Most people are familiar with friction loss and velocity requirements when it comes to pump discharge lines and the impact these factors have on overall system performance. In the world of hydraulic power packs, hydraulic tools and hydraulically driven submersible pumps, the same factors must be considered to insure that enough energy is being efficiently transferred through the power unit and on down to the hydraulic motor powering the tool or submersible pump.
Each size of hydraulic hose has limitations when it comes to how much flow can be pushed through the Inside Diameter (ID) without adversely affecting both working pressure on the input side and back pressure on the return side of the system. So, choosing the right diameter hose is critical for eliminating inefficiencies which result in heat generation and excess back pressure in the motor.
The general rule for velocity in a pressure line is 10-20 feet per second and on the return side it should be between five and ten feet per second. The use of different ID hoses will alter this velocity, and the right size hose will insure that your system runs efficiently. This can be the case whether you are running 50 feet or 500 feet of hydraulic line out to the tool or submersed pump. The link below provides an industry standard reference to hose selection as it relates to velocity.
As mentioned above, the size and length of the hose run could also create an adverse impact on both the high pressure fluid delivery and the system back pressure. In fact, the hose size can have a greater effect on the tool performance even if the velocity of the fluid is within range.
For example, if a power unit is outputting 8gpm at 2500psi and you are using ½” (-8) hydraulic hose for delivery, the pressure loss across a 50 foot run is 33psi and the velocity of the fluid is 13f/s (ideal). If you add hose to a length of 150 feet the psi loss jumps to 99psi while the velocity remains the same. And, if the one way hose length increases to 300 feet, the pressure loss jumps to 300psi with the same 13f/s velocity. So at 300 feet out, the system pressure drops by over ten percent and the added friction also builds harmful heat which will eventually damage the critical hydraulic components as the oil quality degrades. And of course the performance of the tool or pump will drop off by at least the same percentage.
Not using the right size hose on the return side does not result in a pressure loss, rather it creates a pressure build. This increase in back pressure, when not controlled, can lead to failure of the lip seal in the hydraulic motor which can lead to mechanical seal failure and possibly a loss of system hydraulic oil in to the material being pumped. Before providing some sample numbers, consider that any lip seal in a hydraulic motor is typically rated for 100psi. With that in mind, using the same inputs as above (8gpm at 2500psi), and the same starting length of 50 feet of ½”ID hose, the system back pressure would be 33 psi at 13 f/s (the system pressure of 2500psi has already been expended doing the work). Moving to 150 feet of return hose jumps the back pressure to 99psi or the limit of most lip seals, and a 300 foot hose run results in back pressure of nearly 200psi.
In both cases above, up-sizing the hydraulic hose one size to 5/8” (-10) has a dramatically positive effect on system pressures. On the input side, the pressure loss of 300psi drops down to 67psi and on the return side, the back pressure drops to the same 67psi. These new pressures realized are dramatically better and will help insure that your system runs more efficiently.
The other thing to consider as you set up the hydraulic lines is the number of quick disconnects or other connections across the length of the run. It is always better to have fewer connections as each junction creates friction which impacts both delivery and back pressure.
Taking the time to think about the hoses and making sure to choose the right hose will go a long way towards insuring that your hydraulic system runs efficient and trouble free.
Now that we got your attention, let’s explain what we are talking about. Hydra-Tech’s submersible pumps include several wear parts in the body of the pump that can be replaced should they get worn out. The internal wear parts in the 3 and 4 inch sludge and slurry pumps, and 4 and 6 inch vortex flow trash pumps have a few common parts, the wear ring, wear plate and vortex impeller that are interchangeable. To lengthen the life span of these wear parts, they are now available with a carbide coating Shieldzall, which Hydra-Tech gets from a company called Oliver Carbide Products*. This coating provides a cost effective solution to the everyday wear and tear along with the harsh abrasive environments that our submersible pumps are used for. Some of these challenging applications include pumping driller’s mud, mine slag, dredge work, stones and rocks of all sizes and of course abrasive sand. A common statement Hydra-Tech hears from the end user is if you can get these harsh types of material into the inlet of the pump and then get that pumpage through the volute then the pump is a success.
