RU2805854C1 - Device for protecting floating dock from broken ice - Google Patents

Abstract

FIELD: shipbuilding; ship repair.

SUBSTANCE: devices for protecting a floating dock from broken ice. A device for protecting a floating dock from broken ice contains a source of compressed air and a perforated pipeline connected to it by a metal pipe, mounted on brackets and mounted along the guard contour below the level of the dock well deck. The perforated pipeline consists of perforated pipes with a diameter of 140 mm connected to each other by flanged connections with perforation holes with a diameter of 10 mm, located in a checkerboard pattern. The first row of holes is made at an angle of 90° up from the well deck, and the second row of holes is made with a 50 mm offset from the first row of holes away from the well deck. On the opposite side to the holes with a diameter of 10 mm in each pipe there are holes with a diameter of 25 mm with the ability to drain water when the floating dock surfaces. Inside each pipe with a diameter of 140 mm, an air supply pipe with a diameter of 57 mm is installed, secured by welding seams, along the entire length of which there are holes with a diameter of 10 mm, located at a distance of 100 mm relative to each other and looking down at an angle of 90° in relation to the well deck of the floating dock.

EFFECT: increasing the efficiency of removing ice from the deck of a floating dock.

1 cl, 4 dwg

Description

The invention relates to shipbuilding and ship repair, in particular to devices for protecting a floating dock from broken ice.

Used to float Dock 28. A pipe with a diameter of 57 was used, running along the entire length of the stern along the deck. The outlets ran the entire length of the pipe and looked down to the bottom of the deck. When the compressors were turned on, the air passed through the pipe and came out of the holes, hitting the deck and rising to the top. Air bubbles rose to the surface of the water, which drove away the ice floes as they sank. Efficiency was low and ice constantly fell onto the deck, making it difficult to repair ships. When cleaning the ice on the deck (the ice protection was constantly being broken by heavy equipment and ice). For maintenance, the ice had to be completely cut off. Protection for cleaning pipes from silt and dirt.

A device is known for protecting a floating dock from broken drifting ice, containing a source of compressed gas and a perforated pipeline connected to it, mounted on suspensions along the contour of the crinoline below the level of the dock slipway deck, characterized in that, in order to increase operational efficiency by shielding the ascending water-air flow , the pipeline hangers are made in the form of a solid vertical wall, and the perforated pipeline is mounted on the side of the wall external to the dock (SU 647179 A1, B63C 1/02, 02/15/1979).

The closest analogue of the claimed invention is a device for protecting a floating dock from broken ice, containing a source of compressed air and a perforated pipeline connected to it, mounted on suspensions and mounted along the crinoline contour below the level of the dock slipway deck, characterized in that, in order to increase efficiency ice retention, the perforated pipeline hangers are equipped with floats and mounted on the end of the dock by means of rings with the possibility of vertical movement relative to the end of the dock, and the connection of the perforated pipeline with a source of compressed air is made through a flexible hose (SU 662419 A1, B63C 1/02, 05/15/1979).

The disadvantages of the above technical solutions are low efficiency in driving ice away from the deck and ice getting onto the deck, which makes it difficult to repair ships.

The technical problem that the claimed invention is aimed at solving is the creation of a device for protecting a floating dock from broken ice that does not have the above-mentioned disadvantages.

The technical result of the claimed invention is to increase the efficiency of removing ice from the deck of a floating dock.

The technical result of the claimed invention is achieved in that a device for protecting a floating dock from broken ice, containing a source of compressed air and a perforated pipeline connected to it by a metal pipe, mounted on brackets and mounted along the crinoline contour below the level of the dock slipway deck, characterized in that the pipeline consists of perforated pipes with a diameter of 140 mm connected to each other by flange connections with perforation holes with a diameter of 10 mm, arranged in a checkerboard pattern, with the first row of holes made at an angle of 90° upward from the slipway deck, and the second row of holes made with an offset of 50 mm from the first row of holes away from the slipway deck, while on the opposite side in relation to the holes with a diameter of 10 mm of each pipe there are holes with a diameter of 25 mm with the ability to drain water when the floating dock surfaces, while a fixed pipe with a diameter of 140 mm is installed inside each pipe through welding seams, a pipe with a diameter of 57 mm for supplying air, along the entire length of which there are holes with a diameter of 10 mm, located at a distance of 100 mm relative to each other and oriented at an angle of 90° downward relative to the slipway deck of the floating dock.

