Parker Hannifin Accumulators and Receivers User Manual
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Accumulators and Receivers
Catalog C-1, May 2016
Page 2 / Catalog C-1, Accumulators and Receivers
Table of Contents
Accumulators and Receivers
Typical Piping Diagram ......................................................3
Steel Suction Line Accumulators ..............................................4
Copper Vertical, Horizontal, and Stand-Pipe Accumulators - OEM only ............11
Steel Receivers............................................................13
Terms of Sale with Warranty Limitations ......................................16
⚠WARNING – USER RESPONSIBILITY
Failure or improper selection or improper use of the products described herein or related items can cause death, personal injury and property damage.
This document and other information from Parker Hannin Corporation, its subsidiaries and authorized distributors provide product or system options for further investigation
by users having technical expertise.
The user, through its own analysis and testing, is solely responsible for making the nal selection of the system and components and assuring that all performance, endurance,
maintenance, safety and warning requirements of the application are met. The user must analyze all aspects of the application, follow applicable industry standards, and follow
the information concerning the product in the current product catalog and in any other materials provided from Parker or its subsidiaries or authorized distributors.
To the extent that Parker or its subsidiaries or authorized distributors provide component or system options based upon data or specications provided by the user, the user
is responsible for determining that such data and specications are suitable and sufcient for all applications and reasonably foreseeable uses of the components or systems.
OFFER OF SALE
The items described in this document are hereby offered for sale by Parker Hannin Corporation, its subsidiaries or its authorized distributors. This offer and its acceptance are
governed by the provisions stated in the detailed “Offer of Sale” elsewhere in this document or available at www.parker.com.
Typical Piping Diagram
Suction Line
Filter-Drier
Accumulator
*
Liquid Line
Solenoid
Valve
*
Liquid
*
Liquid Line
Filter-Drier
*
Receiver
Moisture &Liquid
Indicator
Liquid
Catalog C-1, Accumulators and Receivers / Page 3
Thermostatic
Expansion Valve
ASC Auxiliary
Side Connector
Refrigerant
Distributor
*
TEVs,
Assemblies
Saturated Liquid &
Vapor at TEV Outlet
Distributors, Tube
This schematic is for component location
only, not a typical piping recommendation.
LAC
Head
Pressure
Control
ETK/RTK
Acid Test Kit
Valve
*
Condensed
Liquid
Discharge Gas Bypassed
External Equalizer Connection
EVAPORATOR
*
HGBE
Discharge
Bypass
CONDENSER
Condenser Bypass Discharge Gas
*
EBV
Ball Valve
Valve
Hot Gas
Solenoid
*
ORIT
Evaporator Pressure
Regulating Valve
External Equalizer
Connection
Valve
*
COMPRESSOR
CROT
Crankcase
Pressure
Regulating
*
Valve
Suction Line
Models Available
*
Superheated Suction Gas
Page 4 / Catalog C-1, Accumulators and Receivers
Steel Suction Line Accumulators
Design
The function of a suction line accumulator in a heat pump or refrigeration system
is to catch and hold any unused portion of
the system charge. The device must also
prevent liquid slugging of the compressor and excessive refrigerant dilution of
the compressor oil.
The accumulator must return refrigerant
and oil to the compressor at a sufficient
rate to maintain both system operating
efficiency and proper crankcase oil level.
To make sure these tasks are accomplished, system designers must consider
the following items:
■ A properly sized and protected oil re-
turn orifice is required to ensure positive oil (and refrigerant) return to the
compressor
■ The accumulator must have sufficient in-
ternal volume
■ The pressure drop across the accumula-
tor should be as low as possible
Oil return at a minimum flow rate is
controlled by the outlet U-tube size.
Refrigerant and oil will be returned to
the compressor by pressure drop across
the orifice metering area and the liquid
head above the orifice. Other design
requirements include safe working pressure, agency approvals and corrosion
resistance.
Figure 1 illustrates a typical accumulator with an inlet defector. The shape of
the deflector directs the inlet flow in a
slightly downward tangential direction.
The inlet to the U-tube is located behind
the inlet deflector to prevent liquid carryover and is bell-shaped to reduce the
sudden contraction loss of the highvelocity gas. The U-tube diameter is
selected to minimize pressure drop at
high flow rates yet provide adequate oil
return at low flow rates.
Other features include a 50 x 60 mesh
screen to protect the oil return orifice,
an anti-siphon hole and a fusible alloy
plug in the accumulator. The anti-siphon
hole located near the outlet of the U-tube
prevents liquid from siphoning into the
outlet tube and compressor during an offcycle. The fusible alloy plug is generally
a U.L. requirement since it is a safety
device to protect against excessive pressure in the event of a fire.
Figure 1
Typical accumulator with inlet deflector baffle.
