With the continuous advancement of industrial production, the lifting machinery in many enterprise factories has entered the stage of “old age”. Equipment with a service life of about 15 years often faces problems such as aging of electrical components and mechanical wear, which not only leads to a high on-site failure rate, seriously affects production efficiency, and may even cause vicious safety accidents such as hook pressure. At this time, the old equipment is systematically carried outCrane safety protectionUpgrading and technological transformation have become the top priority for safe production of enterprises.
For the different working environments of indoor bridge cranes (cranes) and open-air gantry cranes (gantry cranes), the focus of safety protection and the transformation plan are also very different.
1. Focus on “anti-fall and anti-pressure people”: special transformation of hook safety protection
If there has been a hook safety accident on the equipment, it means that there is a vulnerability in the intrinsically safe defense network of the lifting mechanism, and targeted transformation must be given priority.：
- Upgrade the lifting brake system (brake): 15-year-old brakes are prone to spring fatigue or aging of hydraulic push rods. It must be completely replaced with a new type of electric hydraulic block brake. For equipment that is frequently fully loaded, it is recommended to install a low-speed shaft safety brake on the large gear ring of the reel to achieve a “double brake” guarantee to prevent the hook from falling out of control due to the broken shaft of the reducer.
- Install two-stage limit protection: Eliminate a single fire-breaking stopper and transform it into a ”fire-breaking switch + hammer-type stopper" or a double-limit protection for rotary encoders. When the first limit fails, the second hard limit can forcibly cut off the total power supply to prevent the hook from rushing to the top and breaking the rope.
- Add intelligent sound and light warning and safety light curtain: Install an area laser/infrared safety light curtain under the hook or around the cart. As long as the crane is activated or the hook moves up and down, a high-decibel sound and light warning will be issued on site; once someone is detected in a specific hazardous area under the hook, the system will automatically power off and lock the brakes to actively prevent pressure accidents.
- Promote ground wireless remote control operation: Transform the old blind area operation of the cab into an industrial wireless remote control operation, allowing the operator to stand at the best and safest angle of sight for hoisting.
2. Solve the “high failure rate”: the control system and power supply are fully upgraded
Frequent failures will seriously drag down production progress. Most of the failures of old cranes are concentrated on contactor burning, motor overheating and poor line contact.
- Frequency conversion transformation of the whole vehicle control system: Completely eliminate the traditional cam controller or AC contactor speed regulation, and replace it with a fully frequency conversion control system of “PLC +inverter”. The “soft start” function after the frequency conversion transformation can make the starting and braking extremely stable, eliminate mechanical shocks, reduce the failure rate of the electronic control system by more than 90%, and greatly extend the life of the reducer and steel structure.
- Update slip line and drag chain cable: Replace the old angle steel sliding wire and adopt seamless safety sliding contact wire to solve the frequent power outages caused by poor contact. The power supply of the trolley has been completely changed to a cable towline system to prevent the cable skin from cracking and short-circuiting in outdoor or indoor high temperature environments.
3. Adapt to local conditions: differentiated configuration of indoor and outdoor crane safety protection
- Key points of transformation of open-air gantry crane (gantry crane):The core is windproof, anti-overturning and lightning protection. The old manual rail clamp should be transformed into a fully automatic hydraulic rail clamp or iron shoe, and electrically interlock with the cart operating mechanism; a high-precision digital anemometer should be installed to automatically cut off the walking power supply when the wind speed exceeds the standard; at the same time, the lightning protection grounding system must be improved (the grounding resistance is less than 4 ohms).), and install a rain cover for the outdoor motor.
- Key points of transformation of indoor bridge crane (crane):The core is precise limit and anti-collision. It is necessary to install a lidar ranging anti-collision system to realize two-stage anti-collision protection for long-distance deceleration and close-range parking when multiple vehicles are running in a factory building.
4. Reminder of the "red line” of the transformation of old equipment over the past 15 years
Before investing funds in electrical and protective equipment retrofits, companies must clarify one item.Crane safety protectionThe hard and fast indicator of "one vote rejection”——Steel structure life and defect assessment.
The design life of general purpose cranes is usually 15 to 20 years. Before the renovation, a qualified third-party institution or special inspection institute must be requested to perform metal flaw detection on the main beam and outriggers. If it is detected that the steel structure of the main beam has developed fatigue cracks that cannot be repaired, or the deflection under the main beam seriously exceeds the standard, the equipment has lost its transformation value and must be forcibly scrapped and replaced with a new machine in accordance with the law.
In addition, lifting machinery belongs to special equipment. Before the renovation and construction, it must be notified to the local market supervision and administration department for construction. After the renovation is completed, it must pass the supervision and inspection of the Special Inspection Institute and obtain a new special equipment use registration certificate before it can be put into production. Through scientific and consistent technological transformation, improveCrane safety protectionIn order to truly protect the safety and efficiency of the enterprise, the system can truly protect the safety and efficiency of the enterprise.
