The mechanical transmission of power (2): Jerker Line Systems

From the 1860s to 1940s, many oil wells were pumped by a technology that originates in a sixteenth-century power transmission system used in the mining industry.

One engine operated up to 45 pumps in different locations, each up to a mile away. Power was transmitted by means of wooden rods or steel cables that moved back and forth, snaking through the landscape.

The system was so efficient that an engine used for pumping an oil well could operate a whole cluster of pump jacks. The technology, which still operates in a handful of small oil fields, could also work with renewable energy sources, and shows great potential for efficient small-scale energy use.

From the 1500s onwards, engineers developed mechanical power transmission and distribution systems that became ever more sophisticated: Stangenkunsten. Networks of pivoted, wooden field-rods conveyed power from waterwheels in the valleys to mining machinery in the mountains over distances of up to 4 km, operating pumps and bellows, hoisting ores, and transporting miners up and down shafts.

Steam engines, which started replacing water wheels from the 1860s onwards, were not dependent on the proximity of a stream or river, and could thus be located close to the mine shaft. This eliminated the need for mechanical power transmission. However, the Stangenkunst did not disappear. On the contrary, the technology became even more popular after, rather than before, the invention of the steam engine.

For one, it found a new application in oil production, initially in the United States but later all over the world. It was in the oil industry that the Stangenkunst reached the pinnacle of its development, and became known as the "jerker line system".

The Canadian Jerker Line System

Right from the start of modern oil production in the late 1850s, the Stangenkunst played an important role. It was first used for pumping oil in Oil Springs, Ontario, Canada. While the oil here was of very good quality, production was marginal. The high cost of operating a steam engine at each was not economically viable. In 1863, only four years after the industry came into production, a solution was found by John Henry Fairbank, who set up a system for the transfer of power from a steam engine to multiple oil pumps.

A Stangenkunst in Oil Springs, Ontario, Canada. Source: Markus Wandel.

The method, which became known as the "Canadian Jerker Line System", was remarkably similar to the Stangenkunsten. Fairbank used wooden rods, which swung back and forth from wooden hangers that were suspended from wooden poles, and connected to wooden pump jacks. He didn’t even bother to apply the more efficient pantograph system developed in the 1590s, but used the original single-rod system. This made sense: it was cheaper to build, and friction was less of a problem since the system aimed at distributing power rather than transferring it long-distance (most oil pumps were within one mile of the central power source).

Subdividing and Distributing Power

There were some differences between the Fairbank method and the pre-industrial Stangenkunsten. Two cranks converted the circular motion of the steam engine’s wheel to a reciprocating motion that moved two parallel wooden rods back and forth, just as in the older systems powered by water wheels. In Fairbank’s model, however, a mechanism was introduced to slow down the revolution speed of the steam engine. It consisted of a leather belt placed between the wheel of the steam engine and the cranks. Another addition was the bull wheel, a cast-iron wheel making back-and-forth quarter turns. It was housed in a timber frame just outside the engine shed.

A bull wheel in Oil Springs, Ontario. Source: "Conservation district study appendix", Oil Heritage Conservation District Plan, The Corporation of the County of Lambton.

The bull wheel allowed the reciprocating motion of the two cranks to be subdivided over a greater number of rod lines. In the picture above, for instance, power is distributed from the steam engine to the bull wheel via the two wooden rods on the lower left side. It is transferred to a double field line which runs diagonally from upper left to lower right (the main line) while a single rod line extends to the centre and back of the picture. Thus, in this case, five rod lines branch off from the central power instead of one or two.

A field wheel in Oil Springs, Ontario. Source: "Conservation district study appendix", Oil Heritage Conservation District Plan, The Corporation of the County of Lambton.

Additional subdivision of power to other field rods (branch lines) could happen further along the main line, by means of a "field wheel" — a similar cast-iron, oscillating wheel in a timber frame. The field wheel was also used for diverting a main rod line 90 degrees, as can be seen in the picture above. Field wheels replaced the "Kunst Kreuzen" or "Engine Crosses" used in pre-industrial Stangenkunsten.

V-shaped wooden assemblies, lying on their sides, were used to make less sharp turns. The point of the V was anchored, and acted as the pivot for the mechanism. When the jerker line pulled on one leg of the V, the lines comes from the other direction were pulled out, too. A similar V-rod placed upright was used to change direction in the vertical plane when the line crossed a hill or valley.

