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TECHNICAL INSPECTION OF JACKS
Each rack, screw and hydraulic jack must have a technical passport of the manufacturer and a plate indicating the lifting capacity.
Jacks in service are subject to technical examination and testing in accordance with clause 5.53 SNIP ΙΙΙ-Α.ΙΙ-62 at least after 12 months.
The test of jacks during the technical examination must be carried out for a static load exceeding the maximum rated carrying capacity by at least 10%. The jack must be under this load for 10 minutes, and the screw (rail, rod) must be extended to the uppermost position. Have hydraulic jacks by the end of the test, no more than 5% pressure drop is allowed. The test results are entered in the passport.
What are the jacks
A jack is a device that uses force to lift heavy loads. The basic mechanism by which the force is applied varies depending on the specific type of socket, but it is usually a screw thread or a hydraulic cylinder. Shafts can be classified according to the type of force they use: mechanical or hydraulic. Mechanical jacks such as car jacks and jacks, lift heavy equipment and are rated based on lifting capacity. Hydraulic jacks tend to be more powerful and can lift heavier loads higher and include bottle jacks and floor jacks.
UNIVERSAL STAND FOR TESTING RIGGING EQUIPMENT
In fig. 5-7 shows a universal stand designed for testing blocks, hoists, jacks and mounting belts for a maximum load of 15 tons.
Figure: 5-7. Universal rig for testing rigging equipment,
The stand consists of a reinforced concrete foundation on which two supporting I-beams 1 are fixed. Two pipes 2 0 219X4.5 mm, 12 m high, are installed on the beams' consoles.
A crossbar 3 moves along the pipes, on which a dynamometer 4 is fixed, two rods 5 are also fixed to the crossbar for testing jacks. A fixed block is attached to the upper beam 6, a winch 7 is installed on the beams 1. A plate 8 is welded to the consoles of the beams 1, and plate 9 is welded to it, in which, as in the cross member 3, there is a hole for the thrust, with which they can be connected to each other with a friend.
When testing slings, blocks and hoists, this thrust must be installed, and when testing jacks it is removed.
The load on the tested slings, blocks and jacks is created by a winch through a chain hoist system; the load on the hoists can be created by the hoists themselves The load is indicated by a dynamometer.
Depends on the force generated by the pressure. Basically, if two cylinders are connected and force is applied to one cylinder, the same pressure is generated in both cylinders. However, since one cylinder has a larger area, the force generated by the larger cylinder will be higher, although the pressure in the two cylinders will remain the same. Hydraulic jacks depend on this basic principle for lifting heavy loads: they use plunger pumps to move oil through two cylinders. The plunger is first pulled back, which exposes the suction valve ball inside and draws oil into the pump chamber.
Reliable and trouble-free operation of the pumping unit largely depends on how correctly the design, material of units and parts are selected, as well as how the hydraulic parameters of the unit correspond to the features of the technological scheme in which it is installed.
The nature of the extinguishing agent outflow, hydraulic parameters and effective range * of the explosion suppressor
When the plunger is pushed forward, oil travels through the external relief check valve into the cylinder chamber and the suction valve closes, creating pressure inside the cylinder. Two common types of hydraulic jacks include bottle jacks and floor jacks.
Also called hand jacks, bottle jacks provide an easy way for a person to lift a vehicle for inspection or service on the road. Their resemblance to milk bottles has earned the name of bottles - today they are sized and weighted to offer lifting capacities of one hundred to several tons. The bottle nests have a vertical shaft that supports a platform that directly transfers the weight of the object as it is lifted.
The use of a pyrotechnic composition as a gas generator makes it possible to provide the required mode ~ pressure of the working fluid, and, consequently, the necessary hydraulic parameters of the outflow and delivery of the extinguishing agent to the combustion zone.
Sprinkler hydraulic parameters:
Hydraulic parameters of the sprinkler EG-3.5:
While they are most commonly used in the automotive industry, bottle connectors have other uses as well. In the medical industry, they can be used in hydraulic stretchers and patient lifts. In industrial applications, they can be found as pipe bending machines used in plumbing, as cable slicers for electrical projects, and as material elevators in warehouses. Their ability to lift heavy loads plays a large role in the repair of large agricultural equipment and in many construction works.
EG-12 sprinkler hydraulic parameters:
The generator with a two-jet spray GDS-3,7 * has the following hydraulic parameters:
The GCHS generator has a four-jet sprayer and is an upgrade of the GDS generator. Below are the hydraulic parameters of the generator:
Water pipelines for various purposes should be used as a source of water supply for water fire extinguishing installations. If the hydraulic parameters of the water supply (pressure, flow) do not provide the design parameters of the installation, it should be provided pumping station to increase the pressure.
Bottle sockets can be framed, mounted on a beam, or simply used to facilitate transportation. Unlike shafts with openings for bottles, the shaft is in a horizontal position - the shaft presses on a crank, which connects to a lifting platform, which then rises horizontally. Floor jacks generally provide a greater vertical lift range than bottle jacks and are available in two sizes. The original jack is about four feet long, one foot wide and weighs about 200 pounds - they can lift 4-10 tons.
