课程测试题一

课程测试题一:陕西科技大学试题纸课程: 包装技术基础（双语授课）班级: 包装 03 级 * 班学号: ********* 姓名: * * *一、 Packaging Terms ( 名词解释 ) (15 points ) ：（用中文解释下面术语）packaging; corrugated board; Tetra Pak; MAP; thermoplastics二、 True or False ( 判断题 ) (16 points) ：1. Typically, the inform/sell function plays a more significant role in industrial packaging.2. To prevent a product from damage resulted from vibration, the protective packaging should take into account the resonant frequencies of the product.3. Vacuum packaging can be used in fruits and vegetables.4. Immediate advantages of two-piece cans are reduced metal usage, improved appearance, and the elimination of a possible leakage location.5. Double Wall refers to three sheets of linerboard with two mediums in between.6. Paper properties depends upon the paper's directionality7. If the g-factor is estimated too low, the product will be under-packaged.8. Significant compressive creep will lead to the packaged item loosening in the cushion.三、 Multiple Choices( 单选题 ) (30 points) ：( The 15 choices are based upon the following message)Liquid Constant Level FillingIntroduction. Although there may be slight variations in the sizes or shapes of bottles and jars, it is frequently desirable to have the fill line at the same height on each container so that all of them appear to be filled exactly the same when they are on the display shelf. Some manu facturers deliberately add extra product and overfill some of their “see through” containers in order to improve their appear ance and to guarantee that all of them contain at least the minimum desired amount of product.In this section you will learn the operation of five basic methods used for constant level filling of still liquids and semi-liquids and one method used for filling carbonated products. You will also learn ways in which each method is used and their basic machine maintenance requirements.Molding and forming techniques can cause minor irregularities in the sizes of shapes of rigid glass and plastic bottles and jars, and some semi-rigid containers may also change their shape and volume slightly during the filling process. It is frequently more economical to use additional product in the oversized containers than it would be to more closely control the forming processes 1 . Constant level filling techniques compensate for the minor changes and variations in the containers and produce the uniform appearance that is important in the sale of many products in “see through” containers.Pure Gravity Filling. Pure gravity(Figure 20.14) is not only one of the oldest and simplest constant level filling methods, but it is also one of the most accurate ones for filling free-flowing products. Some gravity fillers can eliminate the need for overflow and recirculation of the product, and some can hold aeration of the product to a minimum.Pure gravity filling can be used for most still liquids and some semi-solids. Products with consistencies as heavy as catsup or mustard can be filled in this way, but care must be taken with the heavier products to assure that the temperature and consistency of the product is maintained at a level at which the product flows freely and evenly. Although the constant level fillers can be adjusted to automatically operate at slower speeds when the product flows more slowly, this change in rate of flow can affect the timing of the conveying system and other machines in the packaging line.The product flow is produced in the pure gravity system by locating the product supply tank high enough so that forces of gravity can be used to move the product through the feed mechanisms into the containers.The flow is started and stopped by the action of a spring loaded filling valve that is opened by the force of making contact with the top of the container. Some machines place the container on a platform and raise it upagainst the valve in the filler head, and others lower the filler head down onto the top of the container.When the pressure of the contact is sufficient, the spring opens the filling valve, and the product flows fromFigure 20.14 Pure gravity fillingthe supply tank into the container. In the machine shown in the above illustration, the air in the container is forced out through the vent tube as the product enters the container, and when the liquid covers the port of the vent tube the air can no longer escape. The backpressure stops the flow of product into the container.When the contact between the filler head and the container is broken the spring closes the filler valve and prevents dripping of the product as the head is removed from the container and positioned for the next fill.Some other types of gravity fillers use timing devices to open and close the valves to control the flow of product into the containers. Instead of an air vent tube, an overflow pipe is located at the fill line to carry any excess product into an overflow tank from which it can be pumped back into the supply tank. This type of system does not require a tight seal between the container and the filler head.The maintenance requirements of the pure gravity filling system are relatively simple. The filler components must be kept clean and well lubricated, and the bearings, bushings, and springs must be replaced when they wear excessively. The movement of the machine parts must be monitored and adjustments made to time and position them correctly for the fill level that is desired.The consistency of the product and the free movement of all moving parts are critical for smooth operation. Underfill may be caused by constriction