SINGLE ACTING RECIPROCATING PUMP
If a reciprocating pump uses one side of the piston for pumping liquid, then it is known as a Single Acting Reciprocating Pump. A reciprocating pump is often a positive displacement pump that works on a movement of piston reversal concept within a cylinder, which draws fluid during forward stroke and delivers it under pressure during return or reverse stroke.
The pump usually works at low speeds and is linked to a electric motor via V-Belts. The reciprocating pump is very effective at low flow rates and high heads of liquids. One such type of pump is particularly prevalent in oil drilling operations.
Volumetric Pumps or Positive Displacement Pumps
Volumetric pumps generate suction and push by varying the volume within a chamber. The fluid is drawn into the chamber, which creates a vacuum, and then released, raising the pressure within. A mammal’s heart, for example, is a volumetric pump.
Because the chamber has a maximum specified and stable capacity, volumetric pumps transport consistent quantities of liquid during each working cycle. A complete revolution (360°) of the driving shaft constitutes one working cycle. The volume pumped per unit of time (l/min) is proportional to the pump speed and is independent of fluid pressure.
Reciprocating Pump Classification
Based on whether water is in contact with one or both sides of the piston, reciprocating pump is classified as:
(i) single acting cylinder
(ii) double acting cylinder
The pump is called as a single acting reciprocating pump, if the water, only comes into contact with one side of the piston, and in a double acting reciprocating pump, if the water comes into contact with both sides of the piston.
Description of Single Acting Reciprocating Pump
The main parts of a single acting reciprocating pump are discussed below.
1.Cylinder, Piston, Piston Rod, Connecting Rod and Crank
A single action reciprocating pump consists of a piston, which moves forwards and backwards inside a close fitting cylinder. The movement of the piston is obtained by connecting the piston rod to the crank by means of a connecting rod. The crank is rotated by an electric motor.
2.Suction Pipe and Suction Valve
Suction pipe is connected to the cylinder. Suction valve is a one way valve, i.e., non-return valve. It allows the liquid to flow in one direction only. That is, it permits the liquid from the suction pipe to the cylinder.
3.Delivery Pipe and Delivery Valve
Delivery pipe is connected to the cylinder. Delivery valve is also one non-return valve. It permits the liquid to flow in one direction only. That is, it allows the liquid from the cylinder to the delivery pipe.
Working Principle of Single Acting Reciprocating Pump
In a single-action reciprocating pump, liquid acts on one side of the piston only. A single-acting reciprocating pump which has one suction pipe and one delivery pipe; It is usually placed above the liquid level in the sump.
When the crank rotates from IDC to ODC the piston moves towards right in the cylinder. This is called suction stroke.
Now, the volume covered by the piston within the cylinder increases. On the free surface of water in the sump, atmospheric pressure acts. Thus there is a pressure different at the two ends of the suction pipe which connects the sump and the cylinder. This pressure difference between the free surface and inside of the cylinder causes the flow of water from the sump into the cylinder through the suction valve, which is kept open.
During this stroke, the non-return valve at the delivery side will be closed by the atmospheric pressure existing in the delivery pipe. At the end of this stroke, the cylinder will be full of water, the piston reaches the right end, which is called outer dead centre since, the water is continuously sucked into the cylinder, this stroke is called suction stroke. At the end of this stroke, since the pressure in the cylinder is atmospheric, the suction valve is closed.
2.Return stroke or Delivery Stroke
When the crank rotates the piston from its extreme right position starts moving towards left in the cylinder. This is known as Return or Delivery Stroke.
The movement of piston towards left increases the pressure of the liquid inside the cylinder to a pressure more than atmospheric pressure. Therefore, the Suction valve closes the delivery valve opens. The liquid inside the cylinder is forced into the delivery pipe through the delivery valve. Consequently, the liquid is raised to the required height. The liquid is discharged at every alternate stroke.
Metering Pump / Dosing Pump Technologies
There are three types of metering and dosing pumps: piston, plunger, mechanical diaphragm, or hydraulic diaphragm. The core technology has been proved, and ongoing improvements, such as the introduction of new production methods and materials, ensure that these pumps can meet the expanding and diverse needs of all industries.
