A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

 

Performance curve
Graph which indicates the pump’s performance showing the curve consisting of the flow rate and discharge head values. Flow rate and discharge head are indicated with reference to a specific type of rotor, diameter and to a particular pump model.

 

Positive suction head installation
the pump is placed at a lower level than that from which the liquid is drawn so that it enters the pump without any difficulty.

 

Priming
Filling of the pump or the pipes by emptying the air contained therein.

 

Pressure loss
The pressure loss in a hydraulic circuit is the difference in pressure between the circuit’s inlet and outlet side, corrected by the difference in elevation, due to the liquid’s motion inside the circuit. Generally it is expressed in water column meters for liquids and mbar for gases.
It is caused by the friction of the liquid along the pipe walls, proportional to the length of the pipes themselves, proportional to the flow speed square and other variables which depend on the nature of the liquid being pumped.

 

Peristaltic pump
The peristaltic pump works by “flow pressure” which acts on the flexible pipe; such flow pressure is exercised by rollers which turn parallel to the axis, and which are supported by a roller holder.
The slow rotary motion of the roller-holder is transmitted by a two or three steps motor reducer.

 

Polyethylene UMWHPE
Polyethylene with a high molecular weight (> 1.000.000) with an excellent shock resistance.
Compared to the various PE resins with a lower molecular weight, this type is less rigid and more shock resistant and is therefore more appropriate for applications where shocks are repeated.
ADVANTAGES
Good shock resistance even at low temperatures
High resistance to chemicals typical of polyolefin resins.
High resistance to abrasion
Low friction coefficient
DISADVANTAGES
Compared to technopolymers, it has a low mechanical resistance: traction, bending, compression, etc. as well as a low thermal resistance. It is less rigid than PE resins with a lower molecular weight.
APPLICATIONS
Mechanical: its low friction coefficient, its high resistance to wear and its lack of hygroscopicity make it ideal for bearings or other mechanical parts with not very high loads even if they work in water.
With food: it is physiologically inert and is approved by the various authorities for use in contact with food.
Because of this characteristic, this material is widely used in machines for the food industry, for liquid food pumps, etc.
Electrical: because of its excellent dielectric characteristics and stability to weather it is being used more and more by this industrial segment.
Chemical: high resistance to solvents, greases, oils, paraffins, acids and alkali. It is used for components for the chemical industry.
Use temperature: from -50°C to 120°C

 

Polymer
A macromolecule, meaning a molecule with a high molecular weight, formed by the union of a large number of small molecules (monomers) either identical or different (copolymers) joined in a chain through the repetition of the same type of bond.

 

Polypropylene (PP)
Polymer made by the polymerization of propylene, which derives from fossil fuel (petroleum, gas and coal).
PP has a higher mechanical resistance than PE. It is resistant to alkali and acids and is therefore used by the chemical industry for parts subject to a relatively moderate strain.
ADVANTAGES
High chemical resistance
Resistance to traction, rather high for a polyolefin resin.
Low specific weight
Easily machined and welded
DISADVANTEGES
Compared to technopolymers, it has a low mechanical resistance: traction, bending, compression, etc, and a low thermal resistance. Compared to PE, it is more rigid and less shock resistant.
APPLICATIONS
Mechanical: it is used for mechanical parts in corrosive environments; compared to polyethylene resins with a high molecular weight, it has a higher resistance to traction than PE H.M.W.
With food: physiologically inert when neutral in color, it is approved for contact with food.
Electrical: because of its excellent dielectric characteristics and stability to harsh weather conditions it is being used more and more by this sector.
Chemical: PP is mostly used by the chemical industry because of its high resistance to acids and alkali for its superior thermal resistance compared to PVC. It is used for components by the chemical, galvanic and petrochemical industry, and for the construction of valves, flanges, gears, etc. It is inappropriate for use with highly concentrated oxidizing acids.
Use temperature: from 4°C to 70°C

 

 

