A ductile iron pipe pressure testing device and pressure testing method

Abstract

The present invention discloses a ductile iron pipe pressure test device and a pressure test method, and belongs to the technical field of pipeline pressure test. Aiming at the problems in the prior art that the pressure test of ductile iron pipes requires the construction of a backrest, the pressure test device is complicated, and the pressure test process is inefficient, the present invention provides a ductile iron pipe pressure test device, comprising a ductile iron pipe, one end of which is provided with a water supply mechanism and a pressure measuring mechanism, the other end of the ductile iron pipe is connected to one end of a steel pipe, the other end of the steel pipe is provided with a water supply mechanism and a pressure measuring mechanism, a plugging plate is provided inside the steel pipe, an inlet pipe is provided outside between the front and rear sections of the steel pipe, a pressure measuring mechanism is provided on the inlet pipe, and a water supply valve and an exhaust valve are provided on both sides of the pressure measuring mechanism. The pressure test device has a simple structure and is easy to install; and the pressure test method described in the present invention does not require the construction of a backrest on the ductile iron pipe, and the ductile iron pipe is subjected to a water pressure test through the steel pipe and the plugging plate inside the steel pipe, which is easy to operate, saves construction process, and accelerates construction efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline pressure testing, and more specifically, relates to a ductile iron pipe pressure testing device and a pressure testing method. Background Art

[0002] Pipeline pressure testing is a particularly important step in pipeline construction. According to the design and specification requirements, after the pipeline is installed, check whether the joints of the pressure section pipes are sealed and whether the pressure meets the operating requirements. In the conventional pressure testing method for large-diameter ductile iron pipes, in order to ensure that the pipeline is not disturbed, the pressure on the plugs at both ends must be offset by the concrete backrest + original dense soil while covering the soil. This method has high requirements on the back soil quality, and the concrete backrest must reach a certain strength before the pressure test can be carried out; the process is relatively complicated and the construction is cumbersome, which consumes time and manpower.

[0003] Corresponding improvements have also been made to address the above problems, such as Chinese patent application number CN200410013979.2, published on December 29, 2004. The patent discloses a large-diameter pipeline construction intermediate pressure test technology and device. The pressure test device consists of a steel pipe, a steel partition welded inside the steel pipe, an H-shaped bypass pipe, and a water injection pipe, a bypass valve, an exhaust valve, and a pressure gauge installed on the bypass pipe. The device is connected to the pressure test pipeline through a pipe joint. After water injection, the leakage is checked, and then the steel partition and bypass pipe are removed by draining the water and then sealing and welding. The present invention overcomes the drawback that long-distance pipelines must be constructed intermittently due to pressure testing in the past, and speeds up the progress of engineering construction. The disadvantage of this patent is that it is not easy to control the pressure on both sides to be the same when pressurizing both sides at the same time, and more manpower is required to increase costs.

[0004] Another example is Chinese patent application No. 201310453054.9, published on December 25, 2013. The patent discloses a pressure testing method and device for water pipelines in hilly areas. The pressure test method includes: (1) at least one pressure test section is set on the water pipeline, each pressure test section is equipped with a plugging plate and an expansion joint I to separate the pressure test section into an upstream and downstream pressure test section, and a connecting pipe is set at the bottom of the upstream and downstream pressure test sections of each pressure test section, and two branches are connected in parallel between the two connecting pipes, one of which is connected with a valve and an expansion joint II, and the other is connected with a pressure pump; each pressure test section is provided with a pressure test pier with a U-shaped or circular concrete structure side wall, and the concrete structure side wall of the pressure test pier is rigidly connected to the upstream and downstream pressure test sections of the pressure test section, respectively, and the plugging plate, the pressure pump, etc. are located in the cavity of the pressure test pier; (2) the upstream pressure test section and / or the downstream pressure test section of at least one pressure test section are filled with water separately or simultaneously for pressure test; (3) after the pressure test is completed, the plugging plate is replaced with a through-hole flange with a through hole to connect with the water pipeline. The disadvantage of this patent is that when a single pressure test is performed, the pressure easily causes the two sections to collapse due to the pressure difference, which has certain safety hazards. Summary of the invention

[0005] 1. Problem to be solved

[0006] In view of the problems in the prior art that the pressure test of ductile iron pipes requires the construction of a backrest, the pressure test device is complicated, and the pressure test process is inefficient, the present invention provides a ductile iron pipe pressure test device and a pressure test method. The pressure test device has a simple structure and is easy to install; and the pressure test method described in the present invention does not require the construction of a backrest on the ductile iron pipe, and the ductile iron pipe is subjected to a water pressure test through a steel pipe and a plugging plate inside the steel pipe, which is easy to operate, saves construction process, and speeds up construction efficiency.