The Pennsylvania Jerker Line System

The Canadian jerker line system spread to other oilfields but was eventually superseded by a more sophisticated system in which steel cables and iron bars replaced wooden rods. The metal rods were usually called "shackle lines". This method was developed in 1879 by Pennsylvania oilman Edward Yates and became known as the "Pennsylvania Jerker Line System".

Pennsylvania jerker line system, Flat Rock, Illinois, US. Source: Old Iron.

The famous Pennsylvania oilfields (home to Rockerfeller’s Standard Oil Company) came into production around the same time as the Ontario oil fields. However, unlike in Canada, steam engines were used to power each well for the first two decades. Oil wells in the Allegheny Plateau had a high initial production, which was followed by a rapid drop off. The incentive for pumping these low production wells after their initial outflow was small, as new fields were continually being discovered and drillers would simply sink a new well.

In the late 1870s, following a decline in oil prices and production per well, economising the oil production process became key to profitability. This drive for efficiency resulted in the adoption of the jerker line system, which made using previously-abandoned wells economically viable again.

Pennsylvania jerker line system, Flat Rock, Illinois, US. Source: Old Iron.

By 1885, the jerker line system was used widely in Pennsylvania (then the largest oil producer in North America). Thereafter, it spread to other US oil fields. By the early twentieth century, the system was used in oil fields around the world. By then, the technology had improved and numerous oil-well supply companies had developed standardised systems that could be purchased in part or whole.

Illustration: a schematic of a Pennsylvania jerker line system, showing both geared power and bandwheel power system. Drawing by Eric S. Elmer. Source: Library of Congress.

While the Canadian jerker line system was reminiscent of the Stangenkunsten operating in pre-industrial times, the Pennsylvania jerker line system looked radically different. The prime mover (mostly a gas engine supplied from a nearby well) operated a "central power" (either geared or bandwheel) which slowed down the engine speed, converted the engine’s rotary motion to reciprocating motion, and distributed power to all the rod lines.

One Engine Powers 45 pumps

A back-and-forth motion was imparted to the rod lines by an "eccentric", placed either above or below the geared or bandwheel power, to which 8 to 15 rod lines were hooked that fanned out in all directions. The eccentric was mounted slightly off-center from the power’s central vertical shaft, with the rod lines attached to the outer slip ring. As the eccentric rotated within the slip ring, the slip ring oscillated, pulling the rod lines. For each rotation of the slip ring, the rod lines completed one full stroke (see the illustration on the right).

Typically, the mechanism produced 12 to 20 oscillations per minute, pulling the attached shackle lines an equal number of times. Depending on the number of wells, up to three eccentrics could be mounted on the central shaft, so that a total of 45 oil wells in different locations could be pumped. (More commonly, however, 10 to 25 pumps were powered as they wanted to limit the amount of temporarily unproductive wells in case of an engine breakdown.)

Implications for Field Layout

These different approaches to subdividing and distributing power led to distinct field layouts. In the Pennsylvania system, all oil pumps in the cluster were directly connected to the central power via jerker lines, which radiated out of the engine shed in all directions:

An axonometric view of the Lockwood Poer (built in 1909), near Warren, Pennsylvania, showing the spatial relationship of machinery to structure inside a typical octagonal power. Drawing by Eric S. Elmer. Source: Library of Congress.

In the Canadian jerker line system, none of the pump jacks were directly connected to the central power. Motion was transferred to the bull wheel and then further subdivided along the main lines using field wheels. As a result, the Pennsylvania jerker line system generally produced web-like patterns, while the Canadian jerker line system usually created linear patterns with dendritic lines.

This can be seen clearly in the James Field in Ontario, which still has both systems still operating. The spider-like systems use metal rods, while the linear systems use wooden rods.

Inventory map of the James field with its well numbers, central powers and additional features. The spider-like systems use metal rods, while the linear systems use wooden rods. Source: "Conservation district study appendix", Oil Heritage Conservation District Plan, The Corporation of the County of Lambton.

A Balanced system

The web-like layout of the Pennsylvania system offered an important advantage. Because a Stangenkunst was always a combination of horizontal and vertical power transmission, gravity delivered part of the power. A water wheel or steam engine had to deliver all the power needed to make the horizontal stroke that pulled the vertical mechanism upwards, but gravity aided the return stroke. In the case of oil pumping, the weight of the grasshopper pump made the return stroke, saving energy.

