Three air control valve structure as shown in Figure 1.

Figure 1 Three air control valve structure (1. Cylinder block 2. Piston 3. Rod 4. Cylinder head 5. Roller assembly 6. Screw guide sleeve 7. Protective cover 8. Stem 9. Adjustment of wire sets 10. spiral sets of shell 11. valve 12. valve port 13. spool)

Three air control valve works as follows:

Figure 1 Three air control valve from the upper, middle and lower 3 parts, the upper part of a pair of acting cylinder, the middle is a rotating assembly of the lower part is a ball valve. Top of the cylinder when the piston 2, Ⅰ Ⅱ chamber cavity and connected, when the gas supply from P1 into the cylinder, the cylinder of the piston 2 in downward movement under pressure, the piston rod 3 drive rollers 5 driven along the screw guide sleeve shell downward spiral groove guide sleeve 6 to rotate, when the piston 2 moves down to the bottom of the cylinder, the screw guide sleeve rotated 90 °, screw driven ball valve stem guide sleeve 8 rotate 90 °, the spool 13 rotating 90 °, so isolation chamber cavity and Ⅱ Ⅰ, Ⅰ and Ⅲ chamber cavity connected.

Conversely, when the gas supply from P2 into the cylinder, the cylinder piston 2 in the upward movement under the pressure, the piston rod 3, the upward movement driven roller 5, rotating the screw guide sleeve 6, when the piston 2 moves upward to the top of the cylinder, the spiral guide sleeve rotating in the opposite direction 90 °, spiral valve stem guide sleeve 8 driven counter-rotating 90 °, counter-rotating spool 13, 90 °, so Ⅰ and Ⅲ chamber isolation chamber, Ⅰ Ⅱ chamber cavity and connected.

Three air control valve pneumatic solenoid valve controlled by P1, P2 and out of the mouth to control the air direction. Three air control valve for the fluid through the media, and the semi-fluid gas-liquid mixture.

Also available in: Chinese.

Keywords: safety valve; valve flap; opening pressure (set pressure); sealing pressure

Safety valve is widely used in boiler and pressure vessel overpressure relief device on, the performance can meet the requirements of the safe operation of boilers and pressure vessels is essential. According to the order requirements, the safety valve should be inspected regularly, at least once a year. “The steam boiler safety technology supervision order” under Article 145, for the newly installed boiler safety valve and safety valve after repair, but also to test its opening pressure (set pressure) and the sealing pressure.

China provides: steam boiler safety valve sealing test pressure to take 90% of opening pressure and reseating pressure of the lesser value. Air or other gases and water or other liquid with a safety valve sealing test pressure, when the open when the pressure is less than 0.30MPa, lower than the opening pressure 0.030MPa, when the opening pressure of 0.30 MPa greater than or equal to 90% when the opening pressure.

When conducting a safety valve sealing test, visual, or ears to the general method can be used to carry out. Check stations are usually based on pressure drop to determine eligibility, the pressure to rise when the check station set pressure is on, close all valves, pressure gauge value at this time check station at 2 minutes should be maintained or pressure drop is less than 0.01 MPa is considered qualified.

For more stringent safety valve, bubble method can be used to test the sealing pressure is normal. Easy way is the safety valve outlet, for a 5mm thick rubber sheet, under the outlet block valve half filled with water after the surface under the valve seat and valve are immersed in water, to maintain test pressure for 2 minutes, observed number of bubbles less than 30 that qualified.

In recent years, some manufacturers emphasis on economic efficiency, to the neglect of the product quality, leading to a safety valve for a certain number of poor manufacturing quality, geometry, precision error is larger, mainly the technical performance, manufacturing quality safety valve has caused a lot of use units of complaints. In addition, it is noteworthy that the current manufacture of some of the safety valve valve manufacturer in order to improve sealing performance and protect sealed off by reducing the width of the sealing surface of the ways in which the disc surface becomes very narrow. Such as emissions, due to high velocity impact erosion and the reasons for the back seat, causing damage to the sealing surface, seat surface ring injuries occur, especially in equipment over the working pressure safety valve more than 0.8MPa. Annual accounts for the city of such safety valve check valve should be about 5%, the city has a size of more than 2000 boilers, pressure vessels, nearly a thousand units each year check valve 3000. Narrow valve safety valve to check the maintenance work to bring a certain degree of difficulty, to make good sealing performance, you have to grind flat circular scars, these valves have an average of 20 just can not grinding. For example, in the annual inspection in the city 35 breweries relief valve, spring pressure rating is 1.0 ~ 1.3MPa, equipment operating working pressure 1.0MPa, of which there are five such valves, and all from the same valve manufacturers. Seating wide 4mm, valve sealing wide only 1.5mm, narrow valve did not cause enough attention to the relevant departments.

