1. Larox Peristaltic Pumps for Transferring (LPP-T) Education, part 2
The Solution You´ve Been Looking For
The Larox Peristaltic Pumps set the industry standard for peristaltic pump technology. Designed for heavy industrial duties, the LPP pumps are ideal for abrasive, corrosive, viscous or crystallizing media.

2. The Application Supply voltage Frequency Pump speed, rpm
Discharge head,
Bar
Specific gravity, S.G.
Flow rate,
min, max, average
m3/h
Suction conditions,
Bar
Temperature, T
Variable or fixed flow
Operating Principle
The operating principle of the LPP pump is based on the peristaltic effect. As the cylindrical rotor rotates along the hose, the process medium gets pushed forward through the hose. At the same time, the hose behind the compression point reverts to its original circular shape creating a suction effect at the pump inlet port. As a result, the hose bore gets filled with the medium. No backward flow can occur as the hose is squeezed tight by the roller.
Chemical content
Particle size ,mm
Viscosity, cP

3. Defining Pump Size Hose life defines how ”good” pump is in question
Slower rotation speed means longer hose life => ”better” pump
Customer considers hose life in hours not in revolutions!
Recommended continuous flow rates for LPP-T pumps.
LPP-T m3/h m3/h
LPP-T m3/h …3.0 m3/h
LPP-T m3/h m3/h
LPP-T m3/h …9.0 m3/h
LPP-T m3/h m3/h
LPP-T m3/h …30.0 m3/h
One Compression is All You Need
A single, bearing-mounted roller presses against the hose only once per the 360 degree operating cycle,
producing the maximum flow per revolution and offering the longest lifetime possible.
The trailblazing LPP pumps produce higher flow per hose compression than any other peristaltic pump. They are designed to operate continuously at high speeds and in high pressures without the risk of overheating making them perfect for heavy duty applications.
Unique Rolling Design
Larox LPP pumps incorporate an advanced design, which eliminates friction, maximizes hose lifetime and lowers energy consumption. The roller is mounted on a crankshaft creating eccentric rotation during the 360 degree operating cycle. Compared to conventional peristaltic pumps, the LPP pumps double the flow per hose compression.

4. Defining Pump Rotation Speed
Pump rotation speed is calculated with following formula:
Speed [rpm] = (required flow [l/min]) / (flow/revolution [l/rev]) OR
Speed [rpm] = ((required flow [m3/h] x 1000)/60) / (flow/revolution [l/rev])
Pump flows per revolution
LPP-T l/rev
LPP-T l/rev
LPP-T l/rev
LPP-T l/rev
LPP-T l/rev
LPP-T l/rev
Standard Peristaltic Pump Benefits
Standard technical features for peristaltic pumps include
Only the hose is in contact with the medium
Positive displacement
No gland water or packing
Full vacuum capability
No backward flow
Peristaltic effect
Reversible rotation
Resulting in process benefits such as
Low wear and corrosion
Dry run capability
Self-priming in suction-lift duties
Exact flow per revolution
Accurate flow
Low shear of the medium
No risk of cavitation
Example: required flow 4 m3/h => Pump LPP-T40
Define speed: Speed = ((4 m3/h x1000)/60)/1.25 l/rev = 53 rpm Gear box output speed

5. Suction Lift Effect on Pump, slide 1
- Suction lift reduses pump flow/revolution capability
- Higher suction lift => smaller output flow rate (flow/rev)
- In suction lift solutions also the pump speed affects the flow/revolution capability
- Suction lift does not have effect on discharge pressure
- Atmospheric pressure (altitude) affects suction lift capabilities!
The Larox LPP Benefits
Technical Feature
360 degree operating cycle
Only one compression per revolution
Rolling hose contact
In-line pipe connection
Low lubrication need
Process Benefits
Low wear and corrosion
Extended hose lifetime
High pressure capability
No overheating even at continuous flow rates
Simple installation
Low operating costs

6. Suction Lift Effect on Pump, slide 2

7. Suction Lift Effect on Pump, slide 3
Flow reduction must be taken into consideration when defining pump speed (flow rate)
Example:
Slurry S.G. 1.5, flow rate 4 m3/h, suction lift 2.5 meters, viscosity 1 cP (water)
Water equivalent suction lift = 1.5 x 2.5 m = 3.75 m = ~4 meters
LPP-T40 pump speed at 4 m3/h is 53 rpm
Reduction in flow because of suction lift ~7%. Pump speed must multiplied by 1.07
New speed 53 rpm x 1.07 = ~57 rpm
NOTE: Viscosity has effect on suction lift, too.
Equipped to Perform
Larox LPP pumps are equipped with in-line pipe connections; a hose leak detection unit and a patented adjustment mechanism that senses hose wear when compression is readjusted. This helps to maximize hose lifetime and minimize the risk of overcompression. The adjustment mechanism is mounted directly on the compression force making readjustment easy.