[0007] 2. Technical solution

[0008] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0009] A ductile iron pipe pressure test device comprises a ductile iron pipe, one end of which is provided with a water supply mechanism and a pressure measuring mechanism, the other end of the ductile iron pipe is connected to one end of a steel pipe, the other end of the steel pipe is provided with a water supply mechanism and a pressure measuring mechanism, a plugging plate for dividing the steel pipe into two sections of a steel pipe body is provided inside the steel pipe, a water inlet pipe is provided outside between the two sections of the steel pipe, a pressure measuring mechanism is provided on the water inlet pipe, and a water supply valve and an exhaust valve are provided on both sides of the pressure measuring mechanism. The device has a simple structure, is easy to install and disassemble, simplifies the pressure test procedure, and saves water resources.

[0010] Furthermore, the water supply mechanism includes a water inlet box, a water inlet main pipe connected to the water inlet box, two water inlet branches connected to the water inlet main pipe, a water inlet main valve is arranged on the water inlet main pipe, a pressure test pump and a pressure boosting valve are arranged on one water inlet branch, and a water inlet valve is arranged on the other water inlet branch. The division of labor is clear and the operation efficiency is improved.

[0011] Furthermore, the water inlet manifolds are all provided with check valves to improve the safety performance of the entire water inlet process and prevent water backflow.

[0012] Furthermore, both the ductile iron pipe and the steel pipe are provided with a drainage pipe, a drainage valve is provided on the drainage pipe, and the drainage pipe is connected to the water supply mechanism, so as to recycle and utilize water resources and avoid the waste of water resources.

[0013] Furthermore, the drainage pipe is connected to the ductile iron pipe and the steel pipe through flanges, so that the installation and replacement of the drainage pipe are more convenient, and the flange connection relationship is stable.

[0014] Furthermore, the pressure measuring mechanism on the water inlet pipe is a pressure gauge II, and the pressure gauge II is arranged on the water inlet pipe through a bracket. The structure is simple and the measurement result is relatively accurate.

[0015] Furthermore, it also includes an alarm, which is electrically connected to the pressure gauge II. The timeliness of the entire water pressure test process is improved, and when the pressure exceeds the preset value of the pressure gauge II, the alarm works to remind the staff in time.

[0016] Furthermore, the steel pipe is provided with a manhole for operators to enter and exit the steel pipe, so as to facilitate the installation and removal of the blocking plate.

[0017] A pressure testing method using the ductile iron pipe pressure testing device as described in any one of the above, comprising the following steps:

[0018] 1. Connect one end of the ductile iron pipe to the steel pipe and set a plug inside the steel pipe;

[0019] 2. Open the two water supply valves and exhaust valve on the water inlet pipe, and fill the ductile iron pipe and steel pipe with water through the water inlet mechanism at one end of the ductile iron pipe or the water inlet mechanism at one end of the steel pipe;

[0020] 3. When the ductile iron pipe and the steel pipe are filled with water, continue to inject water through the water inlet mechanism to pressurize the ductile iron pipe and the steel pipe. After the pressure is completed, close the water supply valve close to the ductile iron pipe;

[0021] 4. Conduct a water pressure test on a section of steel pipe away from the ductile iron pipe;

[0022] 5. After the water pressure test of the section of the steel pipe body away from the ductile iron pipe is completed, open the water supply valve close to the ductile iron pipe. At this time, the ductile iron pipe and the steel pipe body connected to the ductile iron pipe form a common pipeline. When the pressure of the pipeline detected by the pressure measuring mechanism and the pressure of the section of the steel pipe body away from the ductile iron pipe reach a pressure balance, close the water supply valve away from the ductile iron pipe;

[0023] 6. Conduct a water pressure test on a section of steel pipe close to the ductile iron pipe;

[0024] 7. After the pressure test of the ductile iron pipe is completed, the operator will remove the plugging plate.