Hydra-Tech did a case study with one of their customers. The customer was using a 6 inch trash pump in a mine and after 8 hours the impeller and wear ring were worn down. Hydra-Tech then supplied them with the Shieldzall carbide coated wear ring, wear plate and impeller, and had them run the pump to see when the parts would get worn out. With these coated parts they were able to get 280-hours out of one set, after that amount of time the wear ring was the only part that needed to be replaced.
*Oliver Corporation is the world premier manufacturer of tools and specialty coatings utilizing nickel-brazed carbide coatings.
Just over a year ago Jeff Whittaker started working for Hydra-Tech Pumps. He knew most of the employees fairly well since most had been working for Hydra-Tech since the company moved to Nesquehoning PA in 2007. Jeff’s family acquired the business in 2005 when it was located in Mt Holly NJ.
From Jeff’s perspective, his first year:
As I sat at a desk that I made my home in my first week at Hydra-Tech, part of what I did was eavesdrop. Seriously. What better way to begin to figure out the culture and hear the Hydra-Tech end of technical calls, application calls, sales calls etc. I heard people stressing our great customer service, and I began to see it myself. In my first back order meeting where we review the orders in house, the production plan and the shipping schedule, I realized that it was a symphony of friendly ribbing, but that everyone was pushing each other to get the orders out as quickly as possible and do whatever was possible to do better than the customer expected.
On a daily basis I saw firsthand how hard Hydra-Tech’s employees work for the customer and how dedicated everyone is about their role in the whole process. It was also immediately obvious to me that Ken Reim, who founded the company back in 1977, is as passionate about the design of pumps and power units as he ever was. There is nothing he likes more than a new application and challenge.
So with a year under my belt (and a still a lot to learn) I realize that our customer service is one of our most important aspects, something that has been confirmed time after time with customers I have spoken to. So as much as we are selling hydraulically driven submersible pumps and hydraulic power units, we are also providing solutions to pumping needs and working hard for your business every day.
Manufacturer of the Year – Hydra-Tech Pumps, proudly recognizes the efforts of all of its employees for the contributions made which have enabled us to be recognized as the Manufacturer of the Year by Gorman-Rupp Pumps. The award comes to us as a long time GR vendor and participant in the Supplier Scorecard evaluation program that Gorman Rupp has been using since 2006.
Pre-dating the Supplier Scorecard, Hydra-Tech’s relationship with GR goes back to the mid 90’s. During that time period Gorman-Rupp recognized that Hydra-Tech’s USA made products offered both the best value and the best technology in the world of submersible pumps driven by hydraulic power. With that in mind, they invited Ken and his partner to Mansfield, Ohio to help create the right product offerings for our joint customers. After some brief negotiation, a handshake deal was done, and Gorman’s hydraulically driven submersible pump and hydraulic power unit program was born. While G-R’s line of hydraulics are limited to three, four and six inch pumps along with the compatible power units, Hydra-Tech’s product line has grown to include pumps from two inch discharge up to 24” axial flow pumps.
The GR hydraulic product line is manufactured in Pennsylvania by Hydra-Tech and in accordance with G-R’s quality standards. The equipment is private labeled and carries to market the distinct Gorman Rupp color scheme.
In addition to the standard products, GR and HT have partnered on some custom projects, including sound attenuated auto-start systems employed in western Canada, small auto-start diesel packages in use in Mexico City and a pneumatically activated auto start system for use in a permanent industrial setting.
We thank Gorman Rupp for the honor and want all of our client companies to understand that we work each and every day to be the Manufacture of the Year for each and every one of our valued customers.
Comparing Electric Submersible Pump with Generator and Hydraulic Submersible Pump Systems.
