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Using Directional Control Valves

Directional control valves are the workhorses heavily relied upon in the worlds of hydraulic circuits and machinery as well as pneumatic systems because of the way they allow fluids to flow into specific pathways from one or multiple sources. The most basic configuration is a spool inside a cylinder where the movement of the spool is what permits or restricts the flow of fluids through it. An actuating force must be applied to operate the valve and move it from normal (or neutral) position to working position. More complex control valves can have more than two basic positions by have multiple working positions.

Types of Directional Control Valves

Directional control valves are classified according to their various characteristics, such as the number of ports (external openings allowing fluid to enter and leave the valve), number of positions, actuating method used, the type of spool, the fluid path, and so on as follows:
  • Fluid Path: Check valves (allows flow in one direction only actuated by low-pressure input flow, blocking flow in the opposite direction), shuttle valves (allow for switching back and for the between two flow sources into a one-branch circuit, where one source is often just a backup for the other), two-way valves, three-way valves, four-way valves.
  • Positions: There are typically two or three positions – neutral/normal and one or two working positions.
  • Ports: The number of openings through which fluid can flow into and out of the valve.
  • Actuation: How the valve is moved from one position to another, including manual (moving a handle, pushing a button, stepping on a foot pedal), mechanical (cam and rollers), pilot signal (hydraulic or pneumatic) or solenoid (energizing the solenoid or electric coil creates a magnetic field against the armature to push the spool into position.
  • Spool: The type of spool can rotary (typically with manual actuation) such that the spool is rotated into a working position or sliding such that the spool is slid into a position to align its various chambers with the ports.

Functionality of Directional Control Valves

Out in the field these devices are often nicknamed “bang-bang valves.” These valves can shift from fully open to fully closed in an instant, which can cause “fluid hammer” or a banging noise. Sometimes they’re also called “discrete valves” because they shift from one discrete position to another or “switch valves” because they switch the flow by stopping it, starting or changing its direction. A number of combinations are possible in terms of the mix of ports and positions of different directional control valves. One example is a 4/3 or 4-ports 3-position valve. In the US it would be called a 4-way valve, but international standards use the word “port.” One of the ports would be for receiving a pressurized fluid from a pump, another would route fluid back to the reservoir or exhaust system (for pneumatic systems), and the remaining two ports would be for routing fluid to and from the actuator. In terms of the three positions, neutral would mean all ports are blocked and there is no flow of fluids. The remaining two working positions allow for the flow of liquids in the right directions to reach various components.

   

Directional Control Valve

Industries that Use Directional Control Valves

Using directional control valves is absolutely essential to any industry that relies on hydraulic circuits, machinery and equipment, which covers a dizzying array of application. Anything with a motor is going to use directional control valves, so they figure prominently in the automotive industry in every vehicle transmission you can think of, including automatic transmissions (AT), automated manual transmissions (AMT), continuous variable automatic transmissions (CVT), double-clutch transmissions (DCT) and the control of automated clutch actuations in hybrid drives. It’s hard to think of anything “industrial” that doesn’t make use of directional control valves – die casting and foundry, machine tooling, marine/offshore, press, primary metals, plastics, pulp and paper, test equipment and simulation, turbine control (wind, steam, water), wood processing and much, much more.

Importance of Sourcing Directional Control Valves

Given how widely used directional control valves are across vastly different industries and applications, there are innumerable choices of valves from many different manufacturers. It makes sense to turn to a manufacturer that specializes in valves for your specific application. Metro Hydraulics designs and manufactures hydraulic valves for the agricultural, construction, turf and light industrial equipment markets. Valve types include 1, 2 and 3 spool directional control valves; two-position selector valves, lock valves, check valves, restrictor and relief valves all in a variety of sizes. If our standard valves don’t quite match up to what you need, we’ll gladly customize a design to meet your specifications.

At Metro Hydraulic, we’ve been engineering the design, manufacturing and marketing of directional control valves for more than five decades. Contact Metro to request a quote today!