[0025] The method is easy to operate, which changes the previous situation where the backrest needs to be made and constructed separately, compresses and optimizes the construction process, not only saves manpower, material and financial resources, but also speeds up the pressure test progress. Under the premise of ensuring quality, the ductile iron pipe 11 pressure test work can be successfully completed.

[0026] Furthermore, the strength of the pressure applied to the ductile iron pipe and the steel pipe in step 3 is half of the test pressure strength. It is convenient to control and easy to operate.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention utilizes one end of a ductile iron pipe that needs to be pressure tested to connect a steel pipe, and a plugging plate is arranged inside the steel pipe to divide the steel pipe into two sections. The arrangement of the steel pipe eliminates the need for separate pressure testing and backrest production in the traditional water pressure test of the ductile iron pipe, thereby simplifying the construction process and reducing resource investment. At the same time, a water inlet pipe is arranged between the two sections of the steel pipe body, and two water supply valves and an exhaust valve are arranged on the water inlet pipe. The two sections of the steel pipe body are pressure tested in sections, which simplifies the pressure test procedure, saves water resources, and speeds up the overall construction progress.

[0030] (2) The water supply mechanism of the present invention is provided with two water inlet branches, and one water inlet branch is provided with a pressure test pump and a pressure boosting valve for pressure test operation, and the other water inlet branch is provided with a water inlet valve for pipeline water injection operation in the early stage of pressure test. Since the early stage of pipeline water injection operation does not require the use of a pressure test pump and a pressure boosting valve, only ordinary water inlet is required. The provision of two water inlet branches avoids operator errors, improves the accuracy of division of labor, and ensures the smooth progress of the entire water pressure test process;

[0031] (3) In the present invention, a check valve is provided on each water inlet branch. The setting of the check valve can effectively avoid the phenomenon of backflow when the water flow is transported into the pipeline, thereby ensuring the safety performance of the water inlet process; and the pressure test pump is a pneumatic pump, which has a simple structure and a small size, thereby reducing the load on the water inlet branch;

[0032] (4) The present invention provides drainage pipes on both the ductile iron pipe and the steel pipe, and drainage valves are provided on the drainage pipes to facilitate the discharge of water in the ductile iron pipe and the steel pipe; and the drainage pipes are connected to the water supply mechanism, so that the water resources used in the entire hydraulic pressure test can be recycled to avoid waste of water resources;

[0033] (5) The pressure measuring mechanism on the water inlet pipe of the present invention is a pressure gauge II. The pressure gauge II has a simple structure, accurate measurement effect, and is convenient for operators to read the pressure value intuitively and quickly; the pressure gauge II is arranged on the water inlet pipe through a bracket, and the fixation of the pressure gauge II is strengthened, so that the pressure measurement result is more accurate and the measurement error of the steel pipe is reduced; and the pressure gauge II is electrically connected to the alarm. When the pressure value exceeds the preset pressure value, the alarm works to remind the staff in time;

[0034] (6) The plugging plate of the present invention is arranged at the middle section of the steel pipe. Since the steel pipe bodies on both sides of the plugging plate need to be pressurized before the water pressure test, the plugging plate arranged at the middle section of the steel pipe makes it easier to control the pressure balance of the steel pipe bodies on both sides of the plugging plate during the pressurization. At the same time, the welding of the plugging plate and the steel pipe ensures the stability of the connection between the plugging plate and the steel pipe. A manhole for operators to enter and exit is arranged on the steel pipe, which facilitates the installation and removal of the plugging plate and improves work efficiency.

[0035] (7) The pressure testing method of the present invention first fills the ductile iron pipe and the steel pipe with water and applies pressure, so that the ductile iron pipe and the steel pipe have a certain pressure before the water pressure test. On the one hand, this prevents the two sections of the steel pipe from being easily broken due to the large pressure difference when the water pressure test is performed on one section of the steel pipe, thereby ensuring the safety performance of the entire pressure testing process. On the other hand, since the steel pipe itself has a certain pressure, it is only necessary to increase the pressure step by step on this basis, which saves the pressure testing time and also saves water resources. The entire pressure testing method for the ductile iron pipe is simple to operate, efficient and cost-effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the process of the present invention;

[0037] Figure 2 It is a structural schematic diagram of the present invention.

