First, multiple choice questions
1, the most common damage form of economizer in operation is _ _ _ _ _ A _ _ _ _ _
A wear b internal corrosion c external corrosion d overheating
2. The total displacement of the safety valve on the drum and superheater must be _ _ _ _ a of the rated evaporation of the boiler.
There is no requirement that A is greater than B, equal to C and less than D.
3. Usually, there is a _ _ _ _ _ a _ _ radial clearance between the bearing outer ring and the bearing cover.
a 0.05-0. 1mm B 0.5- 1mm C 0. 1-0.5mm D 0.05-0. 1cm。
4. Stainless steel is corrosion-resistant by adding _ _ _ _ _ _ B _ _ metal.
A chromium and molybdenum b chromium and nickel c nickel and manganese
5, alloy steel superheater tube and reheater tube diameter creep deformation is greater than c, should be replaced in time.
a 1 B 2 C 2.5D 3
6. Operation (A B) in inflammable and explosive areas is regarded as hot work, and a hot work permit must be applied.
A electric drill b grinding wheel c trolley
7, in the flammable and explosive places (A B C D) for hot work permit.
A. Knock the concrete floor with steel tools; B. use electricity and gas welding; Use an electric soldering iron; D. Use knife-shaped electrical switches and non-explosion-proof lamps.
8. The research tool material is (A B C D).
A cast iron b low carbon steel c copper d babbitt alloy
9. The purpose of annealing treatment is.
A refining microstructure b reducing hardness c relieving stress
10 and 16Mn are the ones with high manganese content (b), and the average carbon content is 0. 16%.
A low alloy steel b ordinary carbon structural steel c high quality carbon steel
1 1. Replace the heat pipe. When the defect depth of the external surface of the new pipeline exceeds the specified thickness (b) of the pipeline, the pipeline cannot be used.
A 5 B 10 C 15
12, boiler door cover (such as inspection hole, soot blowing hole, manhole, etc. ) and the door frame joint surface must be close, the gap shall not be greater than (a) mm. ..
A 0.5 B 1 C 1.5
13. The total displacement of the safety valve of the steam boiler must be (c).
A is greater than the minimum continuous evaporation of the boiler, and B is less than the minimum continuous evaporation of the boiler.
C is greater than the maximum continuous evaporation of the boiler, and d is less than the maximum continuous evaporation of the boiler.
14, generally use (b) to check the sealing surface.
A lead powder b red lead powder c product blue d white lime water
15. The clearance between the valve packing gland, the packing cavity and the valve stem should be appropriate, which is generally ﹙ b ﹚ mm ..
A0.01-0.02mm b0.1-0.2mm c0.2-0.3mm d0.3-0.4mm.
16, the working speed of a shaft is 1500r/min, and the vibration value of its bearing is not allowed to exceed (b) mm. 。
A.0.08 b 0. 10 c 0. 12 d 0. 15
17, the thickness of the thin side of the inclined pad iron shall not be less than (c) mm. 。
A.2 B.3 C.4 D.5
18, and the clearance at the top of the keyway should be ﹙ b ﹚ mm. ..
a 0. 1-0.25 B 0.25-0.45 C 0.45-0.65D 1.0-2.0
19, carbon is the main combustible element in coal, and its content is generally (D).
a . 10-20 b . 20-30 c . 30-40d . 40-85
20, where there is no displacement on the pipeline, (a) should be installed.
A. fixed bracket B. sliding supports C. guide bracket D. spring hanger
2 1. When the speed of auxiliary machine is 1500r/min, the allowable deviation of circumference and end face of elastic coupling is less than (b) mm. 。
a . 0. 10 B . 0.08 C . 0.06d . 0.05
22. The working speed of a shaft is 1500r/min, and the vibration value of its bearing is not allowed to exceed (b) mm. 。
A.0.08 b 0. 10 c 0. 12 d 0. 15
23. The thickness of the thin side of the inclined pad iron shall not be less than (c) mm. 。
A.2 B.3 C.4 D.5
24. The length of straight pipe section set aside at both ends of elbow type elbow shall not be less than (d).
A.30mm B.40mm C.60mm D.70mm.