Pennsylvania jerker line system, Flat Rock, Illinois, US. Source: Old Iron.

This effect was doubled when each well was matched with one in the opposite direction. When the sucker rods in one well raised (the upstroke), those in the opposite well lowered under their own weight (the downstroke), helping raise the rods in the well undergoing the upstroke. In other words, the pumps were powering each other with their own weight. This minimized the load on the engine: the only power required was for overcoming inertia and friction, plus the weight of the oil lifted at each stroke.

Pennsylvania jerker line system, Flat Rock, Illinois, US. Source: Old Iron.

The web-like layout of the Pennsylvania system made balancing loads much easier. At all times, half the dead load of rods and mechanisms in the field was being lifted while the other half descended. The steel rods attached to the eccentric could be hooked to, or unhooked from, shackle lines that were connected to the oil pumps. If one well was disconnected, the well in the opposite direction was removed to maintain balance. If this was not possible, the eccentric rod of the disconnected well was hooked to a counterbalance. Since all pumps were directly connected to the central power, one worker could balance the load of all the wells.

This made it possible for a cluster of about 15 to 30 oil wells to be pumped with almost the same engine capacity required to pump one well. In Surface Machinery and Methods for Oil-Well Pumping (1925), H.C. George writes:

"In the early days of the oil industry, all nonflowing wells were pumped individually "on the beam" by steam engines. This system wasted both labor and power, as each well required a man and a steam power plant. At present a group of 15 to 30 similar wells is pumped with a central "power" or "jack" plant with practically the same labor and the same energy capacity as was then used at each well."

"Many oil wells if pumped individually would show a loss, but operated as members of a group they show a profit. The older fields of Pennsylvania, Ohio, West Virginia, and Illinois exemplify efficiency in group operation. In Pennsylvania the 59,000 operating oil wells show an average of less than a quarter of a barrel production per well per day, yet are being operated at a profit by the group method."

"Wells of like characteristics, such as pumping time, length of stroke, and size of tubing should be balanced for best results. Some oil companies pump wells of like characteristics at the same time, then take those wells off the power and put on other wells of like characteristics. This practice is common in some of the eastern oil fields, where many wells do not pump more than a few hours per week, and where powers handle 15 to 30 wells, each pumped only several hours at a time."

Shacklework

The use of steel cables instead of wooden rods also made it easier to navigate difficult terrain. The Pennsylvania jerker line system made use of a variety of devices to support the lines and change their direction — these were generally called "shacklework". The steel cables were hung from tripods or supported by "friction posts", which were fixed in the ground, or "rocking posts", which were mounted on a pivoting base to allow a rocking motion. "Hold-ups" and "hold-downs" guided the lines up or down, while "butterflies" and "ring swings" allowed them to change direction in order to carry the lines around obstacles.

Pennsylvania jerker line system, Flat Rock, Illinois, US. Source: Old Iron.

A "butterfly" was a triangular wooden or metal frame, which allowed up to 90 degree turns and was reminiscent of the V-rods used in the Canadian and pre-industrial system. A "ring swing" was used for lesser changes in direction and was even simpler. It consisted of three rings: one large ring, attached to a another suitable mounting spot, and two smaller rings attached to the large ring and the shackle line. Pendulums and rockers were sometimes used to make the length of the stroke at the well differ from that imparted to the jerker line at the central power.

Often, the shacklework was made from recycled parts, such as discarded rods or pipes. In 1925, H.C. George wrote that "the power or jack plant, and the machinery, shackle line, and jack are all usually standard and purchased from oil-well supply companies, but the shackle line structures are usually designed and built by the operating oil company. This results in a multiplicity of designs and a variety of material."

In some American towns, shacklework from neighbouring oil fields rocked back and forth over streets and alleys.

Jerker Line Systems Still in Operation

The Pennsylvania jerker line system became the dominant technology used to pump secondary oil wells up till the 1940s, pumping wells up to 3,500 feet deep, and remained in use until the 1960s and 70s. A few installations are stilll running today, or operated until recently. Some of the pictures above and below (there are many more if you follow this link), show the last two oil leases in Flat Rock, Illinois, which used a central power source and rod lines of the Pennsylvania type.

Pennsylvania jerker line system, Flat Rock, Illinois, US. Source: Old Iron.