We verify these in real understanding of the work, high work pressure in the equipment operation, safety valve opens too many times the case, the valve sealing surface is too narrow and the valve does not meet state standards, is caused by valve ring injuries the main reason. To this end, the proposed safety valve manufacturers in the design, processing time, we should focus on considering valve sealing surface is not too narrow.

Also available in: Chinese.

Key words: diesel engine; valve; surface inspection

1. Cause valve failure and the need for surface inspection

Diesel engine valve in the service process, the downtime caused by failure, resulting in economic losses. Diesel engine valve failure are the following three reasons: First, as the valve can not be reset while the Pistons hit touched off; Second, poor body raw materials (such as surface cracks, inclusions, etc.) caused during the manufacturing process defects (such as forging cracks, stress concentration due to machining marks and microcracks formed in service); third, the body flow by heat stress and heat stress corrosion cracks generated.

Data show that import and exhaust valve rupture or severe burning right, the valve falling debris occurred broke the piston cylinder head combustion surface and the top surface of the phenomenon, sometimes occurring broke into the exhaust pipe and other major turbocharger accidents, these incidents not only affect the safe operation, but also caused huge economic losses.

According to analysis, the crack edge to the center by the development, due to welding heat-resistant alloy valve sealing surface, only crack in this ring bring out the slit, they had this ring for valve materials with low heat capacity surfacing materials in a wide crack to the center of the development of increasingly narrow crack. When the direction of development on the edge of the crack bend and soon falling pieces.

To prevent accidents, avoid unnecessary losses, should be in each repair, overhaul period, the surface of the valve to conduct a comprehensive examination, including macro-inspection, surface inspection and so on.

The current surface inspection, the general color penetration testing and magnetic particle testing, these two methods for detection of pieces of different shapes were, in the application of their own characteristics and limitations. Previous check valve used only for coloring the surface of penetration testing or macroscopic examination only, but this easily lead to missed. Valve for the accurate detection of surface flaws, I try to use colored penetrant and magnetic particle testing process of combining detection of valve to obtain good results.

2. Testing process

Colored penetrant testing is generally used in portable pressure tanks agent, generally used in portable magnetic particle inspection yoke magnetic flaw detector. Taking into account the need to use magnetic suspension magnetic particle inspection, cleaning storm standards, so the detection of valve surface, the first arrangement to do color testing, magnetic particle testing to do before.

2.1 Color penetration testing

Color detection using solvent cleaning agents, the general steps are: pre-cleaning solvent cleaning → penetration → imaging observation. Test parts of the surface conditions significantly affect the quality of color penetration testing, so special attention must be pre-cleaning should be the elimination of prejudice depth penetrant oil, coke, oxide and other fixtures. Defects in the attachment and residual oil in and water, can be chemically valve soaking. After the removal of pollutants, cleaning agents for cleaning the valve body, to be dried and kept moist spray penetrant state 15 ~ 30min, the humidity at 15 ~ 50 ℃. Penetration of toilet paper after wiping with a dry cloth or excess penetrant, and then use a cloth moistened with cleaning agents in one direction to block or clean the toilet paper, detergent spray cans can not be directly sprayed on the surface cleaning. Wipe disable cotton waste, because of its easy to stay in the filament fragments on the surface and difficult to remove, the formation of pseudo-time imaging revealed that affect the test results.

Solvent-based color detection-type display of imaging agents for the drying agent. Spraying, imaging agents to fully shake the spray cans, spray evenly to imaging agent were seized at the surface. Distance control when spraying in the 300 ~ 400mm, angle and spray cans were seized on the surface into 30 ~ 40 ° is appropriate, the use of scanning, and thin coating should be uniform in order to just cover the subjects area is appropriate. Imaging agent in the coating were observed after 7min, defective parts may show a red mark, which is due to capillary action principle, white imaging agent into the valve surface breaking defects in the red penetrant adsorption up to show the true shape of wheel defects Gallery traces.