Electric Submersible with Generator:
- Submersible pump is not affected by suction lift limitations
- Generator must run at constant full speed at all times
- Fuel usage is high regardless of demand on pump
- May be unsafe to operate in certain areas
- Potential shock hazard
- Costly to repair
Hydraulic Submersible: (from Hydra-Tech Pumps)
- Submersible pump is NOT affected by suction lift limitations
- Variable pump speed to suit job conditions
- High overall efficiency and low fuel consumption
- Can be used in hazardous environments
- Many different pumps can be driven from a single power unit
- Pump and power unit are field serviceable
- Easy and inexpensive to maintain
Here we are ready to go to work laying a foundation at the bottom of the 40 ft. deep excavation. We are keeping ahead of the incoming groundwater with our electric submersible pump connected to the local electric supply when suddenly the power goes out! No problem. We run over to our backup diesel self-priming pump and start it up. What? Why isn’t it pumping?!!
Oh, that’s right. The dig was deeper than we anticipated and this type of pump can’t lift the water that high. Now our only choice is to stop everything and try to lower the pump into the hole until it can catch prime and hope it can keep up until we find a better way. Tic-Toc, Tic-Toc…as time and money passes by.
Wish we had used a hydraulic submersible to begin with.
My Submersible Hydraulic pump has a blown motor lip seal, what’s the cause of this?
Seal failure on the hydraulic motor is usually caused by excess pressure build-up in the motor casing.
Some other common causes:
- Not connecting the quick disconnect fitting completely on the wing style fittings.
- Hooking up the pressure line before the return line causing the pressure in the hose to build up with no place to go except past the motor lip seal and mechanical seal and into the pumpage.
- Disconnecting the return line before the pressure line causing the same as above, no outlet for the pressure. **The motor lip seal is not designed to hold the full system pressure only internal leak oil for lubrication.**
- The return hose might be too long and/or diameter might be too small.
- Clogged return hose or coupling obstructing the return of oil flow back to the tank.
- Power unit, Bobcat, Truck, or Excavator hydraulic controls may not be an OPEN CENTER or motor control spool meaning the return is closed off and traps the pressure at the motor.
- The power unit is putting out too much pressure and hydraulic flow for the motor.
- Running the motor at full speed in cold weather without allowing the hydraulic oil to warm up first.
*Always be aware of your max hydraulic motor pressure and flow requirements.
*Before you hook up your power unit know what your power unit’s output is to prevent bodily damage and equipment failure.
Vortex Impeller Pumps Solve Solids Handling Challenges.
Think about how effective the average toilet is…It creates a vortex action using water flow and pressure to quickly and efficiently dispose of human waste, sanitary products and the occasional dead goldfish. The vortex energy found in the common toilet is the same kind of energy which makes our vortex impeller pumps perfect for handling stringy materials, rags, slurry and many types of solids and semi-solids.
Consider also, that engine driven hydraulics powering a motor atop our submersible pumps magnify this vortex effect, creating an even more effective pumping system. Using any vortex type impeller submersible pump will help eliminate the clogging which sometimes occurs in channel impeller pumps. In addition our vortex pumps do well when pumping sludge, sewage, silt and even the occasional goldfish.
A popular question we are asked is “Why do you need to use an open center hydraulic circuit when driving a submersible pump?” The quick answer is to keep the pump from coming to an abrupt sudden stop.
Let’s think of it in terms of driving a car. You are driving your car and the traffic light turns yellow and then red. You apply the brakes just enough to slow the car to a stop. Imagine what it would be like if you had to slam on the brakes or jam the transmission into ‘Park’ every time you needed to stop. Both you and the car would experience excessive wear and tear. A closed center hydraulic system acts the same way when driving anything with a hydraulic motor, especially driving a pump.
1.) In a closed center circuit, the valve controlling the direction of oil on the submersible is placed in the center (off) position, the oil returning from the submersible pump is blocked and has nowhere to go. The pump impeller goes from spinning fast to an abrupt halt. This can cause damage to the pump and cause motor seal failure.
