Pig Quick Open Closure

Description

Initial Installation

The initial installation of Quick Open Closure shall be carried out according to the following requirements:

1. The inner diameter of the quick opening closure is consistent with the inner diameter of the equipment. And the butt clearance is uniform. The difference between the maximum and minimum butt clearance is ≤ 1.0mm. The butt misalignment amount meets the provisions of Table 1 in the GB150.4-2011 standard. When the wall thickness is inconsistent. It shall be calculated according to the thinner of the two;
2. Before the quick opening closure is assembled with the equipment cylinder, the welding type shall be determined first. 1) If double-sided welding is adopted, the head cover shall be removed. 2) If single-side welding is adopted. Only the sealing ring shall be removed without removing the head cover;
3. Before welding the Quick Open Closure and the equipment cylinder. Carefully read welding and welding deformation control and suggestions on post weld heat treatment in this manual;

Disassembly of head cover

1. When the head cover needs to be removed for assembly and maintenance of quick opening blind. Please comply with the following regulations:
2. Place the quick opening closure flat, open the clamp according to the opening of the head cover in 3.0 of this manual;
3. As shown in Figure, remove the upper-end cover of the adjusting shaft, and loosen the adjusting bolts. And then remove the adjusting shaft. During disassembly, attention shall be paid to preventing the thread from knocking, bumping, scratching, and injury.
4. Remove the head cover with the cooperation of the crane.
5. During the operation, one person must command and others must cooperate to prevent accidents and bumps. Scratches and injuries on the sealing surface, threads, and other machined surfaces. And mark the disassembled parts and keep them properly.

Welding and welding deformation control

Welding deformation can be caused by weld shrinkage or improper welding operation during welding. In order to prevent and reduce welding deformation, the assembly and welding of it and the equipment cylinder shall be carried out according to the following requirements:

1. The butt joint clearance shall be uniform, and the maximum and minimum butt joint clearance shall be ≤ 1.0mm
2. The misalignment of the butt joint shall comply with the provisions in Table 1 of the GB150.4 standard. When the butt wall thickness is inconsistent, it shall be calculated according to the thinner one.
3. Before welding, the groove shall be preheated at a temperature of 80 ~ 100 ℃, or in accordance with the provisions of the welding process;
4. During welding, the welding methods of small diameter electrode, small current, and symmetrical welding. And multi-layer welding must be adopted to control the welding deformation, otherwise. The head cover may not be opened and closed, and even the quick opening closure may be scrapped. This is very important!
5. The weldment on the equipment barrel shall try to stay away from the circumferential weld between the quick opening blind plate and the equipment barrel as far as possible.

Suggestions on post weld heat treatment

1. When heat treatment is carried out for the circumferential weld between it and the equipment barrel, local heat treatment shall be adopted as far as possible.
2. If it is specified in the technical requirements of the equipment manufacturing general drawing that the equipment must be subject to overall heat treatment. The sealing surface must be protected with rock wool. Aluminum silicate or other thermal insulation materials to prevent excessive oxidation from affecting the sealing;
3. The heat treatment process shall be carried out in strict accordance with Article 8.2 of GB150.4 or ASME standards. Or according to the mature heat treatment process of the heat treatment manufacturer.
4. Please note: 1) if the head cover has been removed before heat treatment, please install the head cover after heat treatment. 2) If the head cover is not removed before heat treatment, be sure to remove all sealing rings. 3) After heat treatment, the sealing surface shall be slightly wiped clean with a fine abrasive cloth. And it is evenly coated with lubricating grease, glycerin, or antirust oil.

Coating

Before painting the Quick Open Closure, the safety interlock must be removed and all sealing surfaces.

Reassembly of Head Cover

When reinstalling the head cover, please follow the following requirements:

1. Firstly, all sealing surfaces shall be protected against corrosion. See the maintenance section of this manual for specific operations;
2. And then remove the sealing ring. With the cooperation of the crane, close the sealing surface of the head cover with the sealing surface of the cylinder flange, and make the outer circle flush. After alignment, move the center of the head cover slightly upward and fix it

(Note: due to the accumulated tolerance during assembly and the self-weight of the head cover. The head cover will have a downward vertical displacement when opening the blind plate after assembly. The purpose of moving the head cover center slightly upward is to correct this displacement)

