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 coal mine hydraulic supports, including testing methods, inspection rules, marking, packaging, transportation, and storage. It applies to various types of automatic spray control valves installed on coal mine hydraulic supports.

2 Reference Standards

The following standards contain provisions that, through reference in this standard, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, 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 Procedures and Sampling Tables for Nonconforming Rate in 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 Support with Emulsified Oil

3 Definitions

This standard uses the following definitions:

  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 support handle is operated to move the support, the device uses working fluid to automatically open or close the spray waterway (referred to as the control valve).
  2. Working Liquid Emulsion: The emulsion used to open or close the control valve, which has a certain pressure.
  3. Opening Pressure: The minimum pressure required to open the control valve, measured in MPa.

4 Requirements

Control valves must comply with the provisions of this standard and be manufactured according to the drawings and technical documents approved by the prescribed procedures.

4.1 Ambient Temperature

Normal operation under ambient temperatures ranging from 4°C to 40°C.

4.2 Appearance

The surface should be smooth and have an anti-corrosion protective layer that is uniform, without flaking or scratches. There should be no deformation, cracking, corrosion, or mechanical damage. The water inlet, outlet, and working fluid inlet should be clearly marked. The nameplate should be securely installed and legible.

4.3 Interface

The inlet, outlet, and working fluid inlet interfaces should be quick connectors. Their size and surface roughness should meet the requirements specified in Appendix A of this standard. After testing, there should be no leakage at the interface.

4.4 Strength

The control valve is rated for a fluid pressure of 32 MPa. It should be tested at 1.5 times the rated working pressure at the inlet for 5 minutes without any leakage, and the shell and parts should not deform or sustain damage.

4.5 Resistance Loss

When water flows through the control valve at a rate of 20 L/min, the pressure difference between the inlet and outlet ports should not exceed 0.1 MPa.

4.6 Opening Pressure

The opening pressure should not exceed 2 MPa when the water pressure is within the range of 1.0 to 7.0 MPa.

4.7 Operating Water Pressure

The control valve should be able to open and close normally when the operating water pressure is within the range of 1.0 to 7.0 MPa. During the test, it should not exhibit any automatic opening or closing phenomenon.

4.8 Service Life

After 4,000 cycles, the seal should still meet the requirements outlined in section 4.9.

4.9 Sealing

According to Table 1, the sealing test should show no pressure drop. After a 2-hour regulator test under the working fluid rated pressure and operating water pressure range, the working fluid should not experience any pressure loss.

5 Test Methods

5.1 Test System

The test system is shown in Figure 1.

Hydraulic support with automatic spray control valve test system

5.2 Test Equipment and Tools

  1. Pressure Gauge: Range of 0–1.6 MPa and 0–40 MPa, accuracy of 1.5.
  2. Flow Meter: Rated pressure ≥ 7.0 MPa, rated flow ≥ 30 L/min.
  3. Stopwatch: Ordinary mechanical or electronic stopwatch.
  4. Water Sprayer Pump: Rated pressure ≥ 7.0 MPa, rated flow ≥ 30 L/min.
  5. Working Fluid Pump: Rated pressure ≥ 32 MPa.
  6. Valve: Hydraulic support valve.
  7. Counter: Blood cell counter.
  8. Pressure Device: Rated pressure ≥ 48 MPa.

5.3 Test Conditions

  1. Test water temperature: 4°C to 40°C.
  2. 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.
  3. Working fluid temperature: 10°C to 50°C.
  4. Both spray water and working fluid should be filtered with a filter of 0.125 mm accuracy.
  5. The outlet of the control valve should be connected to a certain number of nozzles to meet the flow rate requirements during resistance measurement.

5.4 Test Items and Methods

Table 1 outlines the test items and methods for the control valve.

Table 1: Control Valve Test Items and Methods

Serial Number Test Item Test Method
1 Ambient Temperature Test under ambient temperature of 4°C to 40°C.
2 Appearance Visual inspection.
3 Interface Connect the control valve to the test system, supply water to the working fluid inlet for 2 minutes, and observe for seepage or leakage.
4 Strength Apply pressure at 1.5 times the rated working pressure at the inlet for 5 minutes.
5 Resistance Loss Open the control valve and measure the pressure difference between the inlet and outlet at a flow rate of 20 L/min.
6 Opening Pressure Adjust the water pressure to 1.0–7.0 MPa and the working fluid pressure to 0.1 MPa below, then gradually increase the working fluid pressure until the control valve opens, recording the highest pressure gauge reading. Perform five tests for each pressure level.
7 Operating Water Pressure Adjust the water pressure to 1.0–7.0 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, then cycle the control valve open and close 4,000 times.
9 Seal (1) After completing the life test (not required for factory inspection); (2) The working fluid should show no pressure drop after a 2-hour test under rated working fluid pressure and operating water pressure.

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