Welcome to vulcanhammer.info, the site about Vulcan Iron Works, which manufactured the durable air/steam line of pile driving equipment for more than a century. Many of its products are still in service today, providing reliable performance all over the world. There’s a lot here, use the search box below if you’re having trouble finding something.
Vulcan’s success with the 80C lead its customers to ask the same question they asked about the 08: could a larger hammer be fit in the frame. In the case of the 08, there was already the 0R and 010, and the 012, 508, 510 and 512 were to come. As was the case with the 65C, Vulcan simply put a false head on the top to increase the weight needed to keep the hammer in place due to the increased pressure. The result was the 85C and the 100C. General arrangements are below.
The Vulcan 80C was the Super-Vulcan counterpart to the Warrington-Vulcan 08, and was one of the more successful differential-acting hammer sizes Vulcan produced.
Specifications are below.
Bulletin 70F Specifications
Bulletin 70D Specifications
Bulletin 70A Specifications
Some photos, job and shop, are shown below.
Vulcan 80C cable hammer, S/N GH-1070, taken 17 January 1979 at the Chattanooga plant. Vulcan was relatively late in the life of the product line in putting cables on the differential-acting hammers, and when it did the “pockets” (which you can see on either side of the cylinder just below the steam chest) made it impossible to jack the cables. Both Raymond and Pile Hammer Equipment had better methods of cabling the Super-Vulcan hammers.
Vulcan 80C hammer driving 55′ long 12″ concrete piles for the Bay Area Municipal Utilities District Sewage Treatment Plant in Oakland, California; H.F Lauritzen Company was the contractor. This is a good example of a fixed leader arrangement, which offers the best support for hammer and pile alike. This is especially important for concrete piles.
Some general arrangements, Chicago and Chattanooga, are shown below.
It’s evident that Vulcan had some difficulty in getting the right combination of economy, operating pressure and configuration with its 65C and 65CA hammers. Did Raymond, which made many of its own designs of Vulcan style hammers, do any better?
Based on its experience with the Vulcan differential hammers, Raymond designed several differential-acting hammers, including its own 80C, the 150C, and this hammer. A general frontal view is shown at the right; a photo of one in Vulcan’s yard is above. Raymond made several interesting changes in the hammer design:
Different sheave had design.
Raymond configured the hammer for 120 psi operating pressure, which was one of Vulcan’s original proposals (the Raymond probably antedates the Vulcan 65C.)
Coil springs (later rubber springs) at the top for the hammer extension, or sled, which Raymond always used with its leaders.
Male jaws to mate the hammer with the extension (Vulcan later used male jaws for its offshore hammers.)
Cables from head to base. Raymond used a tapered bottom fitting; machining the mating tapered holes in the base was tricky and expensive, as Vulcan found out the hard way when it machined a base for the single-acting Raymond 1-S.
Draw bar for the slide bar instead of the hammered keys.
Baffle in the cylinder for the exhaust; the ports for exhaust were probably higher than for any other Raymond or Vulcan hammer.
Steam chest bushing, which Vulcan adapted and improved upon as a removable liner.
Lighter, dished-out pistons for the piston rod. (Why weight reduction was necessary for a striking part component isn’t quite clear…)
Vulcan acquired a great deal of Raymond engineering and inventory when Raymond finally fell apart in the early 1990’s, and was in the process of incorporating many of Raymond’s changes in its own product line when the company was merged in 1996.
Specifications for the Raymond 65C are shown below.
The 65C is the counterpart to the Warrington-Vulcan 06 hammer. Upsizing single-acting hammers is a fairly straightforward process as long as the frame is capable of withstanding the load. Doing the same thing with differential-acting hammers such as the 50C is an entirely different matter, as the 65C shows.
Specifications are on the general arrangement above and are also shown below.
Vulcan eventually addressed these issues with the 65CA; the ad for it from Onshore Tip 61 is shown below.
Like its Warrington-Vulcan counterpart, the #1, the 50C was a popular hammer and, along with the 80C, comprised a large block of Vulcan’s production of these hammers. Specifications are below.
Bulletin 70A Specifications
Bulletin 70D Specifications
Bulletin 70F Specifications
Some general arrangements are below. Note that the hammer in the image above sports a bar-type head while these have a sheave-type head; this is explained here.
Some photos are below.
Vulcan 50C hammer, installing sheet piling, Chicago, 1974. Note the yellow Decelflo muffler on top of the hammer; this was one of the first uses of the exhaust muffler.
