and smaller diameters mounted for axial movement of one piston relative to another piston by controlled value. EFFECT: prolonged working life of gas odorizer. 2 dwg

Description

 The invention relates to a technique for transporting natural gas and can be used at gas distribution stations (GDS).

 In accordance with industry standards, natural gas supplied to settlements from GDS is odorized, i.e. As a safety measure, in order to give the gas a specific odor to detect possible leaks, a normalized odorant (ethyl mercaptan) is introduced into the gas pipeline in proportion to the gas flow.

 Known gas odorizer [1], which contains a working tank, a control unit and a metering device based on a two-way solenoid valve, through which, by an electric command supplied with a given frequency by the control unit, an odorant from the working tank by gravity enters the gas pipeline. However, the capabilities of the known odorizer are limited at extreme values of the gas flow range.

 Known gas odorizer [2], which is the prototype of the claimed, which contains a control unit, a working capacity, a metering cylinder, equipped with a movable step piston that separates the metering cylinder into a metering chamber of adjustable volume connected to the working tank, a command pressure chamber and an intermediate chamber, a throttle, moreover, the command pressure chamber is connected through a controlled three-way solenoid valve to a high pressure source and an intermediate chamber, and the working capacity, dosing and industrial diate odoriruemym chamber connected to the pipeline.

 The known odorizer by adjusting the frequency and dose, as well as introducing an odorant by injection under pressure, has high technical characteristics over the entire range of gas flow rates. At the same time, as shown by operating experience, such a property of the odorizer as durability [3] determines the most loaded element of the odorizer - a three-way solenoid valve, whose durability is less than the durability of all other elements of the odorizer.

 The aim of the invention is to increase the durability of the gas odorizer.

 This goal is achieved by the fact that in the known gas odorizer, which contains a control unit, a working tank, a metering cylinder, equipped with a movable piston device that separates the metering cylinder into a metering chamber of variable volume connected to the tank, a command pressure chamber and an intermediate chamber, an orifice, moreover, the command pressure chamber is connected through a controlled three-way solenoid valve with a high pressure source and an intermediate chamber, and the working capacity, dosing and the intermediate chamber is connected to the odorized gas pipeline, according to the invention, the movable piston device is made in the form of two coaxial pistons of larger and smaller diameters, mounted with the possibility of axial movement of one piston relative to the other by an adjustable stroke value.

 The invention is illustrated by drawings, where in FIG. 1 schematically shows a gas odorizer; in FIG. 2 is a diagram of its installation on a GDS.

 The odorizer contains a working tank 1 with an odorant, a metering cylinder 2, an inlet 3 and an outlet 4 non-return valves, a three-way solenoid valve 5, a control unit 6 with a solenoid valve, a throttle 7, pipelines 8, 9, 10, 11. On the gas distribution system, pipe 8 is connected to the gas pipeline high pressure 20, i.e. to the throttle assembly 21, which reduces the gas main pressure to a value specified by the consumer, and pipelines 9, 10, 11 are connected to the odorized gas pipeline 22.

 The metering cylinder 2 contains a movable piston device made in the form of two coaxial pistons 12 and 13 separating the cylinder into a command pressure chamber 14, a metering chamber 15 and an intermediate chamber 16, a spring 17, adjustable stops 18 and 19.

 A piston 12 of a larger diameter (large area) is located between the chambers 14 and 16, a piston 13 of a smaller diameter (smaller area) is located between the chambers 15 and 16, and the volume of the chamber 14 is much larger than the volume of the chamber 16. The pistons 12 and 13 are mounted axially the displacement of one piston relative to the other by an adjustable amount A, limited on one side by a stop 24 rigidly connected to the piston 12 and a stop 25 rigidly connected to the piston 13, on the other hand by the end face 23 of the piston 12 and the adjustable stop 19.

 The gas odorizer works as follows.