Selection
Accumulator selection can be fine-tuned
for best performance. This involves the
sizing of the accumulator and the sizing
of the orifice. The controlling factor for
both types is the type of metering device
used in the system. In systems using a
fixed orifice, the accumulator holding
capacity should be about 70% of the
system charge. This provides adequate
holding capacity during operation with
blocked or fouled heat exchanger coils.
The resulting high discharge/low suction
pressure condition will result in more
liquid refrigerant in the accumulator. The
oil return orifice size should be small to
prevent excess liquid refrigerant being
returned to the compressor. For these
systems, a 0.040 inch (1.02 mm) diameter orifice is the recommended starting
point.
For systems with a thermostatic expan-
sion valve (TEV), the accumulator holding capacity should be approximately
50% of the system charge. At startup
and after defrost the bulb of the TEV is
warm. Until the valve regains control,
the accumulator plays a role in preventing liquid slugging of the compressor.
The accumulator must also contend with
off cycle refrigerant migration. At shut-
down, the accumulator is the coldest
component in the system. This results
in migration of liquid refrigerant to the
device. This type of system needs to
return the refrigerant to circulation more
quickly than the fixed orifice system.
For these systems, a 0.055 inch (1.4 mm)
diameter orifice allows quick return of
the liquid refrigerant. The recommended
sizes of the orifices can be further tested
for optimum results. Other size orifices
are possible to satisfy the characteristics
required by the system designer.
New Refrigerants
The introduction of alternative refrigerants and oils requires reviewing the
design of components within the system, including suction accumulators. As
previously stated, the accumulator is the
coldest component in the system. The
new refrigerants and oils may or may
not be fully miscible in the temperature
range the accumulator normally operates. The oil and refrigerant can separate
into oil rich and refrigerant rich layers
in the accumulator, with the refrigerant
rich layer at the bottom. The oil return
orifice would be located in the refrigerant rich layer.
The solution to this problem is to provide
active mixing of the layers in the accumulator. This is accomplished by the
shape and position of the inlet deflector
and outlet U-tube. The inlet flow stream
is directed tangentially into the liquid
layers in the bottom of the accumulator.
The resulting circulation of the liquid
past the off center U-tube forces a mixing of the oil and refrigerant layers.
Field Replacement
The accumulator should be changed
when a compressor is replaced. The
old accumulator may contain contaminants from the problem that caused the
compressor failure. There may also be
considerable oil remaining from the first
compressor if a gradual loss of refrigerant caused the failure. This amount
coupled with the oil in the replacement
compressor may create an oil overcharge
condition.
Catalog C-1, Accumulators and Receivers / Page 5
Steel Suction Line Accumulators
U-Tube Style Accumulators – VA, PA and VPA Series
The U-tube accumulator design is a result of extensive laboratory testing of
various designs. It takes into account essential requirements such as safe holding
volume (relative to the system’s total charge), protected flow control for positive
refrigerant and oil return, and minimum pressure drop across the accumulator.
Parker offers standard accumulator models designed for application on heat pump and
refrigeration systems from 1/4 ton (.88 kW) through 28.5 tons (100.2 kW). Liquid
refrigerant holding requirements of suction accumulator may vary by application.
Features and Benefits
■ Solid copper connections (except where noted in the following tables)
■ U-tube design for maximum flow of refrigerant and minimum oil entrapment
■ Inlet flow deflector guides refrigerant toward wall for smooth tangential flow and gradual
expansion
■ Baffled U-tube entrance is positioned behind the inlet flow deflector to prevent unwanted
liquid refrigerant from entering and damaging compressor at all rated conditions
■ Metering orifice matched to system capacity which optimizes liquid refrigerant and oil
flow return back to compressor at all rated conditions
■ Protective screen and orifice assembly on U-tube protects against contaminants affecting
metering function
■ Minimum pressure drop and Maximum refrigerant flow
■ VA and VPA models are U.L. Listed for USA and Canada for 300 psig (20.7 bar) maximum
working pressure under SA5764-SKXY/SKXY7
■ PA models are U.L. Listed for USA and Canada for 355 psig (24.5 bar) maximum working
pressure under SA5764-SKXY/SKXY7
■ Powder coating surpasses 500 hour ASTM salt spray
■ Integral 430°F (221°C) fuse plugs on larger models
■ Compatible with CFC, HCFC and HFC refrigerants including R-22, R-134a, R-404A, R-407C,
R-410A, R-500, R-502 and R-507
Dimensions and Flow Data
Refer to pages 6 through 10 for dimension values and flow data.
Page 6 / Catalog C-1, Accumulators and Receivers
Dimensions
IN
“VA” Series
“E”
OUT
“A”
“D”
“C”
“B”
“PA” and “VPA” Series
“E”
“D”
IN
OUT
“A”
“B”
“C”
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