The claimed invention is illustrated by drawings, where:

In fig. Figure 1 shows a section of the pipe.

In fig. Figure 2 shows a device for protecting a floating dock from broken ice.

In fig. Figure 3 shows a device for protecting a floating dock from broken ice with its fastening.

In fig. Figure 4 shows a graph of productivity depending on the number of holes on the outer pipe.

In fig. 1, 2 show a device for protecting a floating dock from broken ice, containing a source of compressed air and a perforated pipeline connected to it by a metal pipe with a diameter of 57 mm, mounted on brackets and mounted along the contour of the crinoline below the level of the dock slipway deck (Fig. 3). The pipeline consists of interconnected flange connections 5, which ensures easy maintenance of the device for protecting the floating dock from broken ice (ice protection), pipes 1 with a diameter of 140 mm with holes 3 with a diameter of 10 mm, arranged in a checkerboard pattern, with the first row of holes being made under at an angle of 90° upward from the slipway deck, and the second row of holes is made offset by 50 mm from the first row of holes away from the slipway deck. On the opposite side to the holes 3 with a diameter of 10 mm of each pipe there are holes 4 with a diameter of 25 mm with the ability to drain water when the floating dock surfaces. Inside each pipe 1 with a diameter of 140 mm there is a pipe 2 with a diameter of 57 mm, along the entire length of which there are holes (not shown in the drawings) with a diameter of 10 mm, located at a distance of 100 mm relative to each other and looking down at an angle of 90° with respect to to the slipway deck of the floating dock. In this case, the mentioned pipe 2 with a diameter of 57 mm is fixed in a pipe 1 with a diameter of 140 mm by means of welding seams.

An example of the invention.

We used pipe 1 with a diameter of 140 mm and a length of 2500 mm. We made 3 holes in the upper part of the pipe in a checkerboard pattern. The first (upper) row of holes 3 is at an angle of 90°, the second row of holes 3 is offset from the first row by 50 mm. The top row of holes is directed strictly 90° from the slipway deck upwards with a diameter of 10 mm. On the opposite side to the 10 mm holes, 4 holes with a diameter of 25 mm were cut to drain water when the floating dock surfaces. Pipe 1 with a diameter of 140 mm is installed inside a pipe 2 with a diameter of 57 mm, along the entire length of which holes are made every 100 mm, holes with a diameter of 50 mm, looking down at 90° in relation to the slipway-deck of the floating dock. Pipe 1 with a diameter of 57 mm is the main pipe for supplying air to a pipe with a diameter of 140 mm, which is a protective casing for a pipe with a diameter of 57 mm and a receiver.

The indicated hole size was selected to be 10 mm when testing ice protection; if the holes are made larger, then there is not enough air pressure and performance decreases.

When the PD-28 dock is immersed to the working depth, air under pressure rises to the surface and pushes the ice away from the ships' entry gates.

Calculation example:

To calculate the parameters of the gas flow of pipes nested inside each other with perforations, it is necessary to create a system of equations based on the critical formulas, which is done through the critical flow formulas.

m is the desired gas mass flow rate, kg/s;

C is the correction factor for the throughput of the nozzle (for simple perforation we take it as 1);

A is the cross-sectional area of the nozzle, m², calculated from its radius using the formula A=π·r², where π is a mathematical constant equal to 3.14, r is the radius of the nozzle, mm;

P - absolute gas pressure in front of the nozzle, Pa = N/m² = kg/(m s²);

k = cp/cv, and

cp - specific heat capacity at constant pressure, for air = 29.12 J mol-1 K-1,

cv - specific heat capacity at constant temperature, for air = 20.8 J mol-1 K-1,

that is, k = 1.4

M - molecular weight, kg/kmol. For compressed air = 28 kg/kmol;

Z is the compressibility coefficient at a certain pressure and temperature. For compressed air we take it as 1;

R - ideal gas constant = 8314.5 (N m)/(kmol K);

T is the gas temperature in front of the nozzle, K;

For the calculated system of two pipes nested inside each other, the relationship takes the following form:

A _int - cross-sectional area of the nozzle of the inner pipe, m², A _out - cross-sectional area of the nozzle of the outer pipe, m².

