A power unit is used on all hydraulic elevator equipment types. A standard power unit consists of a tank, pump, motor, control valve, and silencer. The power unit pumps oil to push the piston up. It also allows the oil to return to the tank as the car travels down.
A conventional jack assembly is one installed in the ground. Major components of a conventional jack assembly include:
- Jack head
- Packing and flange
- Protection (if any)
When considering modernization, we will assess the age, condition, and operation of the jack assembly components to determine if a hydraulic jack replacement or upgrade if necessary.
Note: Recent code changes in several states have required or recommended the replacement of jack assemblies installed prior to 1972. Contact us to check if your equipment is affected.
The control valve is the device on hydraulic elevators that controls the oil flow to and from the jack. Hydraulic elevators only perform as well as the control valve. If the flow of oil from the power unit to the jack is erratic, the performance of your elevator will be too. This can cause your elevator to ride rough, bouncy, noisy, and/or level improperly.
There are many makes and models of valves, all of which have fine adjustment pins, filtering screens, and “O” rings prone to wear and tear. Many older style valve components are currently hard to get or obsolete. A poorly maintained or adjusted valve is one of the most common causes of erratic operation on hydraulic elevators.
We will assess the condition of your valves and determine if a rebuild, upgrade, or replacement is necessary. We commonly recommend thyssenkrupp’s patented I-Series® valve. As the industry’s number one selling valve, the pistons in the I-2® and I-3® valves are machined to reduce friction, making the operation of the elevator smoother, quieter, and more consistent. If you’re in need of thyssenkrupp elevator repair, our team can help.
Overspeed/pipe rupture valve
Many older elevators are not equipped with an overspeed valve (OSV), also referred to as a pipe rupture valve. This valve can be designed and adjusted in the field to stop the elevator in the event of an overspeed condition caused by a broken supply line or an abnormally high rate of oil flow between the OSV and the power unit. The OSV will not stop the car from overspeeding due to underground cylinder leaks, and is not a substitute for cylinder replacement or other safety devices. We do recommend one be installed if it doesn’t already exist.
A muffler-type device installed in the oil line of a hydraulic elevator pump is designed to reduce noise produced as oil moves through the line. These units can develop leaks and lose their effectiveness. We can assess your silencer for proper performance and determine if replacement parts are necessary for your hydraulic elevator modernization.
The sling is the basic frame which consists of two stiles, a crosshead, and a bolster or safety plank that supports the platform and cab of an elevator. The platform or floor of the elevator is placed in the sling and supported by brace rods in each corner.
The crosshead is the upper member of the car frame. The stiles are the vertical members of the car sling, with one on each side that fastens the crosshead to the safety plank. The brace rod is a rod extending from the elevator platform. This is framed to another part of the elevator car frame or sling for the purpose of supporting the platform or holding it securely in position. Brace rods are supports for the outer corners of the platform, each of which tie to upper portions of the stile.
The platform isolation is made of rubber or another vibration-absorbing material to reduce the transmission of vibration and noise. These pads are often replaced when modernizing, as new isolation is more resilient and helps to reduce vibration and improve the ride comfort for passengers.
The bolster is the bottom horizontal member of a hydraulic car sling to which the platen plate attaches. The safety plank is the bottom member of a sling for a traction elevator which contains the safety.
Guide shoes are devices mounted on the top and bottom of the elevator sling and slide or roll on the rails to guide the elevator through the hoistway. They are equipped with rollers, liners, and tension springs that are subject to wear and tear. Some older style guide shoes require a poured lead Babbitt shoe, rather than a replacement nylon or neoprene liner.
If guides are not maintained or adjusted properly, your elevator will tend to rock, sway, squeak, or even rumble its way through the hoistway. We will assess your guides’ type and condition and recommend repairs or replacements as required.
A buffer is a device designed to stop a descending car or counterweight beyond its normal limit and to soften the force with which the elevator runs into the pit during an emergency.
A spring buffer is most commonly found on hydraulic elevators or used for elevators with speeds less than 200 feet per minute. These devices are used to cushion the elevator and are almost always located in the elevator pit.
An oil buffer is another type of buffer, and is more commonly found on traction elevators with speeds higher than 200 feet per minute. This type of buffer uses a combination of oil and springs to cushion a descending car or counterweight and are most commonly located in the elevator pit. Because of their location in the pit, buffers have a tendency to be exposed to water and flooding. They require routine cleaning and painting to ensure they maintain their proper performance specifications. Oil buffers also need their oil checked and changed if exposed to flooding.
When planning a hydraulic elevator modernization, our technicians will assess the type and condition of your equipment and recommend if any repairs or elevator replacement parts are required. Contact us to schedule a time for our team to evaluate your equipment.