2.) In an open center circuit, the valve controlling the direction of oil on the submersible pump is allowed to pass through the valve and return to the oil reservoir and allows the pump impeller to slowly wind down. See this link for a hydraulic diagram that shows a typical open center hydraulic circuit.
All of Hydra-Tech’s standard power units are single direction open center systems that provide safe hydraulic power matched to the pumps they drive. If it is impractical to change the existing hydraulic circuit on the power unit or vehicle you are using to drive a submersible pump, there is another solution. The Hydra-Tech Pump can be used between the power source and the submersible pump to prevent sudden stops, wrong rotation or over-speeding and allow you to control the pump output.
Two factors must be used to determine the maximum length of hydraulic hose you can run from the hydraulic power unit to the submersible pump.
On the pressure side friction losses in the hose and couplings will reduce the amount of pressure available to the hydraulic motor. This will cause a reduction in power from the motor and may have an effect on the submersible pump output.
On the return side friction losses not only will effect performance but also create excess backpressure that can damage the hydraulic motor and possibly cause seal failure in the motor.
As a rule of thumb we recommend going to a larger return hose on running distances greater than 150ft (45m). Use a larger hose on the pressure side on distance over 150 ft (45m).
Case drain lines (third lines) are used to relieve any excess pressure build-up in the hydraulic motor casing on the submersible pump. The larger the hydraulic flow capacity of the system, the greater the need for case drain lines. All of Hydra-Tech’s power units 25HP (15GPM) and above have provisions for case drain lines to be fitted. All of Hydra-Tech’s pumps that operate with input flows over 35 GPM (132LPM) have case drain lines fitted as standard. Pumps that operate with flows from 15 to 35 GPM only require case drain lines when you are using 150 ft. (45m) or more hydraulic hose from the power unit to the pump. Units under 15 GPM (57LPM) normally do not require case drain lines and in applications over 150 ft from the power unit to the pump, a larger size return line can be used to reduce back pressure.
Gas & Oil Expo, 2013 – Spent a couple days touring the Expo in Calgary Alberta. The show featured a lot of environmental services companies, several consulting and engineering firms, a good representation of construction and pre-fabbed structure companies and a large collection of safety equipment manufacturers and suppliers.
On the pump side, there were several companies , but not much in the way of electric or hydraulic drive submersibles. Positive displacement pumps were well represented as were chemical injection pumps and a few centriugal pump companies. Expect to see a larger contingent of pump companies at the Oil Sands Conference this fall in Fort McMurray.
The Carbon Footprint created by all pumping systems are a not so hidden cost associated with any pumping job. When comparing electric drive submersible pump systems to hydraulic drive packages, you might be surprised to learn that the overall efficiency of hydrualic drive systems means less fuel comsumption and less CO2 emissions than like-sized generator or electric grid based pumps. You can make some comparisons of your own using our independently commissioned Carbon Footprint calculator found on the landing page of our website.
Vicosity and its affect on pump performance is often difficult to estimate. Since most pump curves are based on water, understanding true system outputs when pumping thicker materials tend to be based on practical experience rather than hard data.
To get more accurate data, we at Hydra-Tech plan on investing significant resources to put four or more of our pumps through a weeklong series of test at a nationally recognized test facility. Following those tests, we will compare our actual results to the performance figures predicted by several of the online viscosity correction calculators….Stay tuned for more details!
Elastomers and Bio-Degradable Hydraulic Oil- The environmental benefits of using zinc-free and/or other types of bio-oil are significant. There are some “no-sheen” products out there which are especially attractive for use when working in sensitive areas.
Just a word of caution when selecting which oil might be best for your situation…Check the chemical compatibility of the elastomers in your O-rings and seal components; some of these bio-oils can aggressively attack certain types of seal and O-ring materials.
Nothing is more aggravating than having an equipment breakdown on a job site. Even more irritating is finding out the unit can’t be repaired on-site and has to be taken back to the shop for repairs.