PPS - polyphenylene sulphide  (i.e.: RYTON®)
The PPS polyphenylene sulphide is a technopolymer for high temperature technological applications.
This family of resins, whose characteristic is an excellent processability, behaves very similarly to the reinforced thermosetting resins since if combined with various fillers (glass fillers, mineral fillers, pigments) it acquires exceptional mechanical, chemical and self-extinguishing characteristics. PPS has a combination of unique characteristics.
CHEMICAL ASPECTS
PPS is an aromatic crystalline thermoplastic polymer, with a symmetrical linear chain like structure made up of alternating sulfur atoms and phenylene rings in a para substitution pattern.
The polymerization process has been developed by Phillips Petroleum Company (USA) and consists in a reaction between p-dichlorobenzene and sodium sulphide in a polar solvent. The PPS obtained by polymerization comes as a white fine powder with a melting point of about 288°C.
When this polymer is heated at a sufficiently high temperature and with the presence of air, its molecular chain stretches starting a chain linking process which gives it exceptional mechanical characteristics.
RESISTANCE TO CHEMICAL AGENTS
PPS is characterized by an excellent resistance to chemical agents: particularly it is insoluble in all solvents below 200°C. PPS has an exceptional chemical resistance, as proven by the consistency of the values of its traction resistance after being exposed to a temperature of 93°C for a period of up to 3 months.
PPS can however be attacked by a few categories of chemical substances such as: oxidizing agents, strong acids, halogens, ammines and certain chlorinated hydrocarbons.
Water absorption by PPS is very low (< 0,05%), moreover, this technopolymer has a good resistance to hydrolysis in hot water.

 

PTFE
Polytetrafluoroethylene (PTFE) is a tetrafluoroethane polymer.
It is better know with its commercial names of Teflon, Fluon, Algoflon, Hostaflon,
in which stabilizing and fluxing agents are added to the polymer.
This plastic material is smooth to the touch and resistant to high temperatures (up to 200°C and more) and is used in industry to coat surfaces exposed to high temperatures and which require “anti-adherence” and a good chemical inertia.
It is a fluorinated material which is widely used for its excellent chemical resistance but poor mechanical properties.
Deformation, even under very limited weights, makes it useful for linings.
ADVANTAGES
High chemical resistance
Excellent resistance to low and high temperatures, up to 206°C
Low inflammability
Low friction coefficient
DISADVANTAGES
Its mechanical resistance to traction and compression is poor just like its resistance to deformation under weight is very poor.
APPLICATIONS
Mechanical: its low friction coefficient makes it appropriate for bearings as long as they are made to bear light loads.
With food: it is physiologically inert and is approved by various authorities for use in contact with food while for some nations its use in contact with food is doubtful. .
Electrical: because of its excellent dielectric, self-extinguishing properties as well as its stability under harsh weather conditions it is being used more and more by this industrial segment.
Chemical: extremely high chemical resistance to chemicals and alkali typical of fluorinated polymers. It is used for components of the petrochemical and chemical industry.
Use temperature: from 4°C to 260°C

 

PVDF
Polyvinylidene fluoride is a recently developed fluorinated polymer. Its main characteristic is its chemical resistance as the other fluorinated polymers. Compared to PTFE, its mechanical characteristics are definitely superior and it does not deform under weight.
ADVANTAGES
Offers the same excellent chemical resistance typical of fluorinated materials.
Compared to PTFE it has a much higher mechanical resistance to traction and compression.
Excellent resistance to low and high temperature up to 160° C. as well as to UV rays.
Very good dimensional stability.
Low inflammability.
Good wear resistance
DISADVANTES
Compared to PTFE its resistance to high temperatures is lower (160 °C ).
It has a rather high linear thermal dilation coefficient. Only partially compatible with ketones, esters, ethers, organic bases and alkaline solutions.
APPLICATIONS
Chemical: very high chemical resistance to acid and alkali typical of fluorinated polymers.
It is used for components of the petrochemical and chemical industry
With food: physiologically inert when neutral in color, it is approved for contact with food by various authorities. Because of this characteristic, this material is widely used in machines for the food industry, for liquid food pumps, etc.
Electrical: because of its excellent dielectric characteristics, its self-extinguishing properties which do not require the addition of halogens, its stability to harsh weather conditions it is being used more and more by this industrial segment.
Mechanical: its low friction coefficient makes it ideal for bearings even when they work in water.
Use temperature: from -40°C a 160°C