[0038] In the figure: 1. Main water inlet valve; 2. Pressure test pump; 3. Pressurizing valve; 4. Water inlet valve; 5. Drain valve; 6. Pressure gauge I; 7. Pressure gauge II; 8. Water supply valve I; 9. Water supply valve II; 10. Exhaust valve; 11. Ductile iron pipe; 12. Steel pipe; 13. Blocking plate. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific embodiments.

[0040] Example 1

[0041] like Figure 1 and Figure 2As shown, a ductile iron pipe pressure test device comprises a ductile iron pipe 11, which is a pipe to be tested in a water pressure test; one end of the ductile iron pipe 11 is provided with a water supply mechanism and a pressure measuring mechanism, and the other end of the ductile iron pipe 11 is connected to one end of a steel pipe 12, and the other end of the steel pipe 12 is provided with a water supply mechanism and a pressure measuring mechanism; specifically, the water supply mechanisms on the ductile iron pipe 11 and the steel pipe 12 are mechanisms for supplying water to the entire water pressure test, and specifically, the water supply mechanism comprises a water inlet tank , a water inlet main pipe connected to the water inlet tank, two water inlet branches connected to the water inlet main pipe, a water inlet main pipe is provided with a water inlet valve 1, a pressure test pump 2 and a pressure boosting valve 3 are provided on one water inlet branch, and a water inlet valve 4 is provided on the other water inlet branch. One end of the two water inlet branches is connected to the water inlet main pipe, and the other end is connected to the ductile iron pipe 11 or the steel pipe 12; when the ductile iron pipe 11 and the steel pipe 12 are filled with water in the early stage of the water pressure test, the water inlet main valve 1 and the water inlet valve 4 are opened, and the test is carried out. The pressure pump 2 and the pressure boosting valve 3 are in a closed state, and water flows into the two pipes through the water inlet splitter 4 so that the two pipes are filled with water; when it is necessary to perform a pressure-boosting operation on the two pipes, the water inlet splitter 4 is closed, the water inlet main valve 1, the pressure test pump 2 and the pressure boosting valve 3 are opened, and the water flows into the two pipes through the pressure test pump 2 and the pressure boosting valve 3 to perform a pressure-boosting operation on the two pipes; setting up two water inlet pipelines makes the entire operation process clearly divided, avoids the pressure test pump 2 and the pressure boosting valve 3 from being used unnecessarily and wasting resources, and reduces operator errors; specifically, the pressure measuring mechanism is a pressure gauge I6, which has a simple structure, accurate measurement effect and can facilitate operators to obtain readings intuitively and quickly; the two pressure gauges I6 are respectively vertically arranged on the ductile iron pipe 11 and the steel pipe 12 through brackets, so that the measurement structure is more accurate; other water supply mechanisms and pressure measuring mechanisms for measuring pressure that can provide water resources for the water pressure test of the ductile iron pipe 11 and the steel pipe 12 can be used in the present invention;

[0042] A plugging plate 13 is arranged inside the steel pipe 12, which divides the steel pipe 12 into two sections, front and rear sections of the steel pipe body. Specifically, the plugging plate 13 is welded inside the steel pipe 12. The welding connection is stable and can effectively prevent the plugging plate 13 from separating from the steel pipe 12 under the impact of high-pressure water flow; the setting of the plugging plate 13 divides the steel pipe 12 into a front half steel pipe body connected to the ductile iron pipe 11 and a rear half steel pipe body connected to the water supply mechanism; an inlet pipe is arranged outside between the front and rear sections of the steel pipe body, that is, one end of the inlet pipe is connected to the front half steel pipe body, and the other end is connected to the rear half steel pipe body; a pressure measuring mechanism is arranged on the water inlet pipe, and a water supply valve and an exhaust valve 10 are arranged on both sides of the pressure measuring mechanism; specifically, the water supply valve is divided into a water supply valve I8 and a water supply valve II9, which are respectively arranged on both sides of the pressure measuring mechanism, and the water supply valve I8 is close to the ductile iron pipe 11. The cast iron pipe 11 is arranged on the water inlet pipe corresponding to the front half of the steel pipe body, and the water supply valve II9 is ​​arranged on the water inlet pipe corresponding to the rear half of the steel pipe body; the pressure measuring mechanism on the water inlet pipe is a pressure gauge II7, which has a simple structure, accurate measurement effect, and is convenient for the operator to read the pressure value intuitively and quickly; the pressure gauge II7 is arranged vertically in the water inlet pipe, so that the measurement result is more accurate; the operator realizes the segmented water pressure test of the two different sections of the steel pipe body by adjusting the opening or closing of the two water supply valves, that is, finally completes the water pressure test of the ductile iron pipe 11, and the setting of the exhaust valve 10 is helpful to discharge the air in the ductile iron pipe 11 and the steel pipe 12, and secondly, it enables the operator to intuitively detect that the two pipes are filled with water, so that the whole operation has a higher safety performance.