Irrigation maps at. using an involute sprinkler (sprinkler or drencher) are shown in Fig. V-14. Sprinkler hydraulic parameters are given in table. V-6.
Table V-6. Sprinkler hydraulic parameters
jacking devices were installed on the columns, with the help of which the covering elements and crane beams were lifted to the design height; at the same time, four overhead cranes were securely attached to the crane girders. Then the old columns were cut and the upper part of the building frame with an area of \u200b\u200babout 4 thousand m2 was lifted to a height of 6 m. The total weight of the structures being lifted was 800 tons; their lifting was carried out using 24 hydraulic jacks with a lifting capacity of 400 tf for 10 days.
The jacks are tested for a load that exceeds the ultimate carrying capacity by at least 10%. The jack should be kept under this load for 10 minutes. The test should be carried out with the screw, rail or rod fully extended. Jacks should be tested once a year. For hydraulic jacks, a pressure drop of no more than 5% is allowed within 10 minutes. For rack and pinion jacks, thread or tooth wear is allowed no more than 10%.
The test of jacks during the technical examination should be carried out at least after 12 months for a static load exceeding the rated carrying capacity by 10%. The jack must be under this load for 10 minutes, and the screw (rail, rod) must be extended to the extreme upper position. For hydraulic jacks, a pressure drop of more than 5% is not allowed at the end of the test. The test results are entered in the passport.
the bridge was destroyed and rebuilt three times. Last time it was undermined by the Germans during their retreat in 1944 with the expectation of complete destruction. The explosion in one of the middle panels of the arch was completely broken and deformed. The tops of the bulls and the abutments were destroyed. The arches of the navigable span, broken into two semi-arches, turned in the longitudinal and transverse directions during the fall and, having moved from the supports, as if jammed one another. The bridge was rebuilt according to the project and under the supervision of engineer S.T.Sokhransky according to the work flow diagram shown in Fig. 11.2. The lifting of the semi-arches was especially difficult, since they had to be lifted in the longitudinal and transverse directions, aligned the oblique over the supports and moved over them in design position... The right semi-arch was lifted in a combined way using truss lifts attached to the channel end, attached to two tower supports, and at the coastal end - two hundred ton hydraulic jacks on cobblestone cages. The left semi-arch and the surviving part of the coastal superstructures were lifted with the help of jacks and pulleys attached to wooden portals, towers or stone cages. The refurbishment work was completed in seven months with the help of skilled riveters, welders and divers.
2 The blast furnace, blown up within the tuyere zone, sank by 3.5 m and at the same time shifted to the side by 1.5 m, and the difference in the marks of the opposite points of the moratorium ring reached 0.6 m. The mass of the settled structures of the metal casing was 1200 tons. was produced as follows. At first, under the moratorium ring of the blast furnace, five supports from metal pipesthat have taken the load of the furnace. Then the lining was dismantled. The blast furnace was secured with six braces, and the descending gas pipelines were suspended from the masts. Subsequently, the temporary supports were removed, and the mass of the furnace was taken up by lifting devices. The oven was lifted and leveled by three separate banks of five hydraulic jacks with a lifting capacity of 200 tons each. To recharge the jacks, two types of metal packages were used: from rails with a height of 140 mm for busting after one pumping out of the jacks and beam 800 mm from pipes to replace 5-6 cages from rail packages. First, one-sided lifting of the blast furnace was carried out on two supports by rotating it in.
For hydraulic jacks, by the end of the test, the pressure drop should not exceed 5%.
Walkways consist of metal sleds, gutters, mechanical (hydraulic) jacks and racks. The chute is designed to facilitate the ejection of pipes onto the walkway. To reduce the coefficient of friction when moving the pipe along the chute, it is recommended to cover the bottom of the chute with a slippery coating (slippery plastic).
Currently, all newly commissioned wells are equipped with reinforced concrete platforms for mobile units, as well as wellhead platforms and bridges made of reinforced concrete slabs. Preparatory work much easier with the use of movable walkways. Walkways with a gutter (Fig. 24) consist of a transport sled 1, platform 2, gutter 5, mechanical or hydraulic jacks and a set of racks 3. The design allows you to change the slope of the gutter and racks 4. During transportation, the platform is dismantled and placed in a sled.
the locking pawl is retracted in the ratchets, and the non-return valve in the hydraulic jacks opens.
5.1.3. The controls for the lifting and lowering operations of the unit should be concentrated on an independent panel equipped with the necessary control and measuring instruments, located in a safe place and providing visibility of the tower, mast, hydraulic jacks, winches and other mechanisms installed on the unit.
Prestressed concrete is especially widely used in the construction of bridges, as well as in the construction of structures calculated according to the theory of plasticity. A steel wire reinforcement strand wrapped in a steel sheet or plastic sheath is cast with concrete in the same way as the reinforcement. The ends of the strands or bundles are terminated on the main plates in such a way that the prestressed concrete hoists can be pulled to the stops by hydraulic jacks even before the structural elements are loaded.