25, boiler wind pressure experiment generally use (B) to check the rigor of air preheater and hot air duct.
A. negative pressure method b positive pressure method c positive pressure method and negative pressure method
26. There is a Ping Jian with the dimension of 10h7, and the meaning of h7 is ﹙ B ﹚.
A base hole system, 7-level accuracy B base shaft system, 7-level accuracy C, deviation 0.7 D, and deviation 0.
27. The lubricating oil is dim and pasty, indicating that there is (B) in the oil.
A has pulverized coal, B has water, C has air and D has high temperature.
28, barrel ball mill hollow shaft sleeve thread direction inward and outward should be (A).
A is opposite, B is the same, C is opposite or D is parallel.
29. When hot assembling the bearing, put the bearing into the mineral oil in (c) and heat it.
About A 200℃, about B 200℃, about c 80 ~ 90℃
30, suction fan blades, impeller disc, wear head, wear plate wear more than the original thickness (a) should be replaced.
a . 1/2 b . 1/3 c . 2 \ 3d3/4
3 1. Hand-held electric tools shall be inspected regularly, with good insulation and solid and complete leads, and the longest lead shall not exceed (d) meters.
A 3 B 10 C 20 D 5
32, research tile, tile surface bright spot shows that (C)
A has no contact, the gap is large, B has no contact, the gap is small, C has the heaviest contact, D has contact, and the contact point is not obvious.
33. When measuring the clearance with a feeler gauge, the number of feeler gauge combinations should not exceed (A).
Three A tablets, one B tablet, two C tablets and a few D tablets will do.
34, general centrifugal fan impeller front plate and the clearance of the wind shell is (b) mm.
A 10~20 B 40~50 C 60~80 D 50~60
35. The level with an accuracy of 0.02mm/m is placed on the ruler of1000 mm. If one end of the ruler is raised by 0.02mm, the air bubble will shift (A).
A 1 B 2 C 3 D 4
36, bearing inner ring and shaft matching force is generally (D) mm.
a 2 ~ 5b 0.2 ~ 0.5 C 0. 1 ~ 0.4D 0.02 ~ 0.05
37. There is at least (A)mm gap between the inner sleeve and the end liner of the hollow shaft of the ball mill.
A 5 B 10 C 15 D 20
38, when the wear thickness of the steel tile in the ball mill exceeds the original thickness (B), it should be replaced.
A 50% B 60% C 65% D 55%
39, the expansion of alloy steel pipe can't be greater than the original diameter (a), the expansion of steel pipe can't be greater than the original diameter (a).
a 2.5% 3.5% B 3.5% 2.5% C 2.5% 2.5%
40. When the pipeline is butted, the distance between the weld center lines of two butt welds shall not be less than (A )mm, and shall not be less than the diameter of the pipeline.
A 150 B 200 C 250
4 1. When cold bending with a pipe bender, the bending radius shall not be less than (a) times of the external warping of the pipe.
A 2 B 3 C 4
42, low temperature sulfur corrosion of pipeline mainly occurs in (a).
A tube air preheater B economizer outlet C superheater
43, steel pipe bending, the biggest position of pipe wall thickness thinning is (C).
Starting point a, middle part of bend b, middle part of bend c, middle part of bend c.
44, pipeline and valve welding connection, the valve (a).
A must not be turned off, B must not be turned on, and C doesn't matter.
45, pipe with union connection, should pay attention to the direction of water flow (A).
A can be used from the male port of the connector to the female port B and from the female port of the connector to the male port C A and B..
46, flat welding flange assembly, pipe end should be inserted into the flange (B).
A 1/3 B 2/3 C 100
47, using hot bending heat stainless steel pipe, sand particle size of different diameters should choose (A).
A.b. Always use fine sand. The larger the pipe diameter, the thicker the sand is. No need for C.
48, forced circulation boiler compared with natural circulation boiler, in (b) increased the circulating pump.
