RU2784247C1 - Device for hydraulic impact damping - Google Patents

Abstract

FIELD: damping.

SUBSTANCE: operation of a device consists in that a flow of liquid or gas of a pipeline, at an output of branch pipe 7, in which pressure pulses act, is separated into N flows, and they are directed to channels having different delay because of different length. Next, pulses from channels, with energy reduced by N times (in each of them), are summed, at an input of branch pipe 8, coming in turn because of different time of passage through channels. A pulse front is extended, and undesired impact on the pipeline is reduced, respectively. Delay of each flow is calculated by the formula Tn=T1+delta*(n-1), where T1 is delay of the shortest flow, Tn is delay of n flow, delta is increment of flow delay, when increasing its number by one, n is number of flow.

EFFECT: smoothing a rate of rising a pressure pulse front and corresponding reduction in negative impact on a pipeline.

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Description

The invention relates to objects of heat supply, oil, gas, chemical, nuclear industries, as well as to aerospace engineering and can be used as a means of protecting pipelines from destruction as a result of the action of pulses and pressure pulsations in a liquid or gas accompanying a hydraulic shock that occurs when turning on, running and turning off pumps, opening and closing valves, gate valves and other devices.

Traditional devices for damping vibrations in pipelines are known, which consist in the fact that the flow of liquid or gas is divided into parts, and the flows discharged from the pipeline are led into damping chambers with elastic elements, in which the volume changes under the action of a pressure drop, due to the use of potential energy of pulses [12].

The disadvantage of this device is the limited frequency range of suppressed pressure pulses, depending on the rigidity of the elastic elements and the limited volume of the expansion chambers.

The closest in technical essence to the claimed invention (prototype) is a device that is implemented in the device for damping pressure pulses in main pipelines [3]. The method of dissipation of pressure impulses consists in the fact that the flows of liquid or gas of the main pipeline, in which pressure impulses act, are divided into parts, and the diverted parts are led through expansion chambers into a damping chamber, in which the flows are directed counter to the liquid or gas located in the chamber so that the pressure pulses change their density and pressure due to the potential energy of the pulses themselves and simultaneously twist the flows in opposite directions, slowing down the velocity of the liquid or gas due to the kinetic energy of the interaction of oncoming flows.

The advantage of the described device for damping pressure pulses is to increase the efficiency of damping pressure pulses due to the simultaneous dissipation of both potential and kinetic energies of the pulses themselves by changing the density, pressure and velocity of the oncoming flows of liquid or gas in the damping chamber.

The disadvantage of this device for suppressing pressure pulses is the low efficiency and the lack of an analytical tool for calculating the efficiency of the device.

The objective of the invention is to increase the efficiency of damping pressure fluctuations in pipelines by stretching the front of the pressure pulse in time.

The specified technical effect in the device for damping oscillations of pressure pulses is that the flow of liquid or gas of the pipeline is divided into parts in the inlet pipe, which are brought into channels of different lengths, where the flows move at the same speed, but at different times. When the channels in the outlet pipe are combined into a common flow, the front of the pressure pulse is stretched (smoothed) the more, the greater the number of channels used.

The different travel time of the pressure pulse in different channels is determined by the fact that all channels have different lengths, determined by the formula Ln=L1+delta*(n-1), where L1 is the length of the shortest channel (number 1), Ln is the length of channel number n , delta is the increment of the channel length when its number is increased by one, n is the channel number, N is the number of channels.

The essence of the proposed technical solution is illustrated by drawings, which show:

- figure 1 - Device dampening hydraulic shock,

- figure 2 - Smoothing the front of the pressure pulse.

1…6 - Channels of different lengths

7 - Inlet pipe

8 - Outlet

9 - Front pressure impulse in the inlet pipe

10 - Front impulse of pressure in the outlet pipe

11 - Front pressure pulse at the outlet of channel 1

16 - Front pressure pulse at the outlet of channel 6

The hydraulic shock damping device works as follows. In the steady state stationary mode, the flow of liquid or gas passing through the pipeline section has a constant pressure at the inlet of the nozzle 7 and at the outlet of the nozzle 8 of the device. In this case, a constant pressure is established in all channels 1…N.

The front of the resulting pressure pulse (water hammer) reaches the inputs of all channels simultaneously, but at the output of each channel it appears with a N-fold reduced energy (according to the number of channels N used) and with a delay depending on the channel length (on the channel number). As a result, the duration of the pulse front at the output of the device will be longer than at the input. The more channels used, the stronger will be the smoothing of the front of the pressure pulse and, accordingly, the less negative impact of the pressure pulse (water hammer) on the pipeline.

Thus, the proposed hydraulic shock damping device makes it possible to increase the efficiency of pressure pulse damping by stretching the front of the pressure pulse in time, similar to how an integrator works in electrical circuits.

Sources used

1. B.B. Nekrasov. Hydraulics and its application in aircraft. Publishing House "Engineering", M., 1967, p. 202.

2. RF patent No. 2386889, class. F16L, 55/04 for 2010

3. RF patent No. 2645860, class. F16L 55/04 for 2014 (prototype).

Claims (1)

A water hammer damping device consisting of branch pipes connected to the pipeline and interconnected by channels, characterized in that the channels connecting the pipes have different lengths, determined by the formula Ln=L1+delta*(n-1), where L1 is the length of the channel number 1 (the shortest), Ln - channel length number n, delta - channel length increment when its number is increased by one, n - channel number.

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