8. Suction Lift Effect on Pump, slide 4
Suction Lift Assessor
All pumps can be equipped with this assessor
LPP-T suction lift assessor 50
100
150
200
250
300
350
0,2
0,4
0,6
0,8
Assisting vacuum (barg)
Flow (l/min) at 4,5 meter
suction lift
30 rpm
40 rpm
50 rpm
60 rpm
30 rpm nominal
40 rpm nominal
50 rpm nominal
60 rpm nominal

9. Discharge Head Pressure, slide 1
Discharge head pressure can be given/calculated in different ways. Parameters used in this context:
Lenght and size of discharge pipeline (m)
Viscosity of medium (0.001 Ns/m2 = 1cP)
Slurry specified gravity (S.G.)
Discharge head (m)
Pressure after pump
If ”pressure after pump” is not given, then ALL other parameters must be specified
to calculate required discharge pressure

10. Discharge Head Pressure, slide 2
Discharge head consists of two components:
Static head Static head (no flow) is calculated with following formula:
Pressure (Bar) = S.G. x discharge head (dekam)
Dynamic head Dynamic head (flow) is calculeted with following formula:
Pressure (Bar) = pressure drop/meter (Bar/m) x pipeline lenght (m)
Total discharge head (bar) = static head (bar) + Dynamic head (bar)
Pressure drop / meter will be calculated at Flowsys; parameters: roughness
of pipe surface, viscosity, flow velocity.
Value of pressure drop caused by pipe curves must also be added.
Equipped to Perform
Larox LPP pumps are equipped with reliable hose flange and in-line pipe connections. Unique design provides immediate hose leak detection. Rigid, reliable and tight connection flanges at both ends of the hose further improve LPP pump hose’s resistance to high pressures, temperature and pressure variations and other process conditions.

11. Discharge Head Pressure, slide 3
Example:
Flow rate: 4 m3/h
Pipeline: DN50, length 90 meters
Discharge head: 35 meters (= 3.5 dekameters)
Viscosity: 1000 cP 20 degrees C)
Specific Gravity: 1.5
Calculated pressure drop = Bar/m
Static head (Barg) = 1.5 x 3.5 dekameters = 5.25 Barg
Dynamic head = Bar/m x 90 m = 3.14 Barg
Total discharge head = 5.25 Bar Bar = 8.39 Barg

12. Pump Speed (Flow) Control
- Pump flow rate can be controlled with Variable Speed Drive (VSD), inverter, frequency controller.
All Nord Gear motors are suitable for VSD use.
With standard motor in control use the flow control ratio is 1:2.5. If motor is equipped with electric cooling fan (forced cooling, separate cooling fan... ) flow control ratio is 1:10.
Example:
Nominal flow rate of pump is 4 m3/h (standard motor)
With inverter, the flow rate of pump can be adjusted
between 1.6 m3/h….4 m3/h
If motor is equipped with electric cooling fan, the flow rate can be adjusted
between 0.4 m3/h...4 m3/h
Construction Materials 12

13. Drive sizing, slide 1 Drive sizing parameters:
Required output torgue (Nm)
Required running power (kW)
Gear unit safety factor (f)
Reguired output torgue is determined by discharge head pressure
Required running power is determined by discharge head pressure and pump speed
Safety factor is given in gear unit catalogue (max output torgue/ available output torgue)

14. Drive sizing, slide 2
Required output torgue is determineted from ”Torque and power vs pressure table”

15. Drive sizing, slide 3 Example: Solution: 4 m3/h (53 rpm), 5 barg
Requirements: Torgue 240 Nm, Power 1.55 kW
From catalogue: SEE NEXT SLIDE

16. Drive sizing, slide 4

17. Drive sizing, slide 5 Result: SK9016.1VZ-100L/4 BRE40 TF
SK = gear box type
VZ = output shaft and B14 flange
100L/4 = motor frame size (2.2 kW)
BRE40 = Brake 40 Nm
TF = Thermistors (temperature sensors)
Option:
SK9016.1VZ-IEC L/4 BRE40 TF = gear unit with IEC-flange for motor connection

18. Questionnaire

19. Motor with Brake – Why?
1. To hold the rotor in upper end position when hose compression is adjusted. The adjustment must be made when the rotor is in upper position where the rotor compresses only "one" hose. Two hoses in low end position would resist adjustment too must and hose compression would be too little.
2. Brake is required to secure (hold) the rotor in upper position when the hose is changed. The mass of the rotor will drive the rotor down if the brake is not stopping the motor, especially when the hose in not in the pump giving the required resistance to keep the rotor where it is stopped. This takes place especially in LPP65 (rotor mass ~130 kg). In smaller pumps (LPP25) the mass of the rotor is not a safety problem but the brake helps when opening and closing the locking cover bolts and turning the adjustment screw.
Brake also helps when the pump is stopped against pipeline pressure. Without the brake rotor will be driven backwards to low end position by the pipeline pressure. This causes backward flow and in these cases it is impossible to stop the pump for adjustment to upper position.
Disadvantages of brake:
- Higher price of motor
- Motor is not a basic motor (even though it is still standard motor with brake)
- Manual rotation of the pump is not possible as brake is released by electric supply (manual brake release for extra price)