Vulcan 50C driving piles on a batter using swinging leaders, Hudson, OH. Swinging leaders are usually used to drive plumb piles, but in this case the leaders are stabbed in the ground so that the whole assembly can be leaned back. It’s done but requires considerable skill on the part of the contractor.
Vulcan 50C, driving sheet piling. Vulcan hammers weren’t known to be sheet pile specialists but, as these photos show, they got the job done anyway. As was the case before, an “offshore” type leader was used, where a stub leader was hung from a crane and lowered with the hammer. This is good when the pile is supported at the ground, either by a template or in this case other sheet piles.
A concept for the muffler: mount it directly on the back of the hammer, using a bracket integral to the hammer. A special cylinder head would transmit the air from the exhaust to the muffler. Unfortunately the Decelflo program didn’t get far enough for Vulcan to try this concept.
Vulcan 50C hammer with a two-cable arrangement and 26″ jaws, Chattanooga facility, 16 August 1968. The cable arrangement is similar to the one Vulcan adopted on the offshore hammers. Although it required the use of 26″ jaws, it was surely superior to the “pocket” cables Vulcan adopted about ten years later.
The general arrangements are interesting not just for the 30C but to explain features and variants in the Vulcan product line.
The bar head type 30C shows the way the cushion, driving accessory and top plate mate to the hammer.
The bar type head was easy to connect with the leaders, but did not allow for the mechanical advantage of the sheave. It fell out of favour with the onshore hammers, but came back (with its variant, the suspension head) to be standard with the offshore hammers.
The sheave type head, standard with Vulcan onshore hammers. Frequently, however, contractors will remove the sheave and lift the hammer with the sheave pin, negating the mechanical advantage of the sheave.
The #4, another one of the early Warrington-Vulcan hammers, was the smallest one designed and produced. It was referred to as the “Fish Stake” hammer, because, as Vulcan’s literature explained, it was “used for driving fish stakes for pond nets along the shore and in connection with sheeting cap, for small wooden sheeting.”
Specifications for this hammer are below.
It’s interesting to note that the #4 only had upper rubber bumpers; there were no rubber bumpers on the base. This arrangement was eventually incorporated into the very late Warrington-Vulcan hammers, especially the 5′ stroke hammers like the 506 and 512, in order to strengthen the base.
As was the case before valve liners, the shifting of the cylinder cores necessitated valve settings for each hammer. This was also true of the #4; an example of this for a contractor in Walkerville, Ontario is shown below. Walkerville was built as a “model town” around the Canadian Club whisky distillery. Given the propensity of the owning family for whisky, some return on the investment was appropriate.
“C.V.A.” is Campbell V. Adams, Vulcan’s engineer for many years and the designer of the Super-Vulcan hammers.
Here we link to the operations manual (or “Certificate” as the Russians referred to it.) We trust that you will find this informative as to the operation of this concrete pile cutter, which (to our knowledge) has not been duplicated elsewhere.
The Foster hammers are an interesting part of Vulcan’s last years. The concept was to produce a vibratory hammer under a “private label” arrangement, a novelty for the pile driving equipment industry at the time (although the “Chimag” diesel hammers were a similar concept.) In the early 1990’s Vulcan produced several vibratory hammers for the sheet pile supplier L.B. Foster, merging Foster’s own exciter technology (which was Japanese in origin) with Vulcan’s power pack improvements after parting ways with HPSI.
The purpose of this article, however, is primarily to discuss hydraulic vibratory hammers with an emphasis on the “hydraulic.” Pile driving equipment in general and vibratory pile driving equipment in particular poses challenges for the equipment designer and manufacturer. The emphasis here will be on the hydraulics, which are in some ways typical of mobile hydraulics and in some ways unusual. We will use the Foster 4200–the largest of the hammers Vulcan produced–as an example.
Basics of Fluid Power
Fluid power is an important component of power transmission for many mechanical applications. Broadly fluid power can be broken down into two parts: industrial and mobile applications. The emphasis here will be on the latter. Most construction machinery manufactured today has some hydraulic control or power included in the equipment. The original vibratory hammers, designed and produced in the then Soviet Union, were electric, but with the introduction of hydraulic vibratory drivers in the 1960’s today most are hydraulic.
The concept behind fluid power is simple:
A flow of fluid is pressurised.
The fluid is delivered to where it is needed.
The fluid does its work, and is depressurised in the process.
The fluid, at or near atmospheric pressure, returns to where it is pressurised.
The process is repeated.