2.2 Magnetic Particle Testing

Penetrant inspection of the valve by the color, wipe clean with a cloth, you can use the portable magnetic particle inspection machine valve surface magnetization. To ensure the sensitivity of magnetic particle testing, generally used A30/100 type specimens placed in the test specimen within the edge of the groove side surface was seized, placed a certain distance across the specimen. In order to check the surface of the specimen is in good contact with can be used transparent tape to paste formed on the surface being seized, and note that tape does not cover the artificial defects on the specimen. Magnetization should pay attention to the direction of the magnetic yoke walk and pouring position of the magnetic suspension, each region was seized at least two independent testing should be carried out, testing the two should be roughly the direction of magnetic field lines perpendicular to each other, each magnetized area should be 15mm overlap in order to find the vertical and horizontal (circumferential) surface and near surface defects, and to prevent undetected, to improve defect detection rate.

3 Conclusion

Color penetration testing is a simple, intuitive display defects, surface breaking defect detection sensitivity, etc., but in oil, water and gas to run the larger environment of parts, if the surface oil, coke and other attachments are not thoroughly cleaned, will affect the test results; magnetic detection of low cost, the advantages of speed detection, but also for near-surface defects can be clearly shown, but it was seized by the size and shape of pieces of restrictions on complexity. Thus, after the first colored penetrant Magnetic particle flaw detection process technology two way valve on the diesel engine for surface inspection, a separate complementary use of color detection or lack of magnetic exploration methods to ensure quality and reliability testing. This method shows a clear visual image, to retain good, high sensitivity, the shape is not limited pieces were seized, and easy to use and flexible. I used this method in addition to valve manufacturers for testing diesel engine valves, but also the method applied to the valve factory the inner surface of the cylinder generator sets, power plant valve guide bearing block bearing against the top and other parts of the surface inspection, have achieved good results.

Also available in: Chinese.

Key words: pipe; jet; frost valve

1. Introduction

In northern China, mostly in winter minimum temperature -30 ℃ ~ -20 ℃ between the individual areas of up to -40 ℃, frozen earth depth is generally between 0.5m ~ 1.5m, this winter for the rural and urban water use is very difficult. At present, the water industry, the existing antifreeze device or complex, higher prices; or drip serious, the use is not ideal. We successfully developed based on the principle of jet pipes FDJ-100-I-type jet freeze valve device to overcome the shortcomings of the antifreeze, the antifreeze has a good effect.

2. Structure and working principle

Figure 1: The main water inlet pipe 6 by the cut-off valve 5, the jet valve 8, water storage tank 7, the outlet pipe composed of 1 and 2 pedals. Inlet pressure of 6 and water tower or water tank connected. Jet valve 8, water tank 7, the inlet valve 5 and 6 are installed in the ground insulation room.

Depresses the pedal 2, the drive cable 4 to 5 open the valve, water flow into the jet valve 8. 8 jet valve installed inside a pipe, the pipe diameter thinning, so that water flow rate suddenly accelerates, and shooting at the outlet pipe. At the same time, due to the acceleration of water flow in pipes at a certain negative pressure, the water storage tank 7 in the negative pressure and gravity are brought into the outlet pipe 1 with the injection.

Release the pedal 2, the cut-off valve under the action of 5 reduction in the spring, runoff water tower or the pressure tank is broken, the water in the outlet pipe 1 through the outlet pipe back into the water storage tank 7. Frozen layer of earth to ensure the outlet pipe 1 is not in storage, to freeze target.

3. test results

Test results below.

4. Technical performance

1) Dimensions: length × width × height = 300mm × 70mm × 1590mm.

2) The following frost depth of 1m.

5. Features

1) simple and compact structure, small size, low manufacturing cost, frost effects, easy to use.

2) the jet pipe and the combination of clever storage tank to solve the general problem of antifreeze leaking valve.

3) Each open once the water storage tank to be updated, will not cause water pollution and water waste.

4) Low water pressure requirements for good performance.

6. prospects

FDJ-100-I-type jet valve for frost in northern China in winter in rural and urban water. By changing the volume of water storage tanks, antifreeze can be adapted to different depths, the market prospect is broad.

Also available in: Chinese.

