Estudio de la diversidad de las poblaciones virales

The­fluid­side­has­to­be­protected­against­transgression­of­permissible­levels­of­pressure­by­means­of­suitable­and­

approved safety valves.

5.3.1.1 Safety and shut-off block (SAF)

This safety and shut-off block is an accessory in hydraulics to shut-off and relief hydraulic accumulators or actuators.

Pertinet and relevant safety regulations are being met.

Design:

SAF safety and shut-off block consist of a valve block, the in-built pressure relief valve, main shut-off valve and a manually operated relief valve. Furthermore there is a tank port plus the required manometer ports. An optional electromagnetically operated directional valve permits an automatic unloading of the accumulator or actuator in case of emergency or if the unit has to be set to idle.

Function:

During operation of safety and shut-off blocks the main shut-off cock is open and the relief valve is closed. Thus the

­accumulator­is­always­charged­with­oil­as­determined­or­discharges­fluid­if­the­pressure­in­the­system­decreases.­

Type: SAF

Nominal value: 10 bis 50 liter Max. operating excess pressure: up to 400 bar

Relief / unloading / discharge:­ manually­and/or­electromagnetically Pressure relief valve: Nominal value DN12

��

main shut-off valve

port for testing manometer

valve block

relief valve safety valve DB Fig. Safety and isolating block

Fig. SAF

335 Electronic unloading optional:

��

�

� �

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manometer

main shut-off valve

port for testing manometer

electromagnetic

decompression (safety) valve decompression

(safety) valve accumulator

valve block

safety valve DB

Fig. Safety and isolating control block with electric unloading

336

5.3.1.2 DSV 10

A 3-way safety valve DSV 10 serves to secure and unload hydraulic pressure accumulators and actuators. The essential difference between SAF 10 and DSV 10 is their shut-off and unloading capabilities.

Design:

DSV-3-way safety valve consists of a valve block with in-built pressure relief valve and shut-off cock. Ports for pump, manometer, tank and accumulator exist.

An optional electromagnetically operated 2-directional valve permits an automatic unloading of accumulators or actuators.

Function:

During the operation of the accumulator the ball valve connects the pump port with the accumulator. A pressure relief valve constantly checks on the status of the accumulator.

By­turning­the­ball­valve­the­pump­port­is­closed­without­leakage­and­at­the­same­time­unloaded­to­the­tank.­The­fitting­

of­an­electro-magnetically­operated­2/2­poppet­directional­valve­we­can­achieve­an­automatic­unloading­in­case­of­a­

power cut or if the machine has to be set to idle.

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Please note:

Due­to­their­design­ball­valves­are­not­fit­to­function­as­a­throttle.­Therefore­ball­valves­have­to­be­turned­as­far­as­they­

will go in order to avoid destruction of the sealing cups.

To ascertain proper operation recommendations of the manufacturer regarding pressure and temperature have to be adhered to.

5.3.1.3 Special designs with logic valves

HYDAC-SYSTEM offer also other safety and shut-off blocks up to a nominal value of DN 160. They are custom-made for special accumulator stations.

Fig. DSV

Type:­ DSV-10-M-2.1/X/....

Nominal value: 10 liter

Max. operating excess pressure: up to 350 bar Pressure relief valve: nominal value DN10

Type: special edition Nominal value: up to DN 160

Fig. Special design with logic valve

337 5.3.2 Safeguarding the gas side

Inadmissible transgressions of pressure on the gas side especially due to increased ambient temperature, like in the case of­a­fire,­have­to­be­secured­by­means­of­a­complete­unloading­or­controlled­depressurization.

HYDAC offers three different and standardized means of protection:

•­fire­protection­(prevents­the­machine­from­melting)­

•­burst­plates

•­gas­safety­valves

5.3.2.1 Fire protection

Protection by means of complete unloading if pressure and limiting temperature are breached.

Protection units against melting is possible up to an admissible operational pressure of 690 bar and a temperature range of­-10°­to­+80°C.­Their­melting­point­is­at­approximately­160°C­to­170°C­and­unloads­the­gas­pressure­by­releasing­the­

nitrogen­completely,­if­the­limiting­temperature­is­breached,­like­in­the­case­of­a­fire.­

Fig. GSV

Fig. Component with safety function

Fig. Melting point safety device Melting point safety device:

Simple­retrofitting by replacing the sealing cap with the melting point safety device.

338

5.3.2.2 Burst plates

Protection by means of complete unloading if pressure limits are breached.

Burst plates are designed for different response pressures and are delivered with a declaration of conformity. If the pressure limit is breached the burst plate is destroyed thus unloading the gas pressure by releasing the nitrogen completely.

Stainless­steel­or­steel­/­nickel­alloys­are­materials­used­for­burst­plates.

5.3.2.3 Gas safety valves

Protection by means of controlled pressure reduction if pressure limits are breached.

Gas safety valve GSV6 is a directly acting, spring-loaded safety valve with a setting range of 30 to 370 bar and a

­temperature­range­of­-20°C­to­+80°C.­All­parts­of­the­valve­are­made­of­stainless­steel­and­therefore,­it­can­be­used­for­

a multitude of applications. GSV6 is also delivered with a declaration of conformity. Due to the self-centering washer a mounting of this valve is very easy and safe.

Fig.­Rupture­disks­/­bursting­disks hexagonal SW 19

thread:­1/4''­NPT

rupture disk

thread:­G­1/2''

Fig. Gas safety valve

339 5.3.2.4 Gas safety block

Design:

Gas safety block GSB450 consists of a block made of brass (other materials upon request) with integrated breather and shut-off valve plus ports for:

•­gas­safety­valve­(GSV6)

•­gas­charging­valve­(i.­e.­minimess)

•­manometer

•­pressure­transducer­or­pressure­switch

•­burst­plate

•­fire­protection­unit­(against­melting)

The connector (port) for the gas safety valve is designed as a check valve. Therefore the valve can be changed, even if the system is pressurized.

Function:

GSB450­is­an­adapter­block,­which­is­mounted­to­a­hydraulic­accumulator­on­the­gas­side­and­which­can­be­fitted­with­

various pressure components, charging inlets, safety valves and other safety components.

Advantages:

•­compact­design

•­flexible­fitting­possibilities

•­variable­indicators­are­possible­(bar.­mpa,­analogous)

•­pressure­indicators­according­to­customer­needs

•­charging­of­accumulator­with­nitrogen­without­FPU-1,­directly­via­Minimess-valve

•­checking­of­pre-charge­pressure­without­FPU-1 Technical data:

Medium: Nitrogen (N₂)

Admissible operational temperature:­ -20­to­+80°C­(other­options­upon­request) Max. operational excess pressure: 400 bar

Dimensions (basic design): max. hight: max. approx. 120 mm width: max. approx. 86 mm depth: max. approx. 125 mm

Fig. Gas safety block

341

6 Application of hydraulic accumulators

In document Influencia de la diversidad inicial y la pauta de cambio ambiental en a evolución del bacteriófago Qβ (página 45-149)