Since the hydraulic fluid being used (petroleum-based, plant-based, or even water) is virtually incompressible, considerations such as occupy students of thermodynamics are not an issue here, although they appear in other parts of the hydraulic system. The power being delivered at any point by a fluid power system is the product of pressure and flow, thus
where is the horsepower being delivered by the fluid, is the gauge pressure of the fluid in pounds per square inch, and is the flow rate in U.S. gallons per minute.
Both the flow and pressure of the fluid are generally delivered by pumps. Fluid power is a little different from many pumping applications in that the pumps are almost always positive displacement, to insure the accuracy of the flow and pressure. The pump performs the first step of the process outlined above; if the power is transmitted at the other end in a rotary way, a motor performs the third step. Unsurprisingly hydraulic pumps and motors are basically mirror images of each other; their construction is similar (not necessarily identical) and their operation is similar. There are several types of hydraulic pumps and motors in use; we’ll concentrate on piston motors and pumps for two reasons:
These are what were used in the Foster 4200 and all of Vulcan’s high pressure machinery (more about pressure levels later.)
They’re a little easier to visualise if you’re not familiar with the application.
Let’s look at a cutaway pump/motor.
The large bronze barrel in the centre of the motor has a series of holes in a radial pattern, into which the pistons (those small cylinders with the rounded left ends) are inserted. The plate an an angle to the bronze barrel is the swash plate, which (through the other plates) either drives (motor) or is driven by (pump) the spline at the left end of the motor, which connects to whatever the motor is driving or the pump is being driven by. The angle between the barrel and the swash plate alows the pistons to move in the barrel, much like the pistons in an automobile do. The displacement per piston is given by
where is the displacement of each piston in cu.in., is the cross-sectional area of the piston in sq.in., and is the stroke of the piston in the barrel in inches. The total displacement per revolution of the barrel is obviously
where is the total displacement in one revolution in cu.in./revolution and is the number of pistons.
The flow of the pump or motor is given by
where is the rotational speed of the motor is revolutions/minute. The horsepower output of the motor (or input of the pump) was given earlier. The torque of the motor/pump is
where is the torque of the motor or pump in foot-pounds.
The simplest configuration of a pump or motor is a fixed-displacement. In this the angle between the barrel and the drive spline (or keyway) is fixed and thus the stroke is fixed. This precise flow is an important aspect of fluid power systems, as it regulates the speed of the load, which can be rotational or translational.
However, there are good reasons for varying the displacement–and thus the flow output–of a hydraulic pump. The pump shown above has a mechanism on the right which varies the position of the right end of the barrel, and thus the displacement of the pistons. Although it’s possible to vary this control manually, the mechanism shown does so by measuring the pressure of the hydraulic fluid, and thus is referred to as pressure-compensated. We’ll come back to why that’s important later.
One further thing that complicates the equations above is leakage around the pistons. Because of the speed of their movement, most piston pumps and motors–and for that matter most hydraulic motors, pumps and valves–do not use seals in them, but tightly fit the pistons or valve spools to the barrel or valve body and allow some leakage. Although this may seem inefficient, the small oil flow allows for lubrication of the components and cooling of the pumps and motors without the drag that seals would induce. This reduces the flow available for power transmission, and the ratio of the ideal flow to the flow actually available after leakage is referred to as volumetric efficiency. This can vary for a number of reasons, but for piston motors and pumps such as we are dealing with here a volumetric efficiency of 90% is a good estimate.
The exciter does the work of the system by inducing a vertical, sinusoidal force in the pile, which sinks by its own weight. The eccentrics producing this force are turned by a motor, which is driven by a pump on the power pack through the hoses. The pump in turn is driven by a diesel engine, which is the prime mover of the system. There’s also a clamp to hold the driver to the pile; in reality there are two hydraulic systems, one for the motor and one for the clamp. This allows us to illustrate hydraulic systems with both rotational output (the motor) and translational output through a cylinder (the clamp.)
The 4200 has two motors to drive its eight (8) eccentrics, but in this case only one clamp for sheeting. A hose layout for the exciter is shown below.
The supply hose is the hose which carries the pressurised oil to the motors. The return hose carries the depressurised oil back to the power pack. The case drain hose returns the leakage from the motor (see earlier comments on volumetric efficiency) back to the power pack. In some cases the return hose can be used as a case drain hose, but in this application there is too much back pressure. The two clamp hoses are bi-directional, as we will discuss shortly.