[0043] The ductile iron pipe pressure test device described in the present invention uses the steel pipe 12 connected to the ductile iron pipe 11 as a backrest, thereby eliminating the need to construct a backrest to offset the pressure when the traditional ductile iron pipe is subjected to a water pressure test, thereby simplifying the construction process and saving material and labor costs; and the setting of the plugging plate 13 divides the steel pipe 12 into two sections of steel pipe bodies. When one section of the steel pipe body is subjected to a pressure test, the other section of the steel pipe body acts as a backrest to provide support, thereby avoiding certain safety accidents caused by the large pressure difference on both sides of the plugging plate 13 falling off from the steel pipe 12 during the water pressure test; in the past, when the ductile iron pipe 11 was subjected to a water pressure test, the efficiency of the entire water pressure test was slow due to the separate production and construction of the backrest, and a large amount of manpower and material resources were consumed to install and disassemble the traditional backrest; the operation of segmented pressure testing is performed by the pressure measuring mechanism and the water supply valve on the water inlet pipe, which, on the one hand, simplifies the pressure testing procedure and saves water resources; and on the other hand, speeds up the overall construction progress; the entire device has a simple structure, is easy to install and disassemble, and has a high use value.

[0044] Example 2

[0045] Basically the same as Example 1, preferably, a check valve is provided on the water inlet branch, and the setting of the check valve can effectively prevent the reverse flow of water during water injection or pressure boosting operation, thereby ensuring the safety performance of the entire pressure test process; further, the pressure test pump 2 is a pneumatic pump, which has a simple structure and a small size, reduces the load on the water inlet branch, and increases the service life of the water inlet branch; more specifically, a drainage pipe is provided on the ductile iron pipe 11 and the steel pipe 12, and a drainage valve 5 is provided on the drainage pipe, and the drainage pipe is connected to the water supply mechanism; it is convenient for the ductile iron pipe to 11 and the steel pipe 12 are discharged; and the drain valve 12 is connected to the water supply mechanism through a pipeline, so that the water resources can be recycled and reused, avoiding the waste of water resources and saving costs; in this embodiment, the drain valve 5 can be connected to the water inlet tank in the water supply mechanism described in Example 1 through a pipeline to store and utilize the recovered water resources; further, the drain pipe is connected to the ductile iron pipe 11 and the steel pipe 12 through a flange, and a detachable installation is performed through the flange, which is convenient for the installation and replacement of the drain pipe, and the flange connection makes the connection relationship stable.

[0046] Example 3

[0047] Basically the same as Example 2, preferably, the baffle 13 is arranged in the middle section of the steel pipe 12, that is, in the middle position of the steel pipe 12. Because the steel pipe bodies on both sides of the baffle 13 need to be pressurized before the water pressure test, the baffle 13 arranged in the middle section of the steel pipe 12 makes it easier to control the balance of the pressure of the steel pipe bodies on both sides during the pressure test; the pressure gauge II7 corresponds to the position of the baffle 13, so that the pressure gauge II7 can measure the pressure of the front and rear sections of the steel pipe body more accurately; further, it also includes an alarm, which is electrically connected to the pressure gauge II7. When the value on the pressure gauge II7 exceeds the preset value, the signal is transmitted to the alarm. The alarm works to remind the staff in time, thereby improving the safety performance of the whole process. The preset value is generally set according to the specific pressure test conditions of the ductile iron pipe 11 on site; further, a manhole for operators to enter and exit the steel pipe 12 is provided on the steel pipe 12, which is convenient for operators to install and disassemble the baffle 13.