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Deciding Between Bottle Jacks and Floor Jacks

For any job, in any industry, choosing the right tools to work with is crucial for ensuring smooth, efficient, and safe operations. In the automotive industry, professional and amateur mechanics alike often struggle with determining whether to use a floor jack or a bottle jack for repairs. One offers stability, ease of use, and high speed, while the other provides optimal power and a compact size.

Floor Jacks

Floor jacks are oriented with the hydraulic cylinder positioned horizontally. One of the most obvious advantages of floor jacks is their portability; unlike bottle jacks, most floor jacks have casters that allow for easy rolling back and forth, so jacks can be repositioned on the fly. Unfortunately, they are also somewhat bulky and unwieldy, which can be a drawback when space is at a premium.

Another advantage of floor jacks is that they sit low to the ground. This means they can be easily rolled under vehicles that also sit low. There are even specialized low-clearance jacks available for extremely low cars. And because floor jacks are designed with a long pump handle that allows for very quick lifting and lowering of cars, speedy operations are possible. The long handle also makes for easier use, an advantage for workers concerned about being able to operate jacks quickly in a pinch.

While providing the same power as a bottle jack, floor jacks do take up a lot of floor space. They usually require quite a bit more maneuvering to set up in a way that the handle can be properly utilized. They also require more storage space. And because of their horizontal design, floor jacks can hoist much less weight than bottle jacks.

Bottle Jacks

Bottle jacks, on the other hand, are mounted vertically, and the more straightforward design allows them to lift more weight to higher elevations. These jacks are also smaller and more easily stored than floor jacks, as well as significantly cheaper.

Truck owners, in particular, might find bottle jacks an ideal solution, as clearance is generally not an issue and easy storage is possible in a cab compartment. This portability also makes bottle jacks especially useful in an emergency, as they can be easily carried to the scene.

Compared to floor jacks, however, bottle jacks cannot offer high stability due to their narrow frame; floor jacks provide a more solid solution for tricky operations. Bottle jacks also have a minimum lift height, which may pose problems when working with standard-clearance automobiles.

Learn More

Bottle jacks and floor jacks offer distinct features and advantages, and each type is well-suited to a range of different automotive applications. These two types of jacks can sometimes even be put to good use in combination with one another. For example, when changing suspension components, it may be helpful to employ a floor jack to boost the vehicle and a bottle jack to keep the suspension isolated to one side of the vehicle.

To learn more about the differences between bottle and floor jacks, contact the team at Metro Hydraulic Jack Co. today. As a leading service provider and distributor of industrial jacks, we can walk you through the selection process and ensure you get the best solution for your unique needs.

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Hydraulic and Mechanical Jacks in the Construction Industry

A jack is a versatile tool that uses force to lift heavy loads. Screw threads and hydraulic cylinders are the primary mechanisms with which force is applied; therefore, jacks fall under the categories of mechanical or hydraulic.

House Jacks

Mechanical jacks, such as car jacks and house jacks, hoist heavy equipment and are rated on lift capacity. Hydraulic jacks, on the other hand, tend to be stronger and can hoist heavier loads higher. These types include bottle jacks and floor jacks.

Both mechanical and hydraulic jacks are used in countless industries, including the automotive, shipping, mining, waste removal, and retail sectors. Jacks are also commonly utilized in construction applications to lift heavy equipment and support or lift a building during renovation or relocation.

Mechanical Jacks in Construction

Often found in automotive garages, mechanical jacks use physical means to raise and lower loads, which typically range from 1.5 tons to 3 tons. A screw jack is a common type of mechanical jack, which works via a motor or lever cranked by an operator. A screw uses the shape of its threads to raise or lower the load, or a traveling nut does the lifting while the screw turns in place. Mechanical jacks are self-locking, which means that when power is removed from the jack, the screw stays in place until power resumes. This setup makes mechanical jacks safer than their hydraulic counterparts, because users don’t have to fear a loss of power.

Mechanical jacks are used to change stage designs, alter settings on woodworking machines, and adjust radio telescopes. In the construction industry, screw jacks — also called house jacks — are used to hoist buildings from their foundations for repair or relocation. In these applications, multiple jacks are utilized, and wood cribbing temporarily supports the structure until the desired lift is reached. Screw jacks can also be used for raising older beams or installing new ones.