of the air vent tube or by failure of sufficient product to move into the container during the time period it is under the filler head.Figure 20.15 Pure vacuum fillingPure Vacuum Filling. Pure vacuum filling systems (Figure 20.15) are used primarily for filling narrow necked glass bottles with still liquids. It is not normally used with plastic or other non-rigid containers, because the vacuum pressure that is used to draw the product from the storage tank into the container can cause non-rigid containers to contract and become distorted .As shown in Figure 20.15, the vacuum tube within the filling sleeve is connected to a vacuum chamber which is maintained at a constant vacuum level by a vacuum pump.When the bottle is in position, an airtight seal is established between the top of the bottle and the filler head. As the valves are opened a vacuum is drawn on the bottle, and this pressure differential draws the product from the supply tank into the bottle. The fill level is determined by the position of the vacuum port in the bottle, because the excess product is drawn out through the port. The length of the fill time is usually controlled by a cam operation or some other type of timing mechanism.The product overflow from the container is drawn through the vacuum port into the vacuum chamber on which a vacuum is maintained by the action of the vacuum pump. The excess product is pumped back into the supply tank.The pure vacuum filling system is generally faster than a pure gravity system, but the vacuum system always has some overflow and recirculation of product. The vacuum filler works only when there is a seal between the bottle and filler valve, so chipped or cracked bottles can not be filled.A vacuum level of between 25 and 28 inches of mercury is normally maintained to provide smooth and efficient operation, but the level may vary on different machines as a result of the differences in manufacturers' designs and specifications.The vacuum filler is somewhat more difficult to clean than a simple gravity system because of its complexity and small vacuum tubes that can become plugged. All the fittings must be kept tight for efficient operation.The sealing washers must be replaced when they show signs of damage or wear, and the replacements should always be of the recommended type and material.Care should be taken to assure that the proper type of filling nozzle is always used for the product being filled, because foaming, aeration, and splashing can be increased by rapid movement of the product.Figure 20.16 Gravity vacuum fillingGravity Vacuum Filling. Gravity vacuum filling systems (Figure 20.16) combine the features of both the gravity and the vacuum systems. A light vacuum of from 3 to 5 inches of mercury is maintained in the system to assist in drawing the air out of the containers and to stabilize the flow of the liquid.In the filler shown in Figure 20.16 a light vacuum is maintained in the area above the product in the supply tank, and the vent tube from the container opens into this area of the supply tank. When the seal is established between the filler head and the bottle the vent is opened, and a vacuum is automatically drawn in the container. This vacuum in the container helps make the product flow into it more rapidly and smoothly.As in the gravity filling systems, when the product reaches the fill level the vent port is closed by the rising liquid, and the flow stops.The gravity vacuum system does not have the overflow or recirculation of product that is inherent in the pure vacuum system, and it produces minimum amounts of turbulence and aeration of the product. This type of system is particularly well suited to filling distilled spirits and wine because there is virtually no loss of proof.Since the filling nozzle is spring loaded and operated only when the vacuum is present, a chipped or cracked bottle on which a seal is not formed will not be filled.The vacuum gravity system must be kept clean and clear of any obstructions that could affect the flow through the vacuum tubes. The seals and connections are critical and should always be kept tight and replaced when signs of wear appear.Pure Pressure Filling. In pure pressure filing systems (Figure 20.17), the product is pumped from a storage tank through a filling valve and into the container. The product storage tank may be located external to the machine or as an integral part of it.Figure 20.17 Pure pressure fillingA product pump draws the product from the supply tank, and applies the pressure necessary to pump it into the containers.The filling valve contains an overflow tube to drain the excess product back to the supply tank and prevent overfill. The fill level of the container is determined by the location of the overflow port in this tube within the neck of the container. When the product reaches the overflow port, the fill is completed, but the flow continues through the overflow tube until the seal on the container is broken and the valve sleeve covers the ports in the filling nozzle and stops the flow.Pure pressure filling is normally used for still liquids, but it can be applied to a wide variety of products with different consistencies.Applying pressure to the product may tend to increase splashing or foaming, so particular care should be taken to insure that the appropriate nozzle styles and sizes are used and that the recommended pump speeds and pressure settings are used.Regular cleaning and lubrication of all moving parts according to the manufacturers' recommendations is required to keep the