A riser b downcomer c economizer
49, working pressure is greater than (A )Mpa steam drum, all belong to the scope of supervision of the metal body.
A 3.9 B 6 C 10
50, boiler header curvature is generally below (b).
a 1/ 1000 B 3/ 1000 C 5/ 1000
5 1. If the economizer tube is worn beyond the wall thickness (b), it should be replaced with a new tube.
A 1/2 B 1/3 C 1/4
52. The tubular air preheater is the most seriously worn when it is (A )mm away from the flue gas inlet.
A 20~50 B 30~70 C 50~ 100
53. When the temperature in the steam drum drops below (A )℃, it can only work, and it has good ventilation conditions.
A 40 B 50 C 60
54, 130t/h boiler shall be equipped with at least (d) safety valves.
A 0 B 1 C 2 D 3
55. The total displacement of the safety valve on the steam drum and superheater must be (a) the rated evaporation of the boiler.
There is no requirement that A is greater than B, equal to C and less than D.
56, safety valve should be (b) installed.
A tilt b vertical c depends on the convenience of field installation d level.
57, boiler superheater overpressure (a) the safety valve should be opened first.
Superheater b drum
58. When choosing a pressure gauge, the range of the pressure gauge should be (b) times of the working pressure.
A 1.5 B 2 C 3 D 4
59, when the boiler is running, the valve on the water level gauge pipe should be in (A) position.
A fully open b fully closed c middle position
60, check the boiler safety valve should generally be carried out in (a).
On the calibration platform of safety valve B in the running state of boiler A.
6 1, roller work, the line lamp voltage should choose (a) voltage.
A 12V B 24V C 36V
Second, the question of right and wrong:
1. The thickness of grinding powder commonly used in abrasives is indicated by particle size number. The smaller the number, the finer the grinding powder. ﹙ × ﹚
2. Before use, there should be no defects such as cracks, shrinkage cavities, slag inclusion, sand sticking, folding, missing welding and double skin on the surface of the medium and low pressure pipeline. ﹙√ ﹚
3, on the outside of the scaffolding working face, should be set up 1 m high railing. ﹙√﹚
4. When grinding the valve, the grinding tool is preferably made of alloy steel. ﹙×﹚
5. The clearance between the valve flange and the valve stem is 0.30-0.35 mm (XXX ××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××
6. When the valve is overhauled, the sealing surface should be polished, but the valve head and seat cannot be directly polished. ﹙√﹚
7. Generally, the inner wall of the welding counterpart shall be flush, and the staggered joints shall not exceed 10% of the wall thickness and not more than 1mm√.
8, alloy steel pipe should be heat treated in time after welding. ﹙√﹚
9. Under the influence of thermal stress, the initial position of pipeline elbow crack usually occurs on the outer surface. ﹙√﹚
10, the valve grinding process is divided into two processes: rough grinding and polishing. ﹙×﹚
1 1. If the damper of the fan is installed in the airflow direction, it will not only affect the output, but also cause great vibration. ( √ )
12. Rolling bearings have many advantages. In any case, it is better to use rolling bearings than sliding bearings. (× )
13, gear transmission is one of the most efficient commonly used transmission machinery, and its efficiency can reach 90%. ( √ )
14, fan blade extension can increase fan flow, wind pressure and power. ( √ )
15, the output of coal mill has nothing to do with ventilation. (× )
16, the allowable error of coupling timing generally decreases with the increase of rotating speed. ( √ )
17. When the local wear of the blade exceeds12 of the original thickness, a new impeller should be replaced. ( √ )
18, bearing axial clearance can be measured with feeler gauge and dial indicator. ( √ )
19. After cleaning the rolling bearing, wipe the roller cage clean with cotton yarn. ( × )
20, bearing and journal can't leave radial clearance, otherwise the connecting machine will produce vibration in operation. ( × )
Third, fill in the blanks:
1. The connection methods of pipes and accessories include flange connection, welding and threaded connection.
2. The desuperheater of 1-3 # boiler in Thermal Power Company is surface type, and the desuperheater of 4-6 # boiler is mixed spray type.