Because many of today’s pumps are so flexible that they are suited for a wide variety of applications, finding the best appropriate pump technology for a given application or process system can be hard for the non-expert in pump technology. When a particular amount of liquid must be introduced into a process system, rotary positive displacement pumps, capillary pumps, and reciprocating positive displacement pumps all bridge application boundaries.
Reciprocating Piston Pumps vs Reciprocating Plunger Pumps vs Reciprocating Diaphragm Pumps
The primary (suction) stroke of the piston in a piston pump generates a vacuum, opens an intake valve, closes the exit valve, and pulls fluid into the piston chamber. As the piston reverses its motion (compression stroke), the intake valve closes under pressure and the outlet valve opens, enabling the fluid in the piston chamber to be released. A basic example is a bicycle pump. Double-acting piston pumps have intake and output valves on both sides of the piston. On one side, the piston is in suction, while on the other, it is in compression. In industrial applications, radial variants are more complicated.
Plunger pumps work in the same way. The amount of fluid carried by a piston pump is determined by the cylinder volume; the plunger size determines the volume of fluid pushed by a plunger pump. To keep the pumping motion going and minimise leaks, the seal surrounding the piston or plunger is critical. A plunger pump seal usually easier to manage in general since it is stationary at the top of the pump cylinder, whilst the seal around a piston moves up and down inside the pump chamber on a regular basis.
A flexible membrane, rather than a piston or plunger, is used to move fluid in a diaphragm pump. The capacity of the pumping chamber is raised by extending the diaphragm, and fluid is pulled into the pump. The volume of the diaphragm is reduced as it is compressed, and some fluid is expended. Diaphragm pumps are suitable for pumping hazardous fluids since they are hermetically sealed devices.
What Are Reciprocating Plunger Pumps and How Do They Work?
A motor and the pump make up a conventional reciprocating pump arrangement. The motor’s shaft is linked to the reciprocating pump’s crankshaft through a driveshaft and v-belt.
When the motor is turned on, the shaft spins, causing the reciprocating pump’s crankshaft to revolve proportionally, delivering energy from the motor to the pump. Several plungers, generally two or more, are located inside the pump and are linked to the crankshaft by extension rods. During each entire rotation of the crankshaft, each plunger enters and exits a hermetically sealed fluid chamber once.
By alternating vacuum and pressure inside the fluid chamber, the plungers modify the volume of the fluid. Positive displacement is the term used for this phenomena.
The resultant vacuum allows fluid to enter the chamber from the intake through the suction valve as the plunger departs the fluid chamber. The plunger produces pressure in the fluid chamber, causing the fluid to be ejected through the discharge valve. The majority of reciprocating pumps have several fluid chambers that work independently of one another. When one chamber drives out fluid, another chamber is filled.
This permits fluid to flow through the pump at a steady and continuous rate. Reciprocating pumps are thus also known as constant volume pumps.
Reciprocating Pumps have several Advantages Over Centrifugal Pumps
For many applications, you may be forced to choose between a reciprocating pump and a multi-stage centrifugal pump. Both pump designs have advantages and disadvantages, depending on:
- Where will the pump be installed?
- The fluid that is being pumped
- Plans for further growth
- System parameters that can be customised
- Issues with operation and maintenance
- Personnel familiarity with the pumps and previous experience with them
Compared to centrifugal pumps, reciprocating pumps have the following advantages:
- A centrifugal pump’s flow rate typically fluctuate during performance, whereas a reciprocating pump’s flow rate remains constant.
- High-pressure, low-flow operations are excellent for reciprocating pumps. Reciprocating pumps create higher pressure per operation than centrifugal pumps, which may be more successful in high-volume-discharge circumstances. Reciprocating pumps where used in water jet cutting applications, for example, it may create pressures up to 10,000 PSI.
- Priming is usually required for centrifugal pumps, whereas priming is seldom required for reciprocating pumps.
- Reciprocating pumps have better efficiency than most other types of pumps, typically reaching 90 percent or more.