1. the function

The function of shut-off valve switch is connected or cut off access to two-line speed control valve air brake valve on the gas line between the shut-off valve.

2. the use of time

When traveling on level ground or loader operations, should be shut-off valve switch to “ON ‘position. Thus, when the tread brake valve under the gas pedal, the gas turned on; from the air brake pressure over gas (0.45 ~ 0.65MPa), part of the brake master cylinder to the liquid, the other through the cut-off valve switch, enter the pay-speed control valve shut-off valve on the control of the cylinder; cylinder piston to overcome the return spring tension, to promote the shut-off valve stem forward, cutting shift circuit, the high pressure oil sump cited backcross cruise control, shift clutch friction plate separation, the transmission will cut off their own power. brake cut off the power transmission system, it can enable mechanical brake is sensitive, good effect, but also saves fuel.

When traveling on the ramp or loader operations, should be shut-off valve switch to “off” position. Thus, when the tread brake valve under the gas pedal, because of gas cut off from the air over the part of the brake pressure gas, can not switch off the valve, shut-off valve control cylinder piston can not move forward, cut off the valve stem fixed and the normal shift circuit, the clutch still keep working, delivery speed detector hanging from stalls. Braking power transmission system can not be cut off when the brake pedal when relaxed, machinery can be quickly started; when parking in the ramp period, but also effectively prevent slope sliding mechanical phenomena occur, driving or operating machinery safety protection.

3. use method

Pull the left “on” (when the brake pedal, shift oil pressure gauge pointer quickly put to zero); right pull “cut off” (when the brake pedal, shift oil pressure gauge pointer is still point to the normal 1.1 ~ 1.5MPa).

Also available in: Chinese

Standards and technical requirements based on business, I use two 0.2 50kPa pressure gauge micro, small air compressor (with tanks), regulators, stopwatch, hoses and other test system components, see below.

Open air compressor and storage tank valve, the use of pressure regulating valve (through the pressure valve control system as a whole) will be transferred to micro-manometer pressure A shows a value slightly larger than 25kPa, automatic valve is turned off, micro-pressure meter B should be zero pressure, pressure for 5 minutes, observe the micro-manometer zero change in B, test performance and closing the automatic valve stem to open the top insurance pressure. Adjust the pressure to down 1kPa, manual lever on the valve opens automatically provide a smooth pressure to 25kPa, A, B micro pressure gauge pressure should be equal, that is, automatic valve in the channel state, pressure for 5 minutes, observe the micro-manometer B pressure variation, is the automatic valve sealing performance test value. Buck slowly again until the automatic valve closed, pressure is off the record (ie, the critical working pressure) and the off time. Re-open the automatic valve, pressure regulator boost to 0.5kPa (working pressure), pressure for 15 minutes, down from the observation of open bar, test pressure losses. Repeat the test three times, can be derived can meet the business requirements of the standard test results.

Also available in: Chinese

LSAR50/50 rotary valve feeder speed 8r/min; motor 3kW, 380V, 1500r/min; by the sprocket, the device output to 50m³/h.

The feeder and put into operation a year later, circumstances arise in the normal load stall, and the problem is getting worse. Maintenance once every two weeks before, one week after the repair, sometimes twice. The reason there are two main aspects: First, the rotor and wheel wear, the relative gap increases, a large number from the end face of the rotor into the gray, so that the rotor and the wheel cover the face clearance Yi was filled with ash, causing the rotor rotational resistance increases , as well as equipment downtime, when the motor temperature is very high due to the load, could easily lead to motor burn. Second, following the spiral feeder humidifiers work, to be carried out on the water bottom ash, bottom ash as high temperature, part of the water vapor from the feeder into the feeder below the rotor and wheel hub cover the gap between the inside face, ash mixed with water vapor, in the case of high temperature friction and adhesion at both ends quickly agglomerate surface, the rotor resistance increases, as well as motor overload shutdown.

In response to these problems, we conducted a two improvements (Figure 1):

Figure 1 (1. Rotors 2. Wheel hub 3. Cover 4. Circular plate 5. Convex edge)

(1) in the bottom ash into the feeder at the entrance, near the end by welding an arc-shaped baffle 4 (the rotor and the Arc of the gap 1 ~ 3mm), to prevent dust into the rotor end.