Hydraulic Jacks in Construction

Hydraulic Jacks in Bridge Construction

Hydraulic jacks, predictably, use hydraulic fluid as their main power source. They consist of a pair of cylinders of different sizes connected by a pipe and hydraulic fluid or oil. The hydraulic fluid is forced into the cylinder of the jack via a pump plunger. When the plunger pulls back, oil goes from the reservoir into the pump chamber. When the plunger moves forward, the oil is propelled into the cylinder. This oil movement builds up pressure in the cylinder, and that pressure powers the jack.

The two most common types of hydraulic jacks are bottle jacks and floor jacks. Bottle jacks, also called hand jacks, are portable. The piston is positioned vertically, and it supports a bearing pad that touches the object being lifted. They’re most commonly used to lift cars, but they can also be used in the medical industry as hydraulic stretchers and patient lifts. Hydraulic jacks also can be utilized as pipe benders and cable splicers.

In floor jacks, also known as trolley jacks, the piston is in a horizontal position, and a long arm provides vertical motion to a lifting pad. There also are wheels and castors included in their build. In the construction arena, hydraulic jacks are used for lifting equipment and vehicles such as bulldozers, forklifts, trolleys, trailers, and excavators. These versatile jacks can also lift elevators in low- and medium-rise buildings.

Supplying the Construction Industry for Decades

For nearly 80 years, Metro Hydraulic Jack Co. has been a leading distributor and service provider for industrial hydraulic equipment, jacks, tools, parts, and lubrication equipment, and we’re proud to offer top-quality mechanical and hydraulic jacks for customers across a wide range of industries.

Request a quote today to learn how we can help with your specific lifting needs.

 

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Why is Safety Important?

In the construction industry, safety is always a relevant issue. Although the industry has taken steps to promote a greater awareness of the importance of safety in the workplace, accidents still occur. Some of these accidents are preventable, which is why it is important to educate industry members about safe practices and procedures regularly. Just recently, in Midtown Manhattan, a woman was struck by a flying buzzsaw from a nearby construction crew. NBC New York reports that the woman sustained a gash on her leg from the 3-foot blade and was taken to a nearby hospital for treatment. Thankfully, the injury was not serious. The incident is a strong reminder that accidents can and will happen, creating serious breaches in safety. In this case, the construction crew had been using the buzzsaw to tear up a roadway to fix an underground water main. Witnesses say that the blade came off the machine and was propelled down the sidewalk by its own force. As a result, workers and bystanders alike were put at harmful risk. To minimize the likelihood of accidents like the one in Manhattan, groups like the Construction Industry Safety Initiative (CISI) and Incident & Injury Free (IIF) Group strive to develop a culture where safety is a core value. Events such as Safety Week 2014, which was held in May, help promote this idea through free organized activities, employee training, and safety performance evaluations. At Metro Hydraulic, we’ve worked hard to encourage a safety culture at our distribution and service centers. We fully support efforts by the construction industry to bring the issue of safety to the forefront of discussion—and on workers’ minds. We hope that these events make a positive difference in the lives of both construction workers and the larger public.
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Building Bridges with Hydraulics