1. Firstly, assemble the adjusting shaft and tighten the 8 adjusting bolts at the upper and lower ends of the adjusting shaft. Special warning: when tightening the adjusting bolt, the adjustment shaft must be absolutely prevented from moving in any direction.
2. Install the upper-end cover of the adjusting shaft;
3. Conduct 2 ~ 3 opening and closing tests, fine-tune the lower four sides of the adjusting shaft with a wrench, and adjust the alignment of the head cover

Operation

Opening of Head Cover

1. Before opening the head cover, be sure to confirm that the equipment has been vented and blowdown, and strictly abide by the safety operation procedures.
2. Turn the safety interlock knob to open the safety interlock. At this time, if there is residual pressure in the equipment, stop the operation immediately. Recheck whether the vent valve and blowdown valve of the equipment are open. And wait for complete venting and blowdown of the equipment and pressure relief of the safety interlock.
3. When it is determined that there is no residual pressure in the equipment , the opening operation can be continued, as shown in Figure 1.0:

1) First rotate the opening and closing lead screw with a special wrench according to the direction indicated by the sign. So as to slowly open the three-valve clamp. When the clamp rises to such an extent that it does not affect the opening of the head cover. Hold the handle and pull outward to open the head cover.

2) When the opening angle of the head cover is greater than 90 °. Rotate the positioning handwheel to fix the head cover to prevent the head cover from swinging and hurting people.

Opening and closing of head cover

1. Firstly, before closing the head cover, the sealing surface and sealing groove must be thoroughly cleaned and wiped.
2. Wipe the sealing ring clean and check its surface for cracks, scratches, permanent deformation, bulging, chemical damage and other defects. No matter which defect is found, it must be replaced;
3. Apply a layer of antirust grease evenly in the sealing groove and on the sealing surface. And then carefully install the sealing ring into the sealing groove. (Note: first install it in the direction of 12 and 6 o’clock and press it. And then install it in the direction of 3 and 9 o’clock);
4. Unscrew the positioning hand wheel of the head cover to release the positioning. Then hold the handle, close the head cover and press it. Hold the special wrench with the other hand, and rotate the opening and closing lead screw according to the direction indicated on the label. So that the three-valve clamp slowly shrinks to the center until the two sealing surfaces fully fit;
5. At last, rotate the knob of the safety interlock to insert the two plugs at the front end into the corresponding holes of the clamp. Note: pay attention to observation during operation.

Note:

(1) No matter whether the opening and closing lead screw or the safety interlock knob is rotated. It shall not be operated forcibly;
(2) During operation, if it is not smooth or stuck, stop to find the cause.

Storage

If the Quick Open Closure needs to be stored, even if the storage time is short. It is necessary to remove the sealing ring, thoroughly clean and wipe the sealing groove and sealing surface. Evenly apply anti rust oil. And then reinstall the sealing ring into the sealing groove. Then wrap the quick opening closure with plastic cloth and put it into the packing box for storage. Quick opening closure must be stored indoors. If the air humidity in the storage environment is high, desiccant shall be considered for moisture-proof. The storage life of the rubber seal ring is 2 years. If it is re examined, no problems can be found, and the storage period can be extended for 1 years. The storage conditions of rubber sealing rings are as follows:

Temperature: the storage ambient temperature shall not exceed 25 ℃, and low temperature has little effect on rubber
Light: avoid direct sunlight and strong ultraviolet radiation, and keep it in an opaque box.
Oxygen: the sealing ring shall be packed to avoid air circulation.
Deformation: the storage environment of the sealing ring shall be loose enough to avoid extrusion by external force and mutual extrusin.
Others: other storage methods such as “hanging” can be considered. If it is hung for storage, it cannot be hung in one point. And the hanging point shall be smooth without convex and sharp points

Withstand voltage test

Whether it is the pressure test before the equipment leaves the factory. The pressure test after installation on the construction site, or the overhaul pressure test during equipment operation. It must be carried out in strict accordance with the following requirements:

1. Firstly, open the head cover according to 3.0 of this manual;
2. Secondly, remove the sealing ring, clean the sealing groove and sealing surface, and completely remove all sundries. Such as water stain, rust, oil scale and dirt, wipe them clean, and then evenly apply anti rust grease;
3. And then wipe the sealing ring clean and check the surface for scratches, indentation, permanent deformation and other damages or defects. If any damages or defects are found, they must be replaced;
4. Install the sealing ring, first install it at 12 o’clock and 6 o’clock, and press and hold it. And then install it at 3 o’clock and 9 o’clock.
5. Close the head cover according to the closure and locking of the head cover in this manual.
6. And last, other operations for voltage withstand test.

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