Until 1991 Vulcan purchased its power packs from HPSI, which used an air-over-hydraulic control system. In going to electric-over-hydraulic, Vulcan was more in line with its competition such as ICE and APE.
Older hydraulic systems used several types of transmissions between engine and pumps, including power-take-off (PTO) drives. Vulcan used a direct drive which was basically a thin circular plate which transmitted torque from the engine to the pump shaft. This seriously reduced mechanical inefficiencies in the system.
We can thus see the essential components of the hydraulic system:
Prime mover (4).
Pump to pressurise the oil (6,7)
Equipment to do the work and depressurise the soil (motors, clamp)
Cooling and oil storage (1,15) after oil is returned to the power system.
Pressure in Hydraulic Systems
Fluid power systems are designed to deliver an oil flow at a given flow rate. So what pressure does this come at? This is a key point in fluid power systems: pressure is determined, without any other restrictions, by the load itself. This is true whether the load is rotational or translational, and in this system we have both.
Rotational (Motor) Loads
The main pump (6) is configured to, at maximum displacement, deliver a given flow of oil. This in turn determines the rotational speed of the motor. The power put into the system–a product of the pressure and the flow–varies with the load of the system, and that in turn varies with the pressure. So are there limits to that pressure?
The answer is obviously yes. Hydraulic systems, broadly, divide themselves into two pressure ranges: high and low. Low pressure systems generally have their pressure limited to about 2500-3000 psi, and a wide range of hydraulic systems operate in this range. High pressure systems run around 5000 psi and beyond. Each system has its own standard of components. The Foster 4200, in common with Vulcan’s 2300 and 4600 vibratory drivers, was a high pressure unit.
So how do we limit the pressure? In “classic” systems such as the HPSI power packs Vulcan started with, there was a fixed displacement pump and a relief valve (11). When the pressure reached the system maximum, the hammer would slow down and the excess oil would “dump over relief.” This worked, but it generates a lot of heat, which means that the system’s thermal protection shuts it down in short order.
On this hammer, Vulcan used a pressure-compensated, “load-sense” system, which required a special relief valve which, in turn, informed the pump that maximum pressure had been achieved. The pump would reduce its displacement as described earlier until the flow and pressure were balanced. There was still a relief “just in case” for safety purposes, but much of the dumping over relief was eliminated. This also enabled the operator to slow the hammer down without slowing the engine down, allowing the engine to operate in its best torque range.
Translational (Cylinder/Clamp) Loads
Before we describe the hydraulics, let’s look at what the clamp does. Some types of hydraulic clamps are shown below (from this article.)
Fun fact: Foster started this project using the clamp type (c), which they inherited from the Japanese. This clamp was common when cylinders were not large and the lever action was needed to obtain the force, but these clamps were heavy. Vulcan convinced them to convert to type (b), albeit without the accumulator, which had been a U.S. industry standard for a long time. Vulcan also convinced Foster to adapt an integral clamp cylinder as opposed to the bolt-on types which are still common on American vibratory equipment.
The clamp is simple: the clamp in pressure is applied to the large (head) end of the clamp and the jaws close on the pile, clamping the pile and stopping the cylinder. When driving is finished, pressure is applied to the small (rod) end of the clamp and the jaws open. The speed of the movement either way is computed as follows:
where is the velocity of the clamp in in/min and is the area (head or rod) under pressure, sq.in. Moving cylinders is a common hydraulic operation, one (with the right control system) can be done with great precision. In this case positional precision wasn’t a big deal; the clamp cylinder just needs to go until the pile stops it.
So what happens then? The system “deadheads,” and, with a fixed displacement pump, most everything goes over relief, with the usual heating problems. There are ways of getting around that but here again pressure-compensated pumps are the best answer, going to nearly zero flow when the clamp deadheads.
Another fun fact: In adopting Vulcan’s clamp design, Foster also incorporated Vulcan’s safety check valve in the clamp, which continued pressurisation in the event the clamp hose was cut. Foster also incorporated Vulcan’s interlock that made it impossible to start the hammer until the exciter was clamped to the pile. That’s one reason why a separate hydraulic system is needed for the clamp; another is that full clamp force and pressure is guaranteed, whereas with the pump for the motor the pressure varies.
We’ve covered a lot of ground here. Hopefully you’ve gotten a better idea of what hydraulic systems in general–using a real-life application–are all about. Vulcan’s effort with Foster’s vibratory hammers was a unique one, and probably resulted in the best vibratory driver (if not the most economical to produce) Vulcan ever made.