machines in the top operating condition. Cleaning of the nozzles at the end of each run is particularly important with heavier products or materials that can build-up in the nozzles and tubes.Level Sensing Filling. Level sensing (Figure 20.18) makes it possible to fill containers to a level without establishing an airtight seal between the tops of the containers and the filler valves. It is used primarily for high speed filling of small necked plastic and glass bottles. The fill level is very accurate, and there is no need for product recirculation.A pressure of up to 15 psig is applied to force the product from the supply tank through the product valve and into the bottle.Since there is no seal the displaced air escapes out of the top of the bottle around the product tube.The sensing device operates by directing a stream of low pressure air at the filling station andFigure 20.18 Level sensing fillingdetecting changes in the resistance to the air flow.The positioning of the filler and the start of the flow can be initiated when the sensing device detects the presence of the empty bottle in the filling station. When the product has filled to the desired level, the sensing unit signals the interface valve to stop the flow.Filling FilledThe sensing air tube is located inside the filler tube, so it must be kept clean and free of obstruction. A small build-up of product inside the sensing air tube could cause differences in the unit's sensitivity and cause underfills.The product tube is frequently designed for a particular product and bottle design, and may contain screens or other features to reduce turbulence or foaming. A new filler tube may be required when changes are made in either the product or the container.Pressure Gravity Filling. Carbonated beverages can lose some of their carbonation during the filling process if they are handled roughly or exposed to open atmosphere. Pressure gravity filling (Figure 20.19) is a process that was developed specifically to help hold the CO 2 in the carbonated beverages during the filling operation. This method is used almost exclusively for filling beverages such as sodas, beer, sparkling wines, and champagnes into bottles or cans.In the pressure gravity filling operation a pressure of between 15 and 125 psig is maintained in the headspace of the product supply tank to help hold the CO 2 in solution. Otherwise the filling is basically a gravity filling process.Figure 20.19 Pressure gravity fillingFilling FilledWhen the container is sealed to the filling valve a mechanical latch opens a charging valve at the top of the valve vent tube. This establishes in the container the same pressure level that is being applied to the surface of the product in the supply tank. The product is in a totally pressurized environment. This pressure does not interfere with the filling process, but it does prevent the loss of carbonation.After the pressure in the container is equalized with that in the supply tank, the spring loaded filler valve opens and the product flows into the container by gravity until the vent port is covered and the flow is stopped as in a normal gravity filling process.The filling valve also contains a mechanical snift port which opens the headspace of each filled container to the atmosphere in order to gently release the pressure from the filled container and prevent gushing when the seal is broken and the filler head is removed from the container.1.The volume of product in each container is more accurate witha. constant level fillingb. level sensing fillingc. volumetric filling2.The force that moves the product in a gravity filler is produced bya. location of the supply tankb. rotary pumpsc. vacuum pressure3.On gravity fillers the vent tube location determinesa. the amount of overflowb. the fill linec. backpressure4.Pure vacuum fillers are normally used witha. glass bottlesb. plastic bottlesc. metal cans5.In a pure vacuum systema. there is no product overflowb. product overflow returns directly to the supply tankc. product overflow is drawn into the vacuum chamber6.A tight seal between the container and the filler head is required ona. all gravity filling systemsb. pure vacuum filling systemsc. both the above7.The speed of the pure vacuum system isa. faster than the pure gravity systemb. slower than the pure gravity systemc. about the same as the pure gravity system8. Gravity vacuum fillers are used largely for fillinga. carbonated beveragesb. winesc. semi-liquid products9.Some gravity vacuum fillers will fill a chipped bottlea. trueb. false10.The fill level of a pure pressure filler is determined by the location ofa. the sensing elementb. the overflow tubec. the vent tube11.The air from a bottle filled by a level sensing system escapesa. through the vent tubeb. through the overflow tubec. through the top of the bottle12.The sensing unit on a level sensing filler is operated bya. photo electric cellsb. low pressure airc. mechanical detectors13.The most important maintenance requirement for filler isa. cleaning and lubricationb. adjustmentc. overhaul14.The pressure in a pressure gravity filler is used toa. move the productb. keep the product in solutionc. prevent splashing and foaming15.The purpose of the snift port on a pressure gravity filler is toa. determine the fill levelb. permit overflowc. release pressure from the container四、 Questions ( 回答题 ) (15 points ) ：( 用中文或英语回答 )１．包装的功能是什么？２．产品脆值的定义是什么？３．纸板的‘基础重量'指什么？４．什么是材料的动态缓冲曲线？５．什么是包装线？五、 Discussion ( 论述题 ) (24 points) ：（基于所学内容，自选一‘包装专题'用中文论述）参考答案和评分标准（课程测试题一）一、每题 3分，共15分packaging : 包装。