 By means of an adjustable stop 19, size A is set, the value of which determines the working stroke of the piston 13, corresponding to the dose of odorant required for one injection into the odorized gas pipeline 22.

 By means of an adjustable stop 18, size B is set, the value of which determines the stroke of the piston 12, corresponding to the dose of odorant required for two injections.

 The control unit 6 gives an electric command to turn on the three-way solenoid valve 5, when activated, the command pressure chamber 14 communicates with the high pressure supply pipe 8 and disconnects with the intermediate chamber 16. In this case, the piston 12 moves downward relative to the piston 13 under the action of the gas command pressure by the value A, during which the stop 24 moves away from the stop 25 and after the end face 23 touches the stop 19, both pistons move together as a unit until the end of the piston 12 rests on the end face 26, i.e. by an amount equal to the difference between the values of B and A, displacing (injecting) the dose of the odorant from the chamber 15 through the outlet valve 4 through the pipe 11 into the odorized gas pipeline 22. The inlet valve 3 is thus closed.

 After a certain period of time, determined by the program of work of the control unit 6, the unit gives a command to turn off the solenoid valve 5, which disconnects the chamber 14 from the pipeline 8 and communicates it through the camera 16, the throttle 7 through the pipeline 10 with an odorized gas pipeline 22. The gas located under high pressure in the chamber 14, it enters the intermediate chamber 16, and under the action of pressure from the chamber 16, the piston 13 moves down until the stop 25 contacts the stop 24, i.e. by a value A, displacing (injecting) a dose of odorant from the chamber 15 through the exhaust valve 4 through the pipe 11 into the gas pipeline 22. The intake valve 3 is thus closed. In the process of reducing the pressure in the chamber 14 when bleeding gas through the throttle 7 to a value at which the total force from the pressure on the pistons 12 and 13 from the side of the chamber 16 and the spring 17 will exceed the force on the piston 12 from the side of the chamber 14, the piston 12 and located with it at the stop 25, the piston 13 together, as a whole, will move up to the stop of the piston 12 at the stop 18, i.e. by B.

 In the process of movement of the pistons upward through the inlet valve 3 with the exhaust valve 4 closed, from the working tank 1, which is under pressure from the gas pipe 22, the dosage chamber 15 is filled with an odorant.

 When applying to the solenoid valve the following commands for turning it on and off, the program of which is determined by setting the control unit 6 depending on the gas flow, the dosed odorant input cycle is repeated.

 Thus, for one cycle of operation of the electromagnetic valve 5, two odorant injections are performed: the first when turned on, the second when turned off, which doubles the durability of the odorizer.

 Obviously, to ensure uniform input of the odorant, the value of B, which determines the stroke of the piston 12, is set equal to twice the value of A, which determines the stroke of the piston 13, which ensures the equality of the injected doses when the electromagnetic valve is turned on and off, and the time intervals between switching it on and off and subsequent inclusion - equal.

Sources of information
1. Gas odorizer OG-10A. Catalog of technological equipment of gas distribution stations of gas pipelines. Moscow, 1997, pp. 86, 87.

 2. RF patent N 2125713 "Gas odorizer", authors N. N. Rosseev et al., IPC G 01 F 11/00, 13/00, priority dated 11/18/1997

 3. GOST 27.002-89. Reliability in technology. Basic concepts. Terms and Definitions.

Claims (1)

 A gas odorizer comprising a control unit, a working container, a metering cylinder equipped with a movable step piston dividing the metering cylinder into a metering chamber of variable volume connected to the tank, a command pressure chamber and an intermediate chamber, a throttle, and the command pressure chamber is connected via a controlled three-way electromagnetic a valve with a high pressure source and an intermediate chamber, and the working capacity, dosing and intermediate chambers are connected to the odorized gas pipeline m, characterized in that the movable piston device is made in the form of two coaxial pistons of larger and smaller diameters, mounted with the possibility of axial movement of one piston relative to the other, as well as joint movement of two pistons by an adjustable amount.

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