[0048] Example 4

[0049] A pressure testing method using the ductile iron pipe pressure testing device described in any one of the above embodiments 1-3 comprises the following steps:

[0050] 1. Connect one end of the ductile iron pipe 11 to the steel pipe 12, and set a plugging plate 13 inside the steel pipe 12;

[0051] 2. Open the two water supply valves and the exhaust valve 10 on the water inlet pipe, and fill the ductile iron pipe 11 and the steel pipe 12 with water through the water inlet mechanism at one end of the ductile iron pipe 11 or the water inlet mechanism at one end of the steel pipe 12; specifically, in this embodiment, water resources are transported by opening the water inlet mechanism at one end of the steel pipe 12, and the water inlet mechanism is as described in Example 1; open the water inlet main valve 1 and the water inlet branch valve 4, close the pressure test pump 2 and the pressure boosting valve 3, and a part of the water flows through the water inlet branch into the water connected to the water inlet branch. In the rear half of the steel pipe body, the water flow cannot directly enter the front half of the steel pipe body connected to the ductile iron pipe 11 from the rear half of the steel pipe body due to the presence of the blocking plate 13, so another part of the water flows into the front half of the steel pipe body and the ductile iron pipe 11 through the water inlet pipe; at this time, the water supply valve I8 and the water supply valve II9 and the exhaust valve 10 on the water inlet pipe are opened. When the exhaust valve 10 overflows the water flow, it indicates that the pipe is full of water, that is, the water injection into the ductile iron pipe 11 and the steel pipe 12 is stopped;

[0052] 3. When the ductile iron pipe 11 and the steel pipe 12 are filled with water, continue to feed water through the water inlet mechanism to pressurize the ductile iron pipe 11 and the steel pipe 12. After the pressure is completed, close the water supply valve close to the ductile iron pipe 11; specifically, when the ductile iron pipe 11 and the steel pipe 12 are filled with water, close the water inlet valve 4, open the water inlet main valve 1, the pressure test pump 2 and the pressure valve 3 to inject water and pressurize the steel pipe 12 and the ductile iron pipe 11. The pressure value can be determined according to the specific situation, so that the ductile iron pipe 11 and the steel pipe 12 have a certain pressure before the water pressure test; such a setting can avoid the need to perform water pressure test on the front half of the steel pipe body or the rear half of the steel pipe body separately. During the test, the steel pipe bodies on both sides of the plugging plate 13 are prone to collapse and breakage of the plugging plate 13 and the steel pipe 12 due to the large water pressure difference, which ensures the safety performance of the whole process; after the pressure test is completed, close the water inlet main valve 1, the pressure test pump 2, the pressure boosting valve 3 and the water supply valve II9 close to the ductile iron pipe 11; prepare for the next step of the water pressure test on the rear half of the steel pipe body connected to the pressure test mechanism; preferably, the intensity of the water injection pressure test on the ductile iron pipe 11 and the steel pipe 12 is half of the pressure test intensity; for easy operation and control, when the value displayed on the pressure gauge I6 on the ductile iron pipe 11 and the steel pipe 12 is half of the pressure test pressure value, stop further water injection;

[0053] 4. Perform a water pressure test on a section of the steel pipe body away from the ductile iron pipe 11; specifically, the water pressure test is performed as follows: one end of the section of the steel pipe body is connected to the water supply mechanism, which is the rear half of the steel pipe body, close the water inlet branch valve 4, open the water inlet main valve 1, the pressure test pump 2 and the pressure boosting valve 3, and the water flows into the rear half of the steel pipe body through the water inlet branch valve. Since the water supply valve II9 is ​​in a closed state, the water will not flow into the front half of the steel pipe body connected to the ductile iron pipe 11; slowly increase the water flow pressure to the test pressure, if there is a pressure drop during this period Water can be injected to replenish pressure, but the pressure should not be higher than the test pressure; check whether there is any leakage or damage at the pipe joints, accessories, etc.; if there is leakage or damage, the pressure test should be stopped in time, the cause should be found out and the corresponding measures should be taken before re-testing the pressure, and water injection should be stopped to stabilize for 15 minutes. After 15 minutes, there is no pressure drop in the steel pipe body. The test pressure is reduced to the working pressure and maintained at a constant pressure for 30 minutes. Perform an appearance inspection. If there is no leakage, the water pressure test of the steel pipe body of this section is qualified; during this period, the pressure can be observed and adjusted through the pressure gauge I6 set on the steel pipe 12;