Electric submersible pumps and electric generators are notorious for this and in most cases cannot be repaired on-site.
With that in mind, Hydra-Tech has engineered simplicity into pump designs that allow for field serviceable repairs.
Some examples are:
- Hydraulic motors that can be changed out in minutes.
- Pump bodies that separate quickly with a few simple hand tools.
- Hydraulic hoses that are interchangeable and can be switched out easily.
- Easy access to service points, filters and components on power units.
- Customer tech support services that will help diagnose any issues that may arise and quickly determine the best way to solve them. Many times a simple fix is all that’s needed and your staff can have the unit back on-line without needing specially trained technicians.
Efficiency and Effectiveness – How watching the Pressure Gauge, Tightening connections and keeping things “cool “will prolong the life of any hydraulic system.
Our engine or motor based hydraulic power units convert fossil fuels or electricity in to hydraulic flow and pressure which does the useful work of powering the rotation of the impeller in our submersible pumps or any other device fitted with a hydraulic motor.
As with any energy creator, system components which don’t help with doing work, hurt by creating heat. So, to insure the most efficient use of the primary fuel, careful attention must be paid to all of the components of the hydraulic system and how each hydraulic pump, motor, valve, fitting and piece of plumbing create inefficiencies by generating heat.
Once the design is done and the user puts the whole system to work, the two best ways to keep things cool are: making sure the hydraulic connections at the hoses and submersible pump are fully seated and only running the engine speed up to the point where the hydraulic system pressure shown on the pressure gauge is no longer climbing. When the pressure on the gauge stops increasing, this means that the system is doing all of the work it can do given the pumping conditions. Increasing engine rpm beyond this point does more harm than good. Specifically, running engine speed up beyond the pressure “sweet spot” does nothing for system effectiveness (no more work gets done) and wastes expensive fuel. In addition, efficiency is hurt because the excess hydraulic flow resulting from the engine mounted hydraulic pump turning faster dumps over the small orifices in the relief valve which in turn creates nothing but HEAT. This heat breaks down the hydraulic oil, creates blow by and generally does bad things to all the critical system pieces.
In the end taking two simple steps, keeping your eye on the pressure gauge and making sure things are tight will always result in a more efficient and effective pumping system.
Tested, approved and deployed by a purchasing arm of the military, Hydra-Tech’s HT50DQV powers submersible pumps for salvage operations and hydraulic power for dive projects. Like all Hydra-Tech sound attenuated packages, these units are perfect for residential areas and other noise sensitive locations.
Centrifugal and Submersible Pumps have one thing in common, there is no one size or type that fits all applications. Different impeller and pump body styles are required to do different jobs. Here are some of the different impeller types and what they are used for:
2) Vortex Impeller – Used for pumping stringy solids and debris-laden liquids
3) Centrifugal Screw Impeller – Used for pumping oils and other viscous liquids
4) Propeller – Used for pumping high volumes of water at low heads
5) Shredder Impeller – Used for chopping solids to smaller pieces when they enter the pump
6) Closed Channel Impeller – Used for pumping sewage and wastewater
7) Mixed Flow Impeller – Used for high volume water pumping at low to medium heads
8) Semi-Open Impeller – Used for trash and debris laden liquids
9) Hardened Sand/Slurry Impeller – Used for pumping abrasive liquids
A common question asked by Hydra-Tech customers is:
Why is there a small stream of water flowing from the top cover of my pump?
There is a logical answer to this, and it is not that the pump is broken. Hydra-Tech Pumps manufactures one (1) of the four (4) bolts used to hold the water plate in place. This bolt has a 1/8″ hole through the center of it. The purpose is to allow trapped air to escape from the volute (pump body) when placing the pump into the liquid for the first time.
Maintenance: If this hole gets clogged, you simply just push a pick through the hole to clean out the dried up debris.