Each is run with a 35 horse power oil-engine and pumps 10 or 11 wells. The rods rest on wood stakes 15 to 20 feet apart and the power moves the rods about 40 cm back and forth. In some places, the rods are rigged to cross a creek or make a turn and head in a different direction. The systems were photographed in 2003, when they were still operational.

Most remarkable, however, are the central power systems in Oil Springs, Ontario, which have been in operation for 150 years now. Some of these oil fields still make use of the Canadian jerker line system, which was the original technology used to pump oil in the mid-nineteenth century when the fields came into production. Most of the lines on the Fairbank field, and some of the lines on the James field, use wooden rods that operate wooden pump jacks, while some lines on the James field, and all lines on the neighbouring fields, use the original Pennsylvania jerker line system.

Canadian jerker line system, Ontario. Source: Markus Wandel.

While there are obviously sentimental reasons for using nineteenth and early twentieth century technology — the owner of the fields is a great-grandson of John Henry Fairbank, designer of the Canadian jerker line system — the site is not a museum, but a working field that is economically viable. Instead of holding on to the past and trying to recreate a historic oil field, the technology has been continuously improved to maintain its profitability.

More Efficient

One major change in the technology is that steam engines have been replaced by small electric motors, which are cheaper, more efficient and easier to maintain. Most are equipped with reduction gearing, which has made the bulky powerhouse mechanism redundant. Individually-powered pump jacks have replaced the central power system in locations where running a jerker line has failed to be cost-effective, but where the central power system is still in use, it is so because it remains the most efficient and economical.

Stangenkunst in Ontario, Canada. Source: Markus Wandel.

Even the remaining wooden field rods have been improved: metal hangers that once supported the wooden jerker lines have been replaced with nylon rope for ease of maintenance. The wood for jerker lines and pump jacks is not original, of course, since it is exposed to the elements: the rebuilding of wood equipment has been an on-going historic process.

Canadian jerker line system, Ontario. Source: Markus Wandel.

Oil extraction is usually thought to be large in scale and finite in its lifecycle. However, in Oil Springs, it has been conducted on a continuous, small-scale basis since the late 1850s, while all other oil fields from those times have long been pumped dry using much more powerful technology. One cannot help but wonder how the world would have looked like if all oilmen had stuck with nineteenth century technology.

Future Applications

The jerker line system has value, and could be very helpful for those looking for ways to live comfortably life without excessive energy use. The system in the picture below — which still operates today in Oil Springs — is one that any maker could bolt together quickly in no time. With this set-up, one small electric motor could operate four machines in different locations.

Field motor on steel frame with steel jerker rods on the James Field. Source: "Conservation district study appendix", Oil Heritage Conservation District Plan, The Corporation of the County of Lambton.

Why do this instead of powering each device individually? One: you save three electric motors. Two: there is no need to provide batteries or electric outlets at any of the locations. Three: you can balance the system so that one device helps power the other, saving a considerable amount of energy. The electric motor shown above can also be replaced by a windmill, a water wheel, a solar thermal plant, or a stationary bicycle. In these cases, you can distribute mechanical energy without conversion losses.

Although a Stangenkunst or jerker line system can only transfer mechanical energy via reciprocating motion, it has seen a remarkable variety of applications throughout its 450 years of operation: pumping (either oil or water), ventilation (operating bellows), processing ores (operating trip-hammers), and even transporting people and goods up and down shafts (operating man engines and bucket hoists). Reciprocating motion could also be used to operate sawing machines or, using trip-hammers, to forge iron, process food or fibres, or make paper.

Kris De Decker (edited by Deva Lee)

Sources:

"Surface Machinery and Methods for Oil-Well Pumping", H.C. George, Bulletin 224, Bureau of Mines, Department of Interior, 1925.

"Oil Heritage Conservation District Plan Documents", The Corporation of the County of Lambton, 2010.

"Historic American Engineering Record; Addendum to Allegheny National Forest Oil Heritage" (PDF), HAER No. PA-436, Michael W. Caplinger, 1997

"Allegheny Oil Powers: Documenting Endangered Cultural Resources in Allegheny National Forest", Christopher Marston, 2000

"Technology on the Frontier – Mining in Old Ontario", Dianne Newell, 1986

"Petroleum Mining and Oil-Field Development — a Guide to the Exploration of Petroleum Lands, and a Study of the Engineering Problems connected with the Winning of Petroleum.", A. Beeby Thompson, 1910.