[0054] 5. After the water pressure test of a section of the steel pipe body away from the ductile iron pipe 11 is completed, the water supply valve close to the ductile iron pipe 11 is opened. At this time, the ductile iron pipe 11 and the steel pipe body connected to the ductile iron pipe 11 form a common pipeline. When the pressure measuring mechanism detects that the pressure of the pipeline and the pressure of a section of the steel pipe body away from the ductile iron pipe 11 reach a pressure balance, the water supply valve away from the ductile iron pipe 11 is closed; specifically, when the water pressure test of the rear half of the steel pipe body is completed, the water supply valve II9 previously closed on the water inlet pipeline is opened, so that the water flow in the rear half of the steel pipe body enters the front half of the steel pipe body and the ductile iron pipe 11. At this time, the pressure gauge II7 on the water inlet pipeline is observed. When the pointer on the pressure gauge II7 is at the half position of the dial, it means that the pipeline composed of the ductile iron pipe 11 and the front half of the steel pipe body reaches a pressure balance with the pressure of the rear half of the steel pipe body. At this time, the water supply valve I8 is closed to prepare for the next step of the water pressure test on the ductile iron pipe 11;

[0055] 6. Perform a water pressure test on the ductile iron pipe 11; specifically, the water pressure test is performed as follows: at this time, the water supply mechanism at one end of the ductile iron pipe 11 works, the water inlet valve 4 is closed, the main water inlet valve 1, the pressure test pump 2 and the pressure boosting valve 3 are opened, and the water flows through the water inlet branch into the front half of the steel pipe body connected to the ductile iron pipe 11. Since the water supply valve I8 is in a closed state, the water will not enter the rear half of the steel pipe body; the water flow pressure is slowly increased to the test pressure. If there is a pressure drop during this period, water can be injected to replenish the pressure, but it must not be higher than the test pressure; check whether there is any leakage or damage at the pipeline interface, accessories, etc.; if there is any leakage or damage, the pressure test should be stopped in time, the cause should be found out and the corresponding measures should be taken before re-testing the pressure, and the water injection and pressure replenishment should be stopped, and it should be stabilized for 15 minutes. After 15 minutes, the pressure drop of the ductile iron pipe 11 should not exceed 0.03MPa, the test pressure is brought to the working pressure and maintained at a constant pressure for 30 minutes, and an appearance inspection is performed. If there is no water leakage, the ductile iron pipe 11 is qualified in the water pressure test; during the period, the pressure can be observed and adjusted by the pressure gauge I6 set on the ductile iron pipe 11; when the ductile iron pipe 11 is subjected to a water pressure test, the front half of the steel pipe body has pressure due to the operation of step 2 and step 5, and the pressure is gradually increased on the basis of the pressure, which saves the pressure test time and construction cost, and also avoids the waste of water resources to a certain extent; and the rear half of the steel pipe body also has pressure. When the ductile iron pipe 11 is subjected to a water pressure test, the rear half of the steel pipe body acts as a backrest, so that the two sides of the plugging plate 13 will not collapse and separate from the steel pipe 12 due to the large pressure difference;

[0056] 7. After the pressure test of the ductile iron pipe 11 is completed, the operator removes the plugging plate 13 and drains the water in the ductile iron pipe 11 and the steel pipe 12.

[0057] The pressure test method of the present invention compresses and optimizes the construction process, which not only saves manpower, material resources and financial resources, but also speeds up the pressure test progress, and can satisfactorily complete the pressure test of the ductile iron pipe 11 under the premise of ensuring quality; by first filling the ductile iron pipe 11 and the steel pipe 12 with water and applying pressure, the inside of the ductile iron pipe 11 and the steel pipe 12 has a certain pressure before the water pressure test, and the steel pipe 12 acts as a backrest, thereby preventing the two sides of the plugging plate 13 from easily collapsing due to the large pressure difference when the water pressure test is performed on the steel pipe 12 or the ductile iron pipe 11 alone, thereby ensuring the safety performance of the entire pressure test process, and changing the traditional pressure test of the ductile iron pipe 11. During the water pressure test, the backrest needs to be made and constructed separately, which saves construction procedures and improves work efficiency. On the other hand, since the ductile iron pipe 11 and the steel pipe 12 have a certain pressure themselves, it is only necessary to increase the pressure step by step on this basis, which saves the pressure test time and also saves water resources. Most of the existing technologies use pressure on both ends of the ductile iron pipe 11 at the same time, which increases the number of operators. Secondly, due to the influence of various factors, it is not convenient to control the two ends to be pressurized to the test pressure at the same time, and the simultaneous water inflow at both ends to reach the test pressure will consume a lot of water resources, and the overall cost is high. The entire pressure test method for the ductile iron pipe 11 of the present invention is simple to operate, efficient and cost-saving.