3. The total clearance between the valve core and the valve seat of the feed water control valve should be controlled at 0.3mm.
4.3632 Bearing inner diameter 160mm, and scrap clearance of 0.32mm.
5. Put the rolling bearing into the oil and slowly heat it to 80- 100℃. The maximum temperature shall not exceed 120℃.
6. Common faults of rolling bearings include rolling body peeling and peeling, overheating, discoloration and corrosion, crack or damage, etc.
7, worm gear and worm drive assembly, the axial movement of the worm is generally not more than 0.2 mm.. ..
8. The thickness reduction of the outermost wall of the elbow after bending shall not exceed 15% of the original wall thickness.
9. If the local wear of the blade exceeds 1/3 of the original thickness, it should be welded or repaired; If it exceeds 1/2 of the original thickness, a new impeller should be replaced. If there are any cracks in the impeller joint, the joint must be removed and welded again.
10, the clearance between the front disk of the fan impeller and the wind shell is 40-50 mm, and the clearance between the wind shell and the shaft is 2-3 mm. ..
1 1, there is at least 5 mm gap between the spiral drum of the coal mill and the end plate;
12, and the radial clearance between the discharging part and the feeding part of the coal mill and the spiral drum is 5-8 mm;
13, the discharging part and feeding part of the coal mill should extend into the spiral drum for 8-10 mm;
14. The contact angle between the hollow shaft and the tile is generally 60-90, and the contact between the shaft and the tile is even.
15, the tungsten-gold surface of the bearing bush should be intact, free from cracks, damage and bodiless, and the surface is silver. If the area with contact angle less than 25% is detached from the body or has other serious defects, it must be repaired by welding or cast with new tiles.
16, the thrust clearance of new tile spindle should be between 0.8- 1.2mm, and the old tile should be less than 3mm；;
17, the wear of the big gear of the coal mill is not more than 10- 15% of the original thickness, otherwise it should be turned over or replaced;
18. When replacing the valve, open the new valve for 2-3 turns before welding the new valve to prevent the valve head from bursting, jamming or jacking up the valve stem due to high temperature.
Fourth, the calculation questions:
1. As shown in the figure, the thickness of flattened lead wire on rolling bearing: thrust side b 1=0.25mm, bearing side B2 = 0. 15mm .. The thickness of flattened lead wire on both sides of bearing seat is thrust side A 1 = 0. 17mm. Should I add the thickness and position of the copper sheet? There are three kinds of copper sheets: 0.05 mm 0.10mm0.15mm.
Solution and load-bearing side: 0.15-0.21+0.25-/2 = 0.15-0.23 =-0.08-mm-is a tight force.
Thrust side: 0.25-0.17+0.20-/2 = 0.25-0.19 = 0.06-mm+is the clearance.
According to the cooperation between the bearing and the bearing upper cover, there should be a clearance of 0.05 mm-0.10 mm. Add 0. 15mm copper skin on both sides of the bearing seat and 0. 15mm copper skin on the upper part of the thrust side bearing.
2. Measure the alignment record of a motor with a dial indicator as shown in the figure. How to adjust the height of the motor foot? The fixture is on the motor side, and the diameter of the coupling wheel is 300mm﹚.
Solution: Because the b 1=b2 coupling has no opening, the motor is just below the mechanical side.
Motor low δ = (0.70-0.30)/2 = 0.20 (mm)
Therefore, a 0.20 mm gasket should be added to each of the four feet of the motor.
Verb (abbreviation of verb) short answer questions
1. What is the difference between the matching of sliding bearing bush and bearing cover and the matching of rolling bearing and bearing cover? Why?
Answer: (1) Generally speaking, the fit between the sliding bearing bushing and the bearing cover requires a tight force of 0.02 mm ... Too much tightening force is easy to deform the upper shoe; Too small tightening force will make the upper tile jump during operation.