The energy consumption of a pump is directly proportional to its efficiency. The energy expenses of a centrifugal pump are generally 1.40 to 1.90 times higher than those of a reciprocating pump. If the centrifugal pump works at less than 30% efficiency owing to the system’s performance not matching the pump’s performance, this might be as high as 2 to 3 times.
Maintenance issues of reciprocating and centrifugal pumps are:
Centrifugal pumps fluid end parts and shaft packing or mechanical seals are common maintenance components. Some of these things may be repaired on the spot, but most industries will send them to a certified repair shop for maintenance or overhaul. Many designs may not tolerate fluids loaded with solid particles, which might increase wear, due to tight tolerances and rapid rotating components.
Pump with reciprocating action in a reciprocating pump, usual maintenance parts include plunger packing, plunger, and suction/discharge valves. They may be repaired on the field. A skilled technician can easily do the task. Pump speed, materials utilised, and the amount of fluid delivered all influence the frequency of maintenance issues.
Reciprocating Pumps Industrial Applications
In various applications, a broad variety of industries utilise reciprocating pumps. Repeatable and accurate mechanical actions occur in the use of reciprocating pumps. Common reciprocal pumping industries include:
Reciprocating Plunger Pumps in the Oil and Gas Sector
Because oil and gas industries influences a variety of critical industrial sectors, it is a key contributor to the global economy. In the oil and gas sector, reciprocating plunger pumps and their performance are critical. These pumps help the nation’s petroleum sector collect oil and other natural resources from subterranean formations.
Pumps and parts of pumps such as valves and plungers are ideally suited for this purpose. Because the valves and plungers used in these pumps are crucial to the performance of these operations, they must be robust and durable.
Oil and gas applications include salt water disposal, primary, secondary, and tertiary injection wells in petroleum productions, and petroleum transfer activities in the field, at refinery plants, and at chemical production plants where petroleum products are utilised as a component.
Reciprocating Plunger Pump in Chemical Industries and Pharmaceutical Industries
Many manufacturing facilities and chemical manufacturing facilities employ valuable chemical compounds such as acids, caustics, solvents, and polymers in the production process. Metallic and non-metallic corrosion resistant materials for the safest fluid handling in chemical processing and for transferring the most toxic chemicals in the industry.
Many manufacturing processes employ highly corrosive chemicals, either as a feed stock for the production of end products or to alter the pH of mixtures to allow important chemical or biological interactions. Sulphuric acid is the most widely utilised corrosive in business. Sulphuric acid, which can be used to make fertilisers, might potentially cause skin and deep tissue damage.
Handling these extremely corrosive compounds necessitates careful pump selection to guarantee fluid containment and emissions control. Pump seals are the part of the pump that is most sensitive to corrosive substances. Pumps must be strong enough to handle these toxic chemicals and prevent leakage, according to process engineers.
Pumps have a hard time dealing with abrasive mixes. Solid particles in these combinations can degrade internal pump components, reducing pump performance significantly. Certain chemical pumps are also used for flow measuring and control pumps with accurate chemical volumes.
Reciprocating Piston Pump in Sewage / Waste Water Treatment Applications
Waste water treatment now is more essential than ever with radical global climate changes and severe droughts. In commercial and residential buildings, as well as industrial zones, wastewater treatment is a must.
Wastewater / sewage treatment plant with mechanical, biological and chemical treatment of waste water, sludge treatment, overflow structures and flooding, tank cleaning, drainage of surfaces, and wastewater treatment drainage are a few of the applications. Wastewater treatment pumps are intended particularly for the pressurised pumping of sewage and wastewater containing destructible particles, and some can be placed dry or submerged.
Wastewater treatment plants are required in sectors such as chemical, food processing, manufacturing, pharmaceutical, and many others to comply with government laws and standards. There are three main types of treatment processes: primary, secondary, and tertiary. The type of treatment technique employed determines the quality of treated water.
Depending on the volume of wastewater, pollutants in it, the level of purity required, and other variables, various organisations use different types of treatment procedures. What all wastewater and sewage treatment facilities have in common is that they all use reciprocating piston wastewater pumps to complete the operation.