Since the same gas circulates in the two systems, the results of the radical expression differ only in the temperature parameter caused by the expansion (compression) of the gas. However, in real conditions, it is advisable not to take this parameter into account, considering that due to natural heat exchange through the walls of the inner pipe, the gas temperatures are equalized. With this assumption, it is advisable to designate the radical expression as coefficient H.

By transforming these expressions we obtain a system of equations:

Manual recalculation of this system of equations to select parameters is impractical in practice. To effectively solve the problem, it is most convenient to use the MathLab software product.

function[A1]=squareA1(R1,Q1)% Function for calculating the area of holes in the inner pipe

A1=pi*R1^2*Q1; % Q1 - number of holes R1 - radius of each in meters

function[A1]=squareA1(R1,Q1)% Function for calculating the area of holes in the inner pipe

A1=pi*R1^2*Q1; % Q1 - number of holes R1 - radius of each in meters

function[V,Ppr]=preasure(A1,A2,P,T)

C=1; % - correction factor for nozzle throughput (for simple perforation we take it as 1)

%P - absolute gas pressure in front of the nozzle, Pa = N/m² = kg/(m⋅s²)

k=1.4; %cp/cv, where cp is the specific heat capacity at constant pressure, for air = 29.12 J•mol-1⋅K-1

%wherein cv is the specific heat at constant temperature, for air = 20.8 J⋅mol-1⋅K-1, that is, k = 1.4

M=28; % - molecular weight, kg/kmol. For compressed air = 28 kg/kmol

Z=1; % - compressibility coefficient at a certain pressure and temperature. For compressed air we take it as 1

R=8314.5; % - ideal gas constant = 8314.5 (N⋅m)/(kmol⋅K)

% T - gas temperature in front of the nozzle, K

H=sqrt(((k*M)/(Z*R*T)*(2/(k+1))^((k+1)/(k-1)))); % - intermediate coefficient

Ppr=(A1.*P)/(A1+A2); % - Calculation of intermediate pressure between pipes

V=C.*A1.*P.*H.*(1-(A1./(A2+A1)))ω*3600ω/1.2; % Volume flow calculation. Coefficient 1.2 converts mass flow to volume flow

Specific calculation example:

As an example of a calculation, a practical problem of adjusting the flow parameters of an already installed ice protection system of a floating dock is given. Protected area 40 m

The system parameters are as follows:

Inner pipe

∅57 mm;

Perforation - ∅10 mm;

Perforation pitch - 100 mm;

Outer pipe

∅140 mm

Perforation - ∅10 mm;

Segment design, 2.5 m each segment. The arrangement of holes is staggered, 12 pcs. on each side per segment.

The system has been installed. It has proven its efficiency. However, it had too much power. There was a need to reduce parameters by reducing the number or diameter of holes.

Under current conditions the parameters are as follows:

V - 3.4468 m ³ /hour - volumetric flow rate of each side

Ppr - 4.081 kgf/cm. - intermediate pressure in the overpass.

When the above program is ready, introduce the initial conditions as follows:

>>A1=squareA1(0.01,400)

>> A2=squareA2(0.01,1:1:384);

>> V=preasure(A1,A2,8,300);

>>plot(V)

>> title('Dependence of performance on the number of holes in the outer pipe')

>> xlabel('Number of holes')

>> ylabel({'Air flow';'in m^3/hour'})

leads to the result shown in FIG. 4. This dependence reflects the consumption of each of the protected sides depending on the number of holes. This allows you to adjust the flow rate to the existing performance parameters of air compressors.

Claims (1)

A device for protecting a floating dock from broken ice, containing a source of compressed air and a perforated pipeline connected to it by a metal pipe, mounted on brackets and mounted along the contour of the crinoline below the level of the dock slipway deck, characterized in that the pipeline consists of perforated pipes interconnected by flange connections pipes with a diameter of 140 mm with perforation holes with a diameter of 10 mm, arranged in a checkerboard pattern, with the first row of holes made at an angle of 90° upward from the slipway deck, and the second row of holes made with an offset of 50 mm from the first row of holes away from the slipway - deck, while on the opposite side in relation to the holes with a diameter of 10 mm of each pipe there are holes with a diameter of 25 mm with the ability to drain water when the floating dock ascends, while inside each pipe with a diameter of 140 mm, a pipe with a diameter of 57 mm is installed, secured by welding seams, for supply air, along the entire length of which there are holes with a diameter of 10 mm, located at a distance of 100 mm relative to each other and oriented at an angle of 90° downward relative to the slipway deck of the floating dock.