This year, two major bridges in the tri-state area have either begun or planned out major renovations and infrastructure repairs. These include the heavily traveled George Washington Bridge and Pulaski Skyway. Both projects have a budget of $1 billion or more, and require substantial construction. Metro Hydraulic is proud to report that some of this work will be completed with the help of our hydraulic equipment. The George Washington Bridge, an 82-year-old bridge that connects New York and New Jersey, is set to undergo a series of renovations and upgrades over the course of seven years. According to CBS, the planned changes include replacing 592 suspender ropes, repairing the main cables, installing new safety technology, and swapping the necklace lighting our for programmable LED lights. The extensive construction project is slated to begin in 2017 and end in 2024. Like the George Washington Bridge, the Pulaski Skyway is also 82-years-old. It was recently shut down for a reconstruction project that may take about two years. The Pulaski Skyway is often used by riders who travel from New Jersey to New York through the Holland Tunnel. Unfortunately for these commuters, the bridge needs significant renovations to its reinforcing bars, concrete railings, and roadbed, among others. The New York Times reports that the crossing has become “so frayed that the state installed netting to catch the falling debris.” Metro Hydraulic distributes hydraulic equipment to some of the construction companies that work on these projects and other, similar infrastructure repairs. As the tri-state area moves forward with renovations on the George Washington Bridge and Pulaski Skyway, they will rely on our high-quality equipment and timely shipments to get the job done as quickly and efficiently as possible. As a member of the New Jersey community, we look forward to the completion of these exciting renovations!
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Innovations for Hydraulics: Advanced Bridge Construction

One of our main sectors of business here at Metro Hydraulic is within the sphere of construction. There are many different uses of hydraulics in construction, from materials handling, to jacks and pullers, and other applications for transport of materials and work pieces. One of the coolest innovations we’ve seen in construction recently also utilizes hydraulics, and we’re intrigued. This article is a great expo on the new process called “Accelerated bridge construction” or “ABC”, for building highway overpasses and other bridge structures, and explains what we think is a great new process that improves vastly on the old for several reasons. First, it allows traffic to continue to flow while the building process, which takes up the majority of the time of construction, is in progress. This alone is immensely practical solution to the tedious detours associated with most other jobs of this type. The road closure time taken for this particular application was 8 hours – an incredible reduction of time and associated labor costs. The system that makes this possible is a combination of hydraulics and a lubricated sliding surface. The new structure is progressively slid into place along the sliding surfaces, pushed by hydraulic jacks which are incrementally moved as the new platform is slid into place. We’ve seen a lot of great innovation in our experience with construction, and this is no exception. ABC represents a significantly improved process that serves both commuters who use the roadways and construction companies that build them. It’s heartening for us as hydraulic suppliers to see hydraulic systems being used to such great effect for construction. We hope this process continues to be gain acceptance and be further implemented for infrastructure construction and repair everywhere.
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Fall Protection in Construction

It’s a sad fact that the construction industry is a dangerous one. If the proper steps aren’t taken to ensure workers safety, the risk of injury or fatality is high. The Occupational Safety and Health Administration (OSHA) claims 46 hundred construction workers were killed on the job in 2011, which is third lowest annual total in the two decades since the fatal injury census started. The worst thing about this fact is every onsite injury is preventable.

“Falls are among the most common causes of serious work related injuries and deaths,” according to OSHA’s fall protection page. “Employers must set up the work place to prevent employees from falling off of overhead platforms, elevated work stations or into holes in the floor and walls.”

Overhead platforms, elevated work stations, and holes in the floor and walls all pose hazards for workers, and it’s the responsibility of employers to make sure that precautions have been taken to keep workers safe. Once a workers height reaches four feet in general industry workplaces, five feet in shipyards, six feet in the construction industry or eight feet in long shoring operations, OSHA mandates that fall protection measure are taken. This also applies to workers that are above dangerous equipment. Here are employer requirements to prevent falls and other injuries:

  • Guard every floor hole into which a worker can accidentally walk (using a railing and toe-board or a floor hole cover).
  • Provide a guard rail and toe-board around every elevated open sided platform, floor or runway.
  • Regardless of height, if a worker can fall into or onto dangerous machines or equipment (such as a vat of acid or a conveyor belt) employers must provide guardrails and toe-boards to prevent workers from falling and getting injured.
  • Other means of fall protection that may be required on certain jobs include safety and harness and line, safety nets, stair railings and hand rails.
  • Provide working conditions that are free of known dangers.
  • Keep floors in work areas in a clean and, so far as possible, a dry condition.
  • Select and provide required personal protective equipment at no cost to workers.
  • Train workers about job hazards in a language that they can understand.