Pumps are mechanical devices used to move a liquid from one place to another. On the most basic level, without allowing for friction losses, the difference in altitude from place A to place B is called the pump head requirement. It is measured in linear units such as feet or meters. The flow of the pump is measured in volumes per unit time, such liters per minute or US gallons per minute. The pump curve shows the relationship between these two measurements.
Here is an example of a curve and how to interpret it.
We calculate feet of head to see how much pressure (psi=feet of head /2.31) the pump must overcome to deliver the resulting output flow at the delivery point.
Capacity– volume of liquid, is on the x-axis or horizontal axis
**Make sure you take notice to the unit of measure each one is being measured in. **
This point is showing this particular pump can supply 210 GPM @ 45 feet of head
You will notice each line is labeled from A-D, this is showing the different hydraulic inputs needed to make the pump run at the different levels of efficiency.
For example, in order to get your pump to pump 75 GPM @ 50 feet of head you would need a hydraulic unit able to provide 6 GPM @ 1500-2100 PSI, which you can find at Hydra-Tech Pumps with their HT13G portable hydraulic power unit.
*The maximum shutoff head (where all flow stops) of this pump is 75 feet. The best efficiency point of the pump would be about 85% of the maximum shutoff head. So at 64 feet the pump would be running most efficiently.
Often overlooked when evaluating or calculating pump performance is the role of discharge hose. If you are using hose rather than pipe, the type of hose selected can and does have a major impact on pump output and is a common reason for pump system under-performance. When choosing a type of discharge hose, you should consider more than just the price point.
So when asking what’s best for my application, consider that the most common options in hose (listed from lowest cost to highest) are lay flat, rubber, reinforced rubber and wire reinforced vinyl. These options, as with many things, hold true to the old saying, “you get what you pay for.”
Specifically, the lower cost lay flat and non-reinforced rubber hose create additional head pressure as the pumps must work against the actual head and also work to keep the discharge hose expanded while both starting and pumping. While not good for all jobs, this type of hose can be effective for lower head, short horizontal run-out applications, where there is not a lot of total head to overcome. The other thing to consider when thinking about lay flat hose is the question of durability. It is easily the most sensitive when it comes to abrasion and puncture, and in severe conditions, lay flat can quickly turn in to a sprinkler hose. Non-reinforced rubber is much more durable than lay flat. However, with any non-reinforced hose, kinking and the resulting discharge line obstruction can often occur.
As I am sure you figured out by now, either type of reinforced hose will eliminate the false head created by the collapsing hoses and as a result the impact on system performance will be minimized.. So when choosing between the reinforced rubber and wire reinforced vinyl, you should think about things like flexibility and weight. The vinyl product is almost always lighter with a better bend radius, but can also be a bit pricier than the reinforced rubber. The rubber on the other hand typically is more abrasion and puncture resistant.
To sum up, the same discharge hose is not right for every job. Consider all of the job conditions and choose the hose which create the best mix of optimal system performance, durability and cost minimization.
In this world where we all strive to save energy and develop products that will do just that we also have to be aware of the trade offs that can come with it. In the pump world it means making pumps that can achieve the highest efficiency and use less power to drive them. An example would be a water pump running 24 hours a day in a cooling system at a plant. The difference in the cost of electric power consumed by a pump that is 50% efficient versus one that is 75% efficient could be huge and over time the more efficient pump pays for itself in the energy saved. This would be great if we only pumped clear water all the time.
In the real world we are confronted with many pumping challenges. The liquids may contain solids, which can be heavy or viscous, stringy, abrasive and may even need to be chopped or agitated in order to flow properly. What good is a high efficiency water pump when it becomes clogged with solids and stops pumping?
This is why there are so many different types of pumps designed for specific tasks. While pump manufacturers always want to build pumps that are efficient, making sure the pump does the job is the first priority. When that tank full of waste material has to be moved or that lake needs to be dredged or that sewer needs to be by-passed while repairs take place, using pumps that are practical for the job become more important than the efficiency of the pump.