[0058] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A pressure testing method using a ductile iron pipe pressure testing device, the ductile iron pipe pressure testing device comprising a ductile iron pipe (11), one end of the ductile iron pipe (11) being provided with a water supply mechanism and a pressure measuring mechanism, and the other end being connected to one end of a steel pipe (12), the other end of the steel pipe (12) being provided with a water supply mechanism and a pressure measuring mechanism; a blocking plate (13) is provided inside the steel pipe (12) for dividing the steel pipe (12) into two front and rear sections of a steel pipe body, an inlet pipe is provided outside between the front and rear sections of the steel pipe body, the inlet pipe is provided with a pressure measuring mechanism, and both sides of the pressure measuring mechanism are provided with a water supply valve and an exhaust valve (10); the water supply mechanism comprises a water inlet box, a water inlet main pipe connected to the water inlet box, two water inlet branches connected to the water inlet main pipe, a water inlet main valve (1) is provided on the water inlet main pipe, a pressure test pump (2) and a pressure boosting valve (3) are provided on one water inlet branch, and a water inlet valve (4) is provided on the other water inlet branch; The pressure testing method comprises the following steps:

1. Connecting one end of the ductile iron pipe (11) to the steel pipe (12), and providing a blocking plate (13) inside the steel pipe (12); 2. Open the two water supply valves and the exhaust valve (10) on the water inlet pipe, and fill the ductile iron pipe (11) and the steel pipe (12) with water through the water inlet mechanism at one end of the ductile iron pipe (11) or the water inlet mechanism at one end of the steel pipe (12); 3. When the ductile iron pipe (11) and the steel pipe (12) are filled with water, water is continuously introduced through the water inlet mechanism to pressurize the ductile iron pipe (11) and the steel pipe (12). After the pressurization is completed, the water supply valve close to the ductile iron pipe (11) is closed; 4. performing a water pressure test on a section of the steel pipe body away from the ductile iron pipe (11); 5. After the water pressure test of the section of the steel pipe body away from the ductile iron pipe (11) is completed, the water supply valve close to the ductile iron pipe (11) is opened. At this time, the ductile iron pipe (11) and the steel pipe body connected to the ductile iron pipe (11) form a pipeline. When the pressure of the pipeline and the pressure of the section of the steel pipe body away from the ductile iron pipe (11) detected by the pressure measuring mechanism reach a pressure balance, the water supply valve away from the ductile iron pipe (11) is closed; 6. Performing a water pressure test on the ductile iron pipe (11); 7. After the pressure test of the ductile iron pipe (11) is completed, the operator removes the plugging plate (13).

2. A pressure testing method according to claim 1, characterized in that: The strength of the pressure applied to the ductile iron pipe (11) and the steel pipe (12) in step 3 is half of the test pressure strength.

3. A pressure testing method according to claim 1, characterized in that: The water inlet branch pipes are all provided with check valves.

4. A ductile iron pipe pressure testing device according to claim 1 or 3, characterized in that: The ductile iron pipe (11) and the steel pipe (12) are both provided with a drainage pipe, and a drainage valve (5) is provided on the drainage pipe. The drainage pipe is connected to a water supply mechanism.

5. A pressure testing method according to claim 4, characterized in that: The drainage pipe is connected to the ductile iron pipe (11) and the steel pipe (12) via flanges.

6. A pressure testing method according to claim 1, characterized in that: The pressure measuring mechanism on the water inlet pipe is a pressure gauge II (7), and the pressure gauge II (7) is arranged on the water inlet pipe through a bracket.

7. A pressure testing method according to claim 6, characterized in that: It also includes an alarm, which is electrically connected to the pressure gauge II (7).

8. A pressure testing method according to claim 1, characterized in that: The steel pipe (12) is provided with a manhole for operators to enter and exit the steel pipe (12).

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