There are a lot of things for employers to keep track of, but keeping up with OSHA’s high standards is the best way for construction companies to keep their workers safe. These construction dangers can be limited if employers take proactive steps to provide for the safety of their employees. We at Metro Hydraulic encourage you to do your part to make sure your work environment is on par with these regulations. Tweet @MetroHydraulic and tell us your safety stories today!

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What Makes a Jack a Hydraulic Jack?

It’s obvious that we know a thing or two about hydraulic jacks at Metro Hydraulic Jack Co.; they’re the basis of our business. Most people have an idea of what jacks are, but there is a lot that goes into these load bearing tools.

When people think of jacks, most often mechanical jacks would come to mind. This category of jacks most notably covers car jacks as well as house jacks. Hydraulic jacks like bottle jacks and floor jacks on the other hand, are used to lift loads that are even heavier.

Hydraulic jacks use multiple cylinders to create pressure by applying force. By putting force on one cylinder, it will create pressure in all connected cylinders. These jacks will have one cylinder larger than the other to produce a greater force, despite the fact that the same pressure is applied in both cylinders.

Using this method, oil is pushed into the two cylinders by pump plungers. This moves the oil through an external discharge check valve before it reaches the cylinder chamber. The valve on the chamber closes to build pressure in the cylinder.

There are several types hydraulic of jacks used for different applications. Bottle jacks are most popularly used for lifting cars for auto inspections, and floor jacks are used to lift items that need a larger lifting pad. Despite their differences, these, along with other varieties of hydraulic jacks all function with the same basic structure.

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Building NYC’s 2nd Ave. Subway

The New York City subway system is one of the largest mass transit systems in the world, and NYC’s Metropolitan Transit Authority (MTA) is making it bigger. Currently, the MTA is constructing the Second Avenue subway line to accompany the city’s existing trains, but this isn’t the first time this subway line was contemplated.

The Second Ave. subway line was conceived originally, with the idea of an East Side train dating back to the 1920’s. According to Second Avenue Saga the train was originally planned to be built from 1930 to 1935, but was abandoned after the stock market crash of that era. There were several more attempts over the past eight decades that all fell through.The unconstructed train line even getting a nod on AMC’s period-drama “Mad Men.”

According to the MTA website,“The Second Avenue Subway will reduce overcrowding and delays on the Lexington Avenue line (4, 5, and 6 trains), improving travel for both city and suburban commuters, and provide better access to mass transit for residents of the far East Side of Manhattan.” . The project will cost $4.45 billion and is being built in phases. The first phase will provide service between 96th St. and 63rd St. as via a rerouted Q train by December 2016.

Even though the idea for this line came almost a century ago, the construction process is anything but old fashioned. Below is a video from the MTA website that shows a “Milestone” event of a tunnel boring machine breaking through a rock wall east of the Lexington Ave-63rd St. subway station.

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Construction Season Gives Hope To Sandy Victims

Hurricane Sandy devastated the American Northeast last October and people are still feeling the effects.  Now that construction season is kicking into gear, victims of the superstorm can look forward with optimism.

Late spring and summer are the busiest times of the year for construction workers and parts of the eastern coast of New Jersey, along with New York City and the south shore of Long Island are in need of repair. Post-Sandy construction has already aided the construction industry, with employment in the first quarter reaching over 111 thousand, up 1.3 percent from the previous year according to Crain’s New York.

The construction work goes beyond just rebuilding homes and commercial buildings damaged by the storm. The Rockefeller Foundation recently announced that it is investing $100 million in a project that will make the NYC more resilient.

“In this world today we will not be able to predict or prevent every catastrophe, take climate change—extreme weather, raging fires, vicious storms,” Rockefeller Foundation President Judith Rodin said according to the Daily Beast. “That’s where resilience comes in. We can prevent their catastrophic impact much better, by implementing resilience strategies that let us buffer those shocks more effectively.”

The investment will feature such advancements as emergency management learning mechanisms, new water waste systems, innovating ideas for urban housing and land use planning focused on resilience principles.

Constructing homes and commercial buildings, along with making the areas safer is aiding everyone involved. Bringing NY and NJ back to life after the devastating storm over six month ago is rebuilding the construction industry.

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