(2) The clearance between the rolling bearing and the bearing cover is generally 0.05-0. 10mm. Because the rolling bearing is closely matched with the shaft, the rolling bearing will move with the shaft due to axial displacement during operation. If there is no clearance, the radial clearance of the bearing will disappear, and the bearing roller will get stuck and burn the bearing.
2. What are the causes of bending deformation of water wall tubes? How to fix it?
Answer: (1) Normal expansion is blocked;
(2) The pipe retractor and hook are burnt out;
(3) pipeline overheating;
Repair method: (1) furnace flatness: when the bending value and quantity of pipes are not large, the flatness is locally heated and carried out on site in the furnace.
(2) Out-of-furnace straightness: The bending value of pipes is large and there are many pipes, so they should be cut first, straightened outside the furnace, and bevelled. When put back in place, weld and number the cut pipes, and sit well when put back in place.
3. Why does the feed water control valve allow a certain leakage?
Answer: Generally, there is a certain leakage in regulating valves, mainly because there is a certain gap between the valve core and the valve seat. If the clearance is too small, it is easy to get stuck, which will make the operation difficult and even damage the valve. Of course, when the valve is completely closed, the leakage flow should be small. If the gap is too big, the building flow will be great. In an emergency, such as when the water level in the drum is high and water supply needs to be stopped, the boiler will be full of water due to large leakage flow. Therefore, the clearance between the valve core and the valve seat should be appropriate, which will not hinder the use, but also control the leakage flow in a small range.
4. What measures should be taken when checking the inside of the airbag?
Answer: There are many tube holes in airbags, so certain safety measures should be taken during maintenance to prevent sundries, parts or tools from falling into the tube holes, which poses a threat to operation safety, and at the same time, personal safety should be guaranteed. Therefore, when overhauling the drum, especially when entering the drum, the following points should be noted: (1) Before opening the drum, all valves connected to the drum and valves connected to the public * * * system (such as sewage valve, water supply valve, steam source valve of forest heating device, etc.) should be closed. ) should be closed, and install baffle, to ensure that the soda of public * * * system will not escape into the steam drum during maintenance. ⑵ When it is confirmed that there is no soda in the drum, it is allowed to slowly open the manhole door, and when the internal temperature is lower than 40℃, personnel are allowed to work in the drum. (3) The pipe hole on the steam drum should be covered with a special pipe sleeve or plugged with a pipe plug. Don't put a rubber pad under the drum to prevent sundries from falling into the pipe hole. (4) The drum room should be well ventilated, and 12V safety lights should be used for lighting. (5) When working in the drum, the substituted tools, materials and parts should be counted and registered, and the staff should have something in their pockets. [6] During maintenance, when the maintenance personnel leave the site and there is no work in the drum, the manhole door should be closed and sealed with a fake door made of wood or barbed wire. After the manhole door is finally closed, carefully check the inside and count the tools, parts and personnel to ensure safety.
5, superheater maintenance mainly check what aspects?
Answer: (1) Clean the dust on the external wall thoroughly. ⑵ Check the tube expansion. When the expansion of carbon steel pipe exceeds 3.5% of the original diameter, and the expansion of alloy steel pipe exceeds 2.5% of the original diameter, replace it with a new pipe. (3) Check the pipeline wear. When the wear area is greater than 10CM2 and the wear thickness exceeds 1/3 of the original wall thickness, a new pipe should be replaced. (4) Check the pipe for bending deformation. When bending deformation occurs, the causes of deformation should be found out and corrected and reset. 5] Check the steam-water and anti-wear devices of the pipeline, and check whether the steam-water and anti-wear devices of the pipeline are broken, damaged, deformed and welded. [6] Check whether there is any crack at the joint between the header and the desuperheater, whether the expansion is blocked, whether the support and hanger are damaged and hinder the expansion of the header, if necessary, cut the hand hole of the header to check whether there is corrosion and scaling inside, and whether there are cracks and other damages in the desuperheater spray chamber and protective sleeve.
Although it is not complete, it is basically enough. You can make some changes according to the actual situation of your factory. . . . . . I don't know if you are satisfied)