Newly opened factory recruits captain of paperboard production line

Examination questions of pulping and papermaking specialty

I. Fill in the blanks:

1. According to the different specific gravity, there are two ways to purify pulp, namely.

2. The main factors affecting the efficiency of desander are,,,

、 。

3. The screening efficiency does not change with the increase of the number of screening cycles, but decreases. When the series increases, the screening efficiency is greatly improved, but on the other hand, the unit product

Greatly increased.

4. Beating is mainly to make fibers,

Harmony, harmony, harmony.

5. The factors that affect the beating efficiency of disc mill are,,,;

6. At present, rectifier components used in headbox are,,,

,, and so on.

7, paper machine according to the position of its transmission device can be divided into,.

8. Rinse the papermaking net with clear water.

Three kinds.

9. Lifting devices of the press section are, and.

Three types.

10, the difference between paper and cardboard lies in its sum.

1 1, papermaking "three rates" refers to,,.

Second, the noun explanation:

1, hit:

2. Size:

3. Beating degree:

4. Grid:

5, pulp speed ratio:

Third, question and answer:

1. How does beating affect the strength of paper and the combination of fibers?

2. Briefly describe the function of press section of paper machine?

3. What is embossing? How to avoid embossing?

4. What are the main factors that affect the paper evenness?

5. What is the difference between soft calendering and ordinary calendering?

Answer:

I. Fill in the blanks:

1, gravity settlement, centrifugal separation

2, pressure difference, slurry concentration, throughput, slag discharge.

3. Fiber loss rate and flow cost

4. The outer layers of primary wall and secondary wall are broken, swollen by water absorption, fiberized and cut off, resulting in fiber fragments and other secondary effects.

5. Paper throughput, refining concentration, refining specific pressure and grinding disc tooth profile.

6. Tube bundles, stepped diffusers, orifice plates, floating plates, blades and sheets;

7. Left and right mobile phones

8, fixed nozzle cleaning, fixed fan nozzle cleaning, high-pressure mobile water needle cleaning.

9. Lever hammer, pneumatic and hydraulic.

10, quantitative thickness

1 1, replication rate, yield, qualified rate

Second, the noun explanation:

1. Beating: mechanical treatment of fiber suspension in water by physical methods, so that the fiber is subjected to shear force, the shape of the fiber is changed, and the pulp obtains certain characteristics, thus ensuring that the manufactured products meet the expected quality requirements;

2. Sizing: refers to the treatment of pulp, paper or paperboard to obtain the performance of resisting liquid penetration.

3. Beating degree: it reflects the difficulty of pulp dewatering and comprehensively represents the beating effect of fiber cutting, splitting, swelling and hydration;

4. Mesh: refers to the number of warp threads within the width of 1 inch.

5. Slurry speed ratio: refers to the ratio of the slurry injection speed at the lip of the headbox of the paper machine to the running speed of the forming wire of the paper machine;

Third, question and answer:

1, a: The beating quality directly affects the low strength and cohesion. Good beating quality can produce high strength paper. The lack of paper strength is attributed to the lack of fiber cohesion. Strength is determined by many reasons, depending on the mutual cohesion between fibers, fiber length, fiber strength, fiber surface condition and fiber arrangement. In a word, the strength of paper comes from the binding force of fibers, that is, the degree of hydrogen bonding.

2. Answer: Remove the moisture from the paper; Increase the fiber binding force of paper, improve the tightness and strength of paper; Conveying the wet paper web from the wire part to the drying cylinder part for drying; Eliminate the net mark of the paper web, improve the smoothness of the paper and reduce the two sides of the paper.

3. Answer: The pressure on the wet paper during pressing is too great, which causes the paper to collapse. This phenomenon is called embossing; In order to avoid embossing, the paper pressing pressure should be gradually increased and the dryness of the paper pressing should be improved.

4. Answer: (1) The net concentration is too high and the dispersion is not good; (2) The size is too thick and there are many long fibers.

(3) The beating degree is low and the dehydration is too fast. (4) The difference between the pulp speed and the net speed is too great. (5) The vacuum degree of the vacuum box or vacuum dewatering plate is not enough.

5. Answer: (1) Soft calendering adopts double-roll calendering, and the lower roll is a controllable medium-high roll. (2) Soft calendering can improve the surface properties of paper while ensuring the uniformity of tightness, while ordinary calendering can only improve the thickness uniformity. (3) Soft calendering can better improve the surface properties of paper by acting at high temperature.