General technical requirements for automatic spray control valves for hydraulic supports
Ministry of Coal Industry of the People's Republic of China, approved on December 30, 1997, and implemented on June 1, 1998.
1. Scope
This standard specifies the requirements for automatic spray control valves used in hydraulic supports, testing methods, inspection rules, markings, packaging, transportation, and storage.
This standard applies to hydraulic supports in coal mines that are equipped with various types of automatic spray control valves.
2. References
The following standards contain provisions that, through reference in this standard, constitute the provisions of this standard. At the time of publication, the editions indicated were valid. All standards may be revised, and parties using this standard should explore the possibility of using the latest version of the standard.
GB 191-90 Pictorial Marks for Packaging and Storage
GB/T 6388-86 Transport Package Delivery Mark
GB/T 13264-91 Sampling Inspection Procedures and Sampling Tables for Nonconforming Rate of Small Batch
GB/T 14437-93 Sampling Inspection Procedures for Product Quality (for Larger Total Amounts)
GB/T 15482-1995 Sampling Test Procedures and Sampling Tables for Product Quality Supervision (Small Overall Count)
MT 76-83 Hydraulic Supports with Emulsified Oil
3. Definitions
This standard uses the following definitions:
3.1 Hydraulic Support with Automatic Spray Control Valve
A device installed on a coal mine hydraulic support and connected to the corresponding hydraulic pipeline. When the handle of the support is operated to move the support, the device uses working fluid to automatically open or close the spray waterway (hereinafter referred to as the control valve).
3.2 Working Fluid Emulsion
The emulsion used to open or close the control valve and has a certain pressure.
3.3 Opening Pressure
The minimum pressure required to open the control valve, in MPa.
4. Requirements
Control valves must comply with the provisions of this standard and be manufactured according to drawings and technical documents approved by the prescribed procedures.
4.1 Ambient Temperature
Normal conditions at an ambient temperature of 4 to 40 ℃.
4.2 Appearance
The surface should be smooth, with an anti-corrosion protective layer that is uniform, without flaking or scratches. The shell should not be deformed, cracked, corroded, or mechanically damaged. Clearly marked water inlet, outlet, and working fluid inlet holes. The nameplate should be securely installed and clearly labeled.
4.3 Interface
The inlet, outlet, and working fluid inlet hole interfaces should be quick connectors. The interface size and surface roughness should meet the requirements of Appendix A of this standard. After testing, there should be no leakage from the interface.
4.4 Strength
The rated pressure of the control valve fluid is 32 MPa. It should be tested at 1.5 times the rated working pressure from the inlet, with no liquid discharge and no deformation or damage to the shell or parts.
4.5 Resistance Loss
When water flows through the control valve at 20 L/min, the pressure difference between the inlet and outlet ports should not exceed 0.1 MPa.
4.6 Opening Pressure
Within a water pressure range of 1.0 to 7.0 MPa, the opening pressure should not exceed 2 MPa.
4.7 Operating Water Pressure
When the operating water pressure is within the range of 1.0 to 7.0 MPa, the control valve should be able to open and close normally. During the test, the control valve should not exhibit automatic opening or closing phenomena.
4.8 Service Life
After 4,000 cycles, the seal should still comply with the requirements of section 4.9.
4.9 Sealing
Using the sealing test method in Table 1, the test pressure should show no pressure drop. Under the working fluid rated pressure and operating water pressure range, after a 2-hour regulator test, the working fluid should not have any pressure drop.
5. Test Methods
5.1 Test System
The test system is shown in Figure 1.
5.2 Test Equipment and Devices
5.2.1 Pressure Gauge: Range of 0 ~ 1.6 MPa and 0 ~ 40 MPa, accuracy of 1.5.
5.2.2 Meter: Rated pressure ≥ 7.0 MPa, rated flow ≥ 30 L/min.
5.2.3 Stopwatch: Ordinary mechanical stopwatch or electronic stopwatch.
5.2.4 Spray Pump: Rated pressure ≥ 7.0 MPa, rated flow ≥ 30 L/min.
5.2.5 Working Fluid Pump: Rated pressure ≥ 32 MPa.
5.2.6 Valve: Hydraulic support valve.
5.2.7 Counter: Blood cell counter.
5.2.8 Pressure Device: Rated pressure ≥ 48 MPa.
5.3 Test Conditions
5.3.1 Test spray water temperature: 4 ℃ ~ 40 ℃.
5.3.2 Test working fluid: Emulsified oil or rust-proof low-condensable No. 5 hydraulic oil formulated according to MT 76-83, mixed with neutral soft water in a 5:95 weight ratio.
5.3.3 Working fluid temperature controlled at 10 ℃ ~ 50 ℃.
5.3.4 Spray water and working fluid should be filtered with a filter accuracy of 0.125 mm.
5.3.5 The outlet of the control valve should be connected with a certain number of nozzles to meet the flow rate requirements during resistance measurement.
5.4 Test Items and Methods
The test items and methods for the control valve are listed in Table 1.
Table 1: Control Valve Test Items and Methods
|
Serial Number |
Test Item |
Test Method |
|
1 |
Ambient Temperature |
Test under ambient temperature of 4 ℃ ~ 40 ℃. |
|
2 |
Appearance |
Visual inspection. |
|
3 |
Interface |
Connect the control valve to the test system, supply water to the working fluid inlet for 2 minutes. Observe each hole for seepage or working fluid leakage. |
|
4 |
Strength |
Use the pressure device to apply 1.5 times the rated working pressure at the inlet for 5 minutes. |
|
5 |
Resistance Loss |
Open the control valve and set the water flow to 20 L/min. Record the pressure difference between the inlet and outlet ports. |
|
6 |
Opening Pressure |
Close the control valve, adjust the water supply pressure to 1.0–7.0 MPa and the working fluid pressure to 0.1 MPa below. Then set the valve to open position and gradually increase the working fluid pressure until the control valve just opens. Record the highest pressure gauge reading when the valve is open. Conduct five tests for each pressure level. |
|
7 |
Operating Water Pressure |
Adjust the water supply pressure to 7.0–1.0 MPa and open/close the control valve for 5 minutes. Conduct five continuous tests for each pressure level. |
|
8 |
Life Test |
Adjust the working fluid pressure to 5–6 MPa and the water pressure to 1.5–2.0 MPa. Open the control valve, and immediately shut it down after the water passes to complete one cycle. Repeat this process 4,000 times. |
|
9 |
Seal |
(1) After completing the life test (not required for factory inspection); |
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