(2) feeder wheel cover 3, 5 on the welding of two convex edges, so that access to the material between the rotor and end caps can be gray or caking which would burst into the convex edge spiral humidifier.

Improved equipment running well over the past year, no recurrence of these problems, not only satisfy the production needs, but also reduce maintenance labor intensity.

Also available in: Chinese

1. Failure Analysis

One-way trip is the role of cutting knife sets back the process in fast one-way valve to open, work feed off when the check valve, flow control orifice through the cam into the oil, in order to achieve the work feed; throttle Size is no problem from the mechanical control, which can only be a fault in the check valve seal. The circular form of check valve with steel ball, as both are rigid contact, frequent fatigue damage to the switch so that the orifice, sealing reduce accidents; while oil may be due to particle pollution, easily attached to the rigid contact of the seal surface, so that the one-way valve closed, it can lead to bar knife, causing the accident.

2. Solutions to determine

First, repair ball contact surface with the hammer, the result is very low success rate, not the total elimination of hidden trouble; then, through careful study, a bold vision aspects of changing the rigid contact, so used to replace the ball as the rubber ball, bakelite ball method, however, because of the two balls after a test failed to wear; final seal holes by changing the material to test, from copper, aluminum, nylon and other soft materials were screened, and ultimately select the nylon, because the material has good toughness and flexibility, and thus have very good contacts with the steel ball sealing and longer life. Proven effective.

3. Improvement

The original seal bore face, with the flat top diamond cutting 3 ~ 4mm deep, and then add a circle system with a Teflon pad car, pay attention to seal holes to moderate chamfer. Rubber pad and the body to use real closure to prevent leakage.

4. Effect

Using this method our company has 30 one-way trip on the throttle has been transformed, the effect is very good, the life greatly extended. Fundamentally eliminate the bar knife phenomenon, the company has created considerable benefits.

Also available in: Chinese

To address this problem, the valve manufacturer for the life of valve failure analysis and statistics, found that many still use the valve was replaced, the main reasons are:

1. Lift limiter valve on the radial block a lot of wear and tear guide so that the valve and the guide block between the gap of about 0.2mm into a 1mm ~ 2mm (see Figure 1), so the valve can not fall after exercise deviates from the correct position of the valve seat sealing surface. Especially high-pressure section of the valve.

Solution: Replace the worn out the lift limiter.

2. Valve seat sealing surface after the repair process, tends to become very shallow groove on the valve seat, so lift limiter boss on the bottom groove to withstand the seat, and sometimes even the boss will not achieve positioning effect, resulting in a deviation from the valve seat sealing surface.

Solution: In the process, while processing the seat sealing surface groove bottom, the depth of the groove to maintain the original, so that the average life ring valve can reach more than six months.

Figure 1

Also available in: Chinese

Sanitary pneumatic control valve designed to ensure the use of angle from the discharge valve, standard electronic polished, smooth surface to ensure clean and free of media accumulation area, no potential contamination. Quick disassembly Body and bonnet of the valve to open and repair quick and easy, making the process downtime.

First, the pneumatic valve sanitary valve

Body Type: Angle valve casting ball

DN: 15~100

PN: 1.0

Connection: clamp type, threaded, flanged

Bonnet Type: Standard -17 ~ +230 ℃, high temperature +230 ~ +450 ℃

Gland Type: Bolt Clamp

Seal Packing: EPDM, PTFE

Second, the pneumatic control valve sanitary trim

Spool forms: single-seat piston-type valve

Flow characteristics: linear, equal percentage

Sanitary pneumatic valve actuators and accessories, the role of the form

Actuator Name: ZHA/B thin film multi-spring actuators

Actuator Type: ZHA/B-22、ZHA/B-23、ZHAB-34

Effective area (cm²): 350、350、560

Stroke (mm): 10、16、25、40

Spring Range: 1.5~3kg/cm²（0.15~0.3MPa）

Diaphragm materials: EPDM clip nylon

Air connection: RC1/4"

Ambient temperature: -30~+70℃

Can be equipped with accessories: positioning, air filter pressure reducer, to secure his position valve, limit switch, valve position transmitter, hand wheel, etc.

Role Type: Gas Off-type (B) – Loss of air pressure valve to open (FO); gas open (K) – Loss of air pressure valve off (FC)

Also available in: Chinese