To achieve graded differential speed for the slot ironing, facilitate maintenance and transportation, the mainstream slot irons worldwide are designed as modular multi-roller connections with graded flat modules and block packaging and transportation. This requires professional assembly and commissioning of the equipment at the user's site. The graded installation of the slot iron involves the following key points (Note: the following requirements also apply to fault analysis and routine maintenance checks).
Adjusting level and position: The parallelism between the front and rear slot rollers of the slot iron is crucial to the overall machine's operational performance. Any non-parallelism will cause skewing of the linen and equipment malfunction. Therefore, after the equipment is positioned, the level, parallelism, and accurate spacing of the front and rear slot rollers must be carefully adjusted and checked. The equipment should be placed on a flat concrete floor, and the base should be leveled using a level instrument. Appropriate shims (such as metal plates, wedges, or similar objects) should be used during installation and then fixed in place. The elevation of each section of the ironing machine must be the same and leveled across the entire working width using a level instrument. Note that the final precise adjustment can only be made after the ironing machine is heated.
Connecting the bridge plate: The bridge plate connection is a key installation requirement for the slot iron. Many ironing faults are caused by the linen not running smoothly at the bridge. Its installation follows the "staggered lap joint principle" (including the front feeding mechanism), meaning the front stage components extend beyond the rear stage components by a certain position. The front end of the bridge should be inserted into the groove opened at the rear of the front slot, and the rear end should extend beyond the front connection end of the rear slot. It is strictly forbidden to install the bridge with the front end protruding or the rear end recessed, or even flush installation, because thermal deformation during operation will cause the linen to be obstructed by the protruding step, resulting in ironing faults.
Installing the steam system: The installation of the steam system is a key factor determining whether the slot iron can work efficiently. Figure 5 shows a typical external steam supply pipeline installation diagram for the slot iron. The following points should be noted:
Steam and condensate pipelines should be connected according to pressure specifications. Especially when the steam heat source is far away, the diameter of the steam supply pipeline must be large enough to meet the requirements;
The equipment's steam inlet pipe should be connected from the upper part of the main pipeline because the upper end of the main pipeline is steam, while the lower end is water-steam mixture, which is unfavorable for normal heating.
To improve steam supply quality, the end of the main pipe should be sealed with a steam trap valve and connected to the condensate pipe;
Manual shut-off valves should be installed on the equipment's inlet and outlet pipelines to facilitate maintenance and operational control;
A pressure gauge should be installed at the equipment's steam inlet pipeline end for monitoring. If the steam pressure in the pipeline exceeds the specified requirement, a pressure reducing valve should be installed;
Exposed steam pipelines should be wrapped with insulation materials to reduce heat loss and ensure safety.
Installing the exhaust system: The installation of the external exhaust system needs to avoid increased pressure loss and reduced exhaust caused by errors in diameter size, elbow type, and exhaust pipeline connections, which would reduce the machine's ironing capacity. The exhaust pipes installed in the laundry room should be made according to the following principles:
Minimize the use of elbows, and avoid using sharp or narrow round elbows or T-shaped tees, as these will cause exhaust resistance;
The allowable straight length of the exhaust pipe for double-roller slot irons is approximately 17m , and the allowable length decreases when elbows are used;
It is best to discharge the exhaust pipe directly outdoors and avoid installing branch pipelines as much as possible; if branch pipelines must be installed, the main pipeline diameter should be increased and care taken to avoid negative pressure backflow inside the main pipeline. It is best to add an independent fan for the main pipeline;
The inspection index for the negative pressure of moisture extraction on the test roller should not be less than 300MPa, with a moisture discharge rate of 0.2 to 0.3 liters per minute, which is appropriate; generally, the exhaust volume of the front stage should be greater than the rear stage, for example, for double rollers, 60% and 40% respectively; for triple rollers, 55%, 35%, and 10% respectively.
Installing the felt: Some slot ironing rollers have felts directly wrapped on the ironing rollers and do not require special installation. However, some slot irons require the felt to be rewrapped on site during installation. This is also an important part of slot iron installation and maintenance. The steps are as follows:
Lift the roller and prepare two felts (felt length 5030mm and width for 800mm diameter rollers 3600mm , specification 7009 - m ''), pull the felt from the rear end of the equipment forward, align the center of the felt width with the center of the roller width, and make the starting edge of the felt flush and tightly attached to the roller spring belt surface.
The front end of the felt is fixed to the roller using stainless steel wire 1, which must be threaded through the holes in the roller, with at least ten evenly distributed attachment points.
Start the roller rotating slowly forward, pull the rear end flat so that the felt winds along the roller rotation direction. After rotating 270 degrees, press the roller down. Care should be taken to avoid the spring directly contacting the slot surface;
After the felt is wrapped twice around the roller, let the end of the felt slightly overlap the starting end, then press down and fix the excess felt on both sides;
Under steam pressure of about 0.6MPa, run the roller for 3 hours to break in. Try to make the starting and ending edges of the felt match, and the overlap length of the third layer should not be too long, about 20mm, with excess trimmed off.
Slot roller status check:
After installing the ironing felt and running for a period of break-in, measure the circumference of the ironing roller with a special measuring ruler (or directly with a guide tape), then calculate the diameter of the ironing roller. Generally, 800mm for slot irons with diameter 0.6-0.8MPa steam pressure, the normal ironing roller diameter should be 803 -804mm , and the upper and lower limits can be appropriately selected according to the steam size. If the ironing roller diameter is too large, a thinner ironing felt should be chosen; conversely, a thicker felt should be selected.
Raise and lower the ironing roller, place the pressure gauge between the feed slot and the roller, and measure the pressure value. During normal operation, it should be maintained at 40 g /cm² - 80g /cm² (the maximum value corresponds to a cylinder back pressure of 0.4MPa). The pressure can be adjusted according to the type of fabric being ironed by adjusting the cylinder back pressure (ensure the pressure values on both left and right sides are even). It is recommended that the normal back pressure should not exceed 0.2MPa to avoid excessive wear of the ironing felt.
Adjustment and inspection of speed difference: The front and rear speed ratio of the ironing roller (the ratio of the rear roller speed to the front roller speed) is generally adjusted within (1 + 0.005 ~ 0.025) times (based on achieving the required ironing effect), to moderately maintain the pulling force of the rear roller on the linen. The speed difference should not be too large or too small; too large will cause the guide belt to break or damage the linen, too small will make it difficult to eliminate wrinkles on the linen. The general adjustment method is:
Stop the machine and mark the same position on the front and rear rollers;
After running at a constant speed for 10 revolutions, keep the front roller position unchanged and measure the distance "A" that the rear roller mark deviates from the starting position;
If the value deviates significantly (negative values are not allowed), adjust the rear drum by changing the diameter of the pulley to alter the transmission ratio so that A = 80 ~ 100mm approximately.
Heating system debugging: After the steam system is installed, the following methods can be used for testing and inspection (Note: This method is also effective for daily startup and maintenance operations):
Slowly and carefully open the steam valve on the pipeline until the sound of steam flow is heard (and check for any leaks in the pipeline);
The steam pressure will slowly rise, after 20 minutes the pressure will increase to about 0.4MPa, and the valve can be opened a bit more;
When the machine pressure reaches 0.7-0.8MPa after 30-40 minutes, the steam can be fully opened;
Note: During the first operation, steam should not be directly introduced into the machine; it should first be vented to remove impurities in the pipeline; by comparing the inlet steam temperature and outlet steam temperature difference, the heating condition of the ironing machine can be understood; if there is a temperature deviation, check the steam trap; heating time must not be shortened; if the steam valve is opened too quickly, it will cause a "water hammer" effect, damaging the pressure gauge and steam trap; rapid heating will cause excessive thermal stress in the heating tank, greatly shortening its lifespan (thermal stress is caused by the temperature in the steam chamber and heat passage rising faster than the temperature of the reinforcing ribs).
Electrical control debugging: Due to differences in equipment from various manufacturers, please refer to the electrical control